| Abstracts: Suplementação |
|
|
Nº de abstracts = 45
Modificado em 23 Fevereiro de 2012 Effects of a combined essential amino acids/carbohydrate supplementation on muscle mass, architecture and maximal strength following heavy-load training.Vieillevoye S, Poortmans JR, Duchateau J, Carpentier A.: European journal of applied Physiology, 2010, 110(3):479-88. Laboratory for Biometry and Exercise Nutrition, Université Libre de Bruxelles, 808 route de Lennik, CP 640, 1070 Brussels, Belgium. Increase in myofibrillar protein accretion can occur in the very early post-exercise period and can be potentiated by ingestion of essential amino acid (EAA). Furthermore, strength exercise induces important disturbances in protein turnover, especially in novice athletes. The purpose of this investigation was to evaluate the effects of an EAA supplementation on muscle mass, architecture and strength in the early stages of a heavy-load training programme. 29 young males trained during 12 weeks. They were divided into a placebo (PLA) (n = 14) group and an EAA group (n = 15). At baseline, daily food intake and nitrogenous balance were assessed with a food questionnaire over 7 days and two 24-h urine collections. The effect of training on muscle mass was assessed by anthropometric techniques. Muscle thickness and pennation angle were recorded by ultrasonography of the gastrocnemius medialis (GM). Maximal strength during squat and bench press exercises were tested on an isokinetic ergometer. Training resulted in significant increase in muscle mass and strength in both PLA and EAA groups. Positive linear regressions were found between nitrogen balance and increase in muscle mass in the PLA group (P < 0.01, r2 = 0.63) and between the initial strength and the increase in muscle strength in the EAA group (P <0.05, r2 = 0.29). EAA ingestion resulted in greater changes in GM muscle architecture. These data indicate that EAA supplementation has a positive effect on muscle hypertrophy and architecture and that such a nutritional intervention seems to be more effective in subject having lower nitrogen balance and/or lower initial strength.
Fish-oil supplementation enhances the effects of strength training in elderly women. Rodacki CL, Rodacki AL, Pereira G, Naliwaiko K, Coelho I, Pequito D, Fernandes LC
95(2):428-36, 2012 BACKGROUND: Muscle force and functional capacity generally decrease with aging in the older population, although this effect can be reversed, attenuated, or both through strength training. Fish oil (FO), which is rich in n-3 (omega-3) PUFAs, has been shown to play a role in the plasma membrane and cell function of muscles, which may enhance the benefits of training. The effect of strength training and FO supplementation on the neuromuscular system of the elderly has not been investigated. OBJECTIVE: The objective was to investigate the chronic effect of FO supplementation and strength training on the neuromuscular system (muscle strength and functional capacity) of older women. DESIGN: Forty-five women (aged 64 ± 1.4 y) were randomly assigned to 3 groups. One group performed strength training only (ST group) for 90 d, whereas the others performed the same strength-training program and received FO supplementation (2 g/d) for 90 d (ST90 group) or for 150 d (ST150 group; supplemented 60 d before training). Muscle strength and functional capacity were assessed before and after the training period. Results: No differences in the pretraining period were found between groups for any of the variables. The peak torque and rate of torque development for all muscles (knee flexor and extensor, plantar and dorsiflexor) increased from pre- to posttraining in all groups. However, the effect was greater in the ST90 and ST150 groups than in the ST group. The activation level and electromechanical delay of the muscles changed from pre- to posttraining only for the ST90 and ST150 groups. Chair-rising performance in the FO groups was higher than in the ST group. CONCLUSIONS: Strength training increased muscle strength in elderly women. The inclusion of FO supplementation caused greater improvements in muscle strength and functional capacity.
Effect of capsaicin supplementation on repeated sprinting performance. Opheim MN, Rankin JW
26(2):319-26, 2012 Opheim, MN, and Rankin, JW. Effect of capsaicin supplementation on repeated sprinting performance. J Strength Cond Res 26(2): 319-326, 2012-Performance in many team sports is partially dependent on the ability to perform repeatedly at high intensity. Previous research demonstrates that capsaicin (CAP) has physiological and metabolic effects that could influence exercise performance and inflammation. The purpose of this study was to investigate the influence of CAP on performance of and the interleukin-6 (IL-6) response to repeated sprints. Nineteen healthy male experienced athletes, age 18-30 years, participated in a placebo (PCB)-controlled, crossover study. During 1 trial, they consumed 3 g·d cayenne (25.8 mg·d CAP) and the other a PCB for days. Directly after the supplementation period, they completed a repeated sprint test (RST) consisting of 15 30-m maximal effort sprints on 35-second intervals with sprint times measured via an electronic dual-beam timing system. Fasted blood draws for IL-6 were taken at baseline before supplementation, 45 minute pre-RST, and immediately post-RST. Rate of perceived exertion (RPE), muscle soreness (MS), and gastrointestinal distress (GD) for 5 symptom subscales were measured 1-minute pretest, during, posttest, and 1-minute posttest. The MS was additionally measured for 3-day posttest. Relative to the PCB, CAP significantly increased the sum of ratings of GD symptoms by 6.3-fold. There was no difference between treatments in fastest or mean sprint time, fatigue, IL-6 response, RPE, or MS. In summary, CAP did not influence repeated sprint performance or the IL-6 response but caused substantial GD. The CAP is not recommended for athletes involved in repeated sprinting.
Acute and chronic loading of sodium bicarbonate in highly trained swimmers. Joyce S, Minahan C, Anderson M, Osborne M 201202 112(2):461-9 In the present study, 200-m swim time in highly trained male swimmers was measured on two consecutive days (Trial 1 and Trial 2) and under three conditions [(1) acute loading, AcL; (2) chronic loading, ChL; (3) Placebo, PLA]. No sodium bicarbonate (NaHCO(3)) was administered between Trial 1 and Trial 2 under each condition. Blood lactate concentration ([La(-)]), base excess of extracellular fluid (BE(ecf)), plasma bicarbonate concentration ([HCO(3) (-)]) and pH were determined before and after capsule administration as well as at 0, 3, 5, 15 and 30 min after each 200-m swim trial. Swim time was not different among AcL, ChL or PLA for Trial 1 or 2 and we observed no change in 200-m swim time from Trial 1 to 2 under any condition (F = 0.48, P = 0.80). [HCO(3) (-)], pH and BE(ecf) measured after capsule administration was higher during AcL and ChL when compared with PLA (P 0.05). The results indicate that acute and chronic loading of NaHCO(3) does not improve 200-m swim time in highly trained male swimmers.
The effects of chronic betaine supplementation on exercise performance, skeletal muscle oxygen saturation and associated biochemical parameters in resistance trained men. Trepanowski JF, Farney TM, McCarthy CG, Schilling BK, Craig SA, Bloomer RJ Journal of strength and conditioning research / National Strength & Conditioning Association 25(12):3461-71, 2011 Dez 1Cardiorespiratory/Metabolic Laboratory, The University of Memphis, Memphis, Tennessee; and 2Danisco, Tarrytown, New York. Trepanowski, JF, Farney, TM, McCarthy, CG, Schilling, BK, Craig, SA, and Bloomer, RJ. The effects of chronic betaine supplementation on exercise performance, skeletal muscle oxygen saturation, and associated biochemical parameters in resistance trained men. J Strength Cond Res 25(12): 3461-3471, 2011-We examined the effects of chronic betaine supplementation on exercise performance and associated parameters in resistance trained men. Men were randomly assigned in a double-blind manner using a crossover design to consume betaine (2.5 g of betaine mixed in 500 ml of Gatorade®) or a placebo (500 ml of Gatorade®) for 14 days, with a 21-day washout period. Before and after each treatment period, tests of lower- and upper-body muscular power and isometric force were conducted, including a test of upper-body muscular endurance (10 sets of bench press exercise to failure). Muscle tissue oxygen saturation (StO2) during the bench press protocol was measured via near infrared spectroscopy. Blood samples were collected before and after the exercise test protocol for analysis of lactate, nitrate/nitrite (NOx), and malondialdehyde (MDA). When analyzed using a repeated measures analysis of variance, no significant differences were noted between conditions for exercise performance variables (p > 0.05). However, an increase in total repetitions (p = 0.01) and total volume load (p = 0.02) in the 10-set bench press protocol was noted with betaine supplementation (paired t-tests), with values increasing approximately 6.5% from preintervention to postintervention. Although not of statistical significance (p = 0.14), postexercise blood lactate increased to a lesser extent with betaine supplementation (210%) compared with placebo administration (270%). NOx was lower postintervention as compared with preintervention (p = 0.06), and MDA was relatively unchanged. The decrease in StO2 during the bench press protocol was greater with betaine vs. placebo (p = 0.01), possibly suggesting enhanced muscle oxygen consumption. These findings indicate that betaine supplementation results in a moderate increase in total repetitions and volume load in the bench press exercise, without favorably impacting other performance measures.
The effects of Lyprinol(®) on delayed onset muscle soreness and muscle damage in well trained athletes: A double-blind randomised controlled trial. Pumpa KL, Fallon KE, Bensoussan A, Papalia S Complementary therapies in medicine 19(6):311-8, 2011 Dez National Institute of Sport Studies, University of Canberra, Canberra, Australia. OBJECTIVES: The aim of the study was to determine if Lyprinol(®) is effective in reducing pain, indicators of inflammation and muscle damage, and in turn improving performance in well trained athletes suffering from delayed onset muscle soreness (DOMS). DESIGN: A double blind randomised placebo controlled trial. SETTING: Twenty well trained male volunteers, matched by VO(2max) were randomly assigned to consume 200mg of Lyprinol(®) or an indistinguishable placebo daily for 8 weeks prior to a downhill treadmill running episode designed to induce DOMS. MAIN OUTCOME MEASURES: Performance measures (Kin-Com, counter movement and squat jump), pain assessments (visual analogue scale, algometer) and blood analyses (Interleukin-1, Interleukin-6, Interleukin-10, tumour necrosis factor-a, C-reactive protein, myoglobin, creatine kinase) were assessed at 7 time points over 5 days (pre, post, 4, 24, 48, 72 and 96h after the downhill run). RESULTS: No statistically significant differences were identified in any parameters between the active and placebo groups at any time point. CONCLUSION: After 2 months ingestion of Lyprinol(®) at the currently recommended dosage (200mg/day) and a demanding eccentric exercise intervention, Lyprinol(®) did not convincingly affect DOMS and indicators of muscle damage.
Statin-associated changes in skeletal muscle function and stress response after novel or accustomed exercise. Meador BM, Huey KA Muscle & nerve 44(6):882-9, 2011 Dez Department of Kinesiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA. Introduction: The most common side effect of statins, myopathy, is more likely in exercisers. We investigated the interaction of statin treatment with novel vs. accustomed exercise on muscle function, heat shock protein (Hsp) expression, and caspase activation. Methods: Mice received daily cerivastatin or saline for 2 weeks, with/without wheel running (RW) (novel/sedentary). Accustomed groups completed 2 weeks of RW before statins. At 4 weeks, plantarflexor isometric force, Hsp25, aB-crystallin, caspase-3 and -9, and plasma creatine kinase (CK) were quantified. Results: Statins reduced force in sedentary and novel groups, compared with saline, by 15% and 27%, respectively. Muscle fatigability increased 21% and 30% with statins compared with saline in sedentary and novel groups, respectively. Accustomed exercise prevented statin-associated force loss and increased fatigability. CK did not correlate with functional outcomes. RW increased Hsp protein in all groups. Conclusion: Our results suggest that exercise prior to statin treatment can protect against decrements in muscle function. Muscle Nerve 2011.
Soy protein based supplementation supports metabolic effects of resistance training in previously untrained middle aged males. Deibert P, Solleder F, K Nig D, Vitolins MZ, Dickhuth HH, Gollhofer A, Berg A The aging male : the official journal of the International Society for the Study of the Aging Male 14(4):273-9, 2011 Dez Department of Rehabilitative and Preventive Sports Medicine, University Hospital, Freiburg, Germany. Abstract Objective.?To determine changes in body composition, physical performance, metabolic and hormonal parameters induced by lifestyle counselling, resistance training and resistance training with soy protein based supplemention in middle aged males. Design.?Randomised controlled study consisting of resistance training without (RT-G) or with (RTS-G) a soy protein based supplement and a control group with lifestyle education only (LE-G). Subjects.?Forty healthy middle aged men (50?65 years, BMI 25?29.9 kg/m(2)). Measurements.?Changes in body weight (BW) and waist circumference (WC) were measured and body composition (BC), fat mass (FM), lean body mass (LBM) were measured by skin fold anthropometry at baseline and after 12 weeks of intervention. In addition, changes in physical fitness, metabolic and hormonal parameters (lipids, glucose, fructosamines, insulin, insulin-like growth factor-1, Leptin, human growth hormone, dehydroepiandrosterone, testosterone, hs-CRP, Il-6) were evaluated. Results.?Thirty-five participants completed the 12 week study. No significant changes in BW were noted although RM and WC dropped and LBM increased after training, particularly in the RTS group (FM 22.6???5.5?kg to 21.2???4.7?kg; LBM 68.5???7.2?kg to 70.1???7.4; p?
Quercetin and Endurance Exercise Capacity: A Systematic Review and Meta-analysis. Kressler J, Millard-Stafford M, Warren GL Medicine and science in sports and exercise 43(12):2396-404, 2011 Dez 1School of Applied Physiology, Georgia Institute of Technology, Atlanta, GA; and 2Division of Physical Therapy, Georgia State University, Atlanta, GA. UNLABELLED: Quercetin is a dietary flavonoid purported to improve human endurance exercise capacity. However, published findings are mixed. PURPOSE: The study's purpose was to perform a systematic review of the literature and meta-analysis to examine whether quercetin ingestion increases endurance exercise capacity. METHODS: A search of the literature was conducted using the key words quercetin, performance, exercise, endurance, and aerobic capacity. Eleven studies were identified as meeting the inclusion criteria providing data on 254 human subjects. Across all studies, subject presupplementation V?O2max ranged from 41 to 64 mL·kg·min (median = 46), and median treatment duration was 11 d with a median dosage of 1000 mg·d. Effect sizes (ES) were calculated as the standardized mean difference, and meta-analyses were completed using a random-effects model. RESULTS: The ES calculated for all studies combining V?O2max and endurance performance measures indicates a significant effect favoring quercetin over placebo (ES = 0.15, P = 0.021, 95% confidence interval = 0.02-0.27), but the magnitude of effect is considered between trivial and small, equating to a ~3% improvement of quercetin over placebo. Using a subgroup meta-analysis comparing quercetin's effect on endurance exercise performance versus V?O2max, no significant difference was found (P = 0.69). Meta-regression of study ES relative to subjects' fitness level or plasma quercetin concentration achieved by supplementation was also not significant. CONCLUSIONS: On average, quercetin provides a statistically significant benefit in human endurance exercise capacity (V?O2max and endurance exercise performance), but the effect is between trivial and small. Experimental factors that explain the between-study variation remain to be elucidated.
Oral tyrosine supplementation improves exercise capacity in the heat. Tumilty L, Davison G, Beckmann M, Thatcher R European journal of applied physiology 111(12):2941-50, 2011 Dez Department of Sport and Exercise Science, Aberystwyth University, Carwyn James Building, Penglais Campus, Aberystwyth, Ceridigion, SY23 3FD, Wales, UK, Este endereço de e-mail está protegido de spam bots, pelo que necessita do Javascript activado para o visualizar . Increased brain dopamine availability improves prolonged exercise tolerance in the heat. It is unclear whether supplementing the amino-acid precursor of dopamine increases exercise capacity in the heat. Eight healthy male volunteers [mean age 32 ± 11 (SD) years; body mass 75.3 ± 8.1 kg; peak oxygen uptake ([Formula: see text]) 3.5 ± 0.3 L min(-1)] performed two exercise trials separated by at least 7 days in a randomised, crossover design. Subjects consumed 500 mL of a flavoured sugar-free drink (PLA), or the same drink with 150 mg kg body mass(-1) tyrosine (TYR) in a double-blind manner 1 h before cycling to exhaustion at a constant exercise intensity equivalent to 68 ± 5% [Formula: see text] in 30°C and 60% relative humidity. Pre-exercise plasma tyrosine:large neutral amino acids increased 2.9-fold in TYR (P 0.05). Subjects cycled longer in TYR compared to PLA (80.3 ± 19.7 min vs. 69.2 ± 14.0 min; P 0.05) despite longer exercise time in TYR. The results show that acute tyrosine supplementation is associated with increased endurance capacity in the heat in moderately trained subjects. The results also suggest for the first time that the availability of tyrosine, a nutritional dopamine precursor, can influence the ability to subjectively tolerate prolonged submaximal constant-load exercise in the heat.
Effects of acute supplementation with Rhodiola rosea and L-carnitine on exercise performance, cognitive function and cortisol in healthy active volunteers. Muñiz-Pumares D, Lage-Guede A, Firth-Clark A, Allgrove J British journal of sports medicine 45(15):A1, 2011, Dez Rhodiola rosea (RR) is an adaptogenic herb suggested to improve exercise and cognitive performance and reduce stress responses. Further, some evidence reports that L-carnitine (LC) can alter metabolism during exercise and improve performance. This study examined the effects of acute ingestion of a commercially available RR beverage (250 mg, 3% Rosavin) with and without LC (500 mg) on exercise performance, cognitive function and salivary cortisol. In a double-blind, randomised, crossover-design, 18 healthy, active men and women (age, 21±6 years; maximal oxygen uptake, VO(2)max 43±9 ml/min/kg) consumed 250 ml of a RR-LC, RR and placebo beverage 45 min before a cycle to fatigue at 77±11% of VO(2)max. Immediately before and after exercise, computerised cognitive tasks of Rapid Visual Information Processing (RVP), Visual Recognition Memory (VRM) and Stroop Colour-Word (Stroop) were completed. Expired gas and heart rate were recorded continuously during exercise. Capillary blood samples were taken for lactate analysis 2 min after cycling and saliva samples were collected before beverage ingestion, before and immediately after cognitive tests for cortisol analysis. Data were analysed using repeated measures ANOVAs with significance set at P<0.05. Time to fatigue, physiological and cognitive variables did not differ between treatments. Cortisol increased (P=0.028) after tests, but there was no effect of treatment on this response. However, exercise elicited higher RVP sustained attention (P<0.05), a faster response time in Stroop (P<0.05), but VRM was reduced. These findings suggest that acute RR-LC ingestion does not alter cognitive function, exercise performance or salivary cortisol. However, chronic supplementation or greater dosage might affect these results. These results show that exhaustive exercise reduces reaction time and increases attention, but memory outcomes become decreased.
Effects of carbohydrate and caffeine co-ingestion on a reliable simulated soccer-specific protocol. Ranchordas MK, Pattison P British journal of sports medicine 45(15):A5-6, 2011, DezThe aim of this study was to evaluate the effect of co-ingesting carbohydrate and caffeine (CHO+CAF) in comparison to carbohydrate (CHO) and placebo (PLA), during a reliable soccer-specific test (Currell et al, 2009). 8 university-standard soccer players ingested a PLA, a 6.4% CHO or 6.4% CHO and 160 mg CAF (CHO+CAF) solution on three occasions, in a double-blind randomised cross-over design, with each trial separated by 7 days. The protocol was 90 min in duration, made up of ten 6 min exercise blocks, each followed by soccer-specific skills tests (agility, dribbling, heading and kicking accuracy). Dependant variables (Agility, dribbling, heading, kicking accuracy, glucose, lactate, HR and RPE) were analysed using one-way repeated measures ANOVA. Significant difference (p 0.05) was reported for dribbling, heading and kicking accuracy. Blood glucose and lactate were elevated (p 0.05) compared to CHO. Blood glucose increased (p= 0.01) in the CHO trial compared to PLA, with no difference (p> 0.05) between CHO+CAF and CHO. No significant difference (p> 0.05) was reported for HR and RPE values across all trial conditions. Skill performance during simulated soccer activity improved with CHO+CAF supplementation in comparison to both CHO and PLA. CHO+CAF co-ingestion had no ergogenic benefit over CHO in the maintenance and availability of blood glucose however, CHO+CAF co-ingestion did allow players to sustain a higher work intensity as opposed to CHO and PLA beverages as shown by elevated blood lactate levels.
Effect of acute L-arginine supplementation on 20 km time trial performance in competitive male cyclists. Ranchordas MK, Whitehead T British journal of sports medicine 45(15):A11, 2011, dez Increasing literature has studied the effects of dietary nitrates and moreover, L-arginine supplementation on tolerance to exercise and O(2) consumption during exercise. However, few studies have investigated the effects of L-arginine on performance measures such as a time trial. It was hypothesised that an acute 3-day L-arginine supplementation would elicit a significant improvement in performance and reduce oxygen consumption during a 20 km time trial. 6 healthy male competitive cyclists (23 ± 5 y) participated in a double-blind crossover study, and consumed either one 500 m placebo (PLA) or L-arginine (ARG) beverage, containing 6 g of L-arginine, over a 2 week testing period. Following a 3-day supplementation, participants completed a ramped incremental test to exhaustion, followed by an hours rest and subsequently a 20 km time trial. Time trial completion time was reduced by 34 s (PLA 32:38 ± 1:50 vs ARG 32:04 ± 1:38 min, P<0.05), O(2) consumption during the time trial was also reduced (PLA 51.6 ± 8.2 vs ARG 47.5 ± 6.1 mL(.)kg(.)min(-1), P<0.05). Furthermore, both systolic and diastolic blood pressure were greatly reduced (PLA 132 ± 7 vs ARG 127 ± 7 mm Hg P<0.05 and PLA 79 ± 5 vs ARG 74 ± 5 mm Hg respectively, P0.05) although W(peak) was higher during the same test (PLA 385 ± 38 vs ARG 395 ± 39 W). In conclusion, acute 3-day L-arginine supplementation at a dose of 6 g(.)day(-1) increases 20 km time trial performance and reduces O(2) consumption during time trial performance, in addition to reducing systolic and diastolic blood pressure. However, L-arginine appears to have no effect upon VO(2)max.
Creatine supplementation decreases oxidative DNA damage and lipid peroxidation induced by a single bout of resistance exercise. Rahimi R Journal of strength and conditioning research / National Strength & Conditioning Association 25(12):3448-55, 2011, dez Department of Physical Education and Sport Science, University of Kurdistan, Sanandaj, Iran; and Department of Exercise Physiology, Faculty of Physical Education and Sport Science, University of Guilan, Rasht, Iran. Rahimi, R. Creatine supplementation decreases oxidative DNA damage and lipid peroxidation induced by a single bout of resistance exercise. J Strength Cond Res 25(12): 3448-3455, 2011-Creatine (Cr), or methyl guanidine-acetic acid, can be either ingested from exogenous sources, such as fish or meat, or produced endogenously by the body, primarily in the liver. It is used as an ergogenic aid to improve muscle mass, strength, and endurance. Heretofore, Cr's positive therapeutic benefits in various oxidative stress-associated diseases have been reported in the literature and, recently, Cr has also been shown to exert direct antioxidant effects. Therefore, the purpose of this study was to investigate the effects of an acute bout of resistance exercise (RE) on oxidative stress response and oxidative DNA damage in male athletes and whether supplementation with Cr could negate any observed differences. Twenty-seven resistance-trained men were randomly divided into a Cr supplementation group (the Cr group [21.6 ± 3.6 years], taking 4 × 5 g Cr monohydrate per day) or a placebo (PL) supplementation group (the PL group [21.2 ± 3.2 years], taking 4 × 5 g maltodextrin per day). A double-blind research design was employed for a 7-day supplementation period. Before and after the seventh day of supplementation, the subjects performed an RE protocol (7 sets of 4 exercises using 60-90 1 repetition maximum) in the flat pyramid loading pattern. Blood and urine samples taken before, immediately, and 24-hour postexercise were analyzed for plasma malondialdehyde (MDA) and urinary 8-hydroxy-2-deoxyguanosine (8-OHdG) excretion. Before the supplementation period, a significant increase in the urinary 8-OHdG excretion and plasma MDA levels was observed after RE. The Cr supplementation induces a significant increase in athletics performance, and it attenuated the changes observed in the urinary 8-OHdG excretion and plasma MDA. These results indicate that Cr supplementation reduced oxidative DNA damage and lipid peroxidation induced by a single bout of RE.
Br J Sports Med
Issue: 15, A5-6Ranchordas MK et, al.
Effects of acute alkalosis and acidosis on performance: a meta-analysis. Carr AJ, Hopkins WG, Gore CJ.: Sports Medicine, 2011,10 - 41(10):801-14. Ingestion of agents that modify blood buffering action may affect high-intensity performance. Here we present a meta-analysis of the effects of acute ingestion of three such agents - sodium bicarbonate, sodium citrate and ammonium chloride - on performance and related physiological variables (blood bicarbonate, pH and lactate). A literature search yielded 59 useable studies with 188 observations of performance effects. To perform the mixed-model meta-analysis, all performance effects were converted into a percentage change in mean power and were weighted using standard errors derived from exact p-values, confidence limits (CLs) or estimated errors of measurement. The fixed effects in the meta-analytic model included the number of performance-test bouts (linear), test duration (log linear), blinding (yes/no), competitive status (athlete/nonathlete) and sex (male/female). Dose expressed as buffering mmoL/kg/body mass (BM) was included as a strictly proportional linear effect interacted with all effects except blinding. Probabilistic inferences were derived with reference to thresholds for small and moderate effects on performance of 0.5% and 1.5%, respectively. Publication bias was reduced by excluding study estimates with a standard error >2.7%. The remaining 38 studies and 137 estimates for sodium bicarbonate produced a possibly moderate performance enhancement of 1.7% (90% CL?±?2.0%) with a typical dose of 3.5?mmoL/kg/BM (~0.3?g/kg/BM) in a single 1-minute sprint, following blinded consumption by male athletes. In the 16 studies and 45 estimates for sodium citrate, a typical dose of 1.5?mmoL/kg/BM (~0.5?g/kg/BM) had an unclear effect on performance of 0.0% (±1.3%), while the five studies and six estimates for ammonium chloride produced a possibly moderate impairment of 1.6% (±1.9%) with a typical dose of 5.5?mmoL/kg/BM (~0.3?g/kg/BM). Study and subject characteristics had the following modifying small effects on the enhancement of performance with sodium bicarbonate: an increase of 0.5% (±0.6%) with a 1?mmoL/kg/BM increase in dose; an increase of 0.6% (±0.4%) with five extra sprint bouts; a reduction of 0.6% (±0.9%) for each 10-fold increase in test duration (e.g. 1-10 minutes); reductions of 1.1% (±1.1%) with nonathletes and 0.7% (±1.4%) with females. Unexplained variation in effects between research settings was typically ±1.2%. The only noteworthy effects involving physiological variables were a small correlation between performance and pre-exercise increase in blood bicarbonate with sodium bicarbonate ingestion, and a very large correlation between the increase in blood bicarbonate and time between sodium citrate ingestion and exercise. The approximate equal and opposite effects of sodium bicarbonate and ammonium chloride are consistent with direct performance effects of pH, but sodium citrate appears to have some additional metabolic inhibitory effect. Important future research includes studies of sodium citrate ingestion several hours before exercise and quantification of gastrointestinal symptoms with sodium bicarbonate and citrate. Although individual responses may vary, we recommend ingestion of 0.3-0.5?g/kg/BM sodium bicarbonate to improve mean power by 1.7% (±2.0%) in high-intensity races of short duration.
Effects of six weeks of quercetin supplementation on physical performance in ROTC cadetsBigelman KA, Fan EH, Chapman DP, Freese EC, Trilk JL, Cureton KJ.: Military medicine, 2010, 175(10):791-8. Metabolism and Body Composition Laboratory, Department of Kinesiology, Ramsey Center, Rm. 109, 300 River Street, University of Georgia, Athens, GA 30602, USA. OBJECTIVE: To investigate the effects of 6 weeks of quercetin supplementation on physical performance during military physical training. METHODS: Using a randomized, double-blind, repeated-measures, placebo-controlled design, 58 healthy, moderately trained men and women were randomly assigned to quercetin (Q) or placebo (P) groups. Peak oxygen uptake (VO(2peak)) during maximal effort uphill treadmill running and four physical performance measures (Army Physical Fitness Test, [APFT], Baumgartner Modified Pull-Up Test [BMPU], Wingate Anaerobic Test [WanT], and a 36.6-m sprint) were evaluated before and after 42-54 days of supplementation with 1 g/d of quercetin with vitamins and other substances in a soft chew or placebo chew. RESULTS: Pretreatment-to-posttreatment changes in VO(2peak) and physical performance were not significantly different (p > 0.05) in Q and P. CONCLUSIONS: Six weeks of dietary quercetin supplementation in moderately trained individuals conducting military physical training did not improve VO(2peak) or performance on the APFT, BMPU, WAnT, and 36.6-m sprint.
Plasma antioxidant responses and oxidative stress following a soccer game in elite female players.Andersson H, Karlsen A, Blomhoff R, Raastad T, Kadi F.: Scandinavian Journal of Medicine & Science in Sports, 2010, 20(4):600-8. School of Health and Medical Sciences, Orebro University, Orebro, Sweden. We aimed to investigate markers of oxidative stress and levels of endogenous and dietary antioxidants in 16 elite female soccer players in response to a 90-min game (average intensity 82+/-3% HRpeak). Blood samples were taken before, immediately and 21 h after the game. Plasma-oxidized glutathione, the ratio of reduced to oxidized glutathione (GSH:GSSG) and lipid peroxidation measured by d-ROMs were used as markers of oxidative stress. Plasma endogenous [uric acid, total glutathione (TGSH)] and dietary antioxidants (alpha-tocopherol, ascorbic acid, total carotenoids and polyphenols) were analyzed using liquid chromatography and the Folin-Ciocalteu method. Exercise induced an acute increase (P<0.05) in GSSG, uric acid, TGSH, alpha-tocopherol, and ascorbic acid. In parallel, the GSH:GSSG ratio and polyphenols decreased (P<0.05). GSSG, GSH:GSSG ratio, uric acid, TGSH, and ascorbic acid returned to baseline at 21 h, while polyphenols and alpha-tocopherol remained altered. Total carotenoids increased above baseline only at 21 h (P<0.05). Lipid peroxidation, measured by d-ROMs, remained unchanged throughout the study. Thus, intermittent exercise in well-trained female athletes induces a transient increase in GSSG and a decrease in the GSH:GSSG ratio, which is effectively balanced by the recruitment of both endogenous and dietary antioxidants, resulting in the absence of lipid peroxidation measured by d-ROMs.
Antioxidant responses to an acute ultra-endurance exercise: impact on DNA stability and indications for an increased need for nutritive antioxidants in the early recovery phaseNeubauer O, Reichhold S, Nics L, Hoelzl C, Valentini J, Stadlmayr B, Knasmüller S, Wagner KH.: The British journal of nutrition, 2010, 104(8):1129-38. Department of Nutritional Sciences, Emerging Field Oxidative Stress and DNA Stability, Faculty of Life Sciences, University of Vienna, Althanstraße 14, 1090 Vienna, Austria. Antioxidant requirements have neither been defined for endurance nor been defined for ultra-endurance athletes. To verify whether an acute bout of ultra-endurance exercise modifies the need for nutritive antioxidants, we aimed (1) to investigate the changes of endogenous and exogenous antioxidants in response to an Ironman triathlon; (2) to particularise the relevance of antioxidant responses to the indices of oxidatively damaged blood lipids, blood cell compounds and lymphocyte DNA and (3) to examine whether potential time-points of increased susceptibility to oxidative damage are associated with alterations in the antioxidant status. Blood that was collected from forty-two well-trained male athletes 2 d pre-race, immediately post-race, and 1, 5 and 19 d later was sampled. The key findings of the present study are as follows: (1) Immediately post-race, vitamin C, a-tocopherol, and levels of the Trolox equivalent antioxidant capacity, the ferric reducing ability of plasma and the oxygen radical absorbance capacity (ORAC) assays increased significantly. Exercise-induced changes in the plasma antioxidant capacity were associated with changes in uric acid, bilirubin and vitamin C. (2) Significant inverse correlations between ORAC levels and indices of oxidatively damaged DNA immediately and 1 d post-race suggest a protective role of the acute antioxidant responses in DNA stability. (3) Significant decreases in carotenoids and ?-tocopherol 1 d post-race indicate that the antioxidant intake during the first 24 h of recovery following an acute ultra-endurance exercise requires specific attention. Furthermore, the present study illustrates the importance of a diversified and well-balanced diet to maintain a physiological antioxidant status in ultra-endurance athletes in reference to recommendations.
Oral administration of the probiotic Lactobacillus fermentum VRI-003 and mucosal immunity in endurance athletes.Cox AJ, Pyne DB, Saunders PU, Fricker PA.: British journal of Sports Medicine, 2010, 44(4):222-6. Department of Physiology, Australian Institute of Sport, PO Box 176, Belconnen, ACT, 2616, Australia. OBJECTIVE: To evaluate the ability of a probiotic Lactobacillus fermentum VRI-003 (PCC) to enhance the mucosal immune system of elite athletes. DESIGN AND SETTING: A double-blind, placebo-controlled, crossover trial was conducted over a 4-month period of winter training. PARTICIPANTS; 20 healthy elite male distance runners. INTERVENTIONS: PCC was given at a daily dose of 1.26 x 10(10) as a freeze-dried powder in gelatin capsules. Placebo capsules contained an inert excipient. MAIN OUTCOME MEASURES: Treadmill performance (monthly), mucosal and systemic immunity (monthly), training (daily) and illness (daily) were assessed. Serum cytokine levels, salivary IgA levels and incidence, duration and severity of respiratory tract infections were measured. RESULTS: Subjects reported less than half the number of days of respiratory symptoms during PCC treatment (30 days) compared with placebo (72 days, p<0.001). Illness severity was also lower for episodes occurring during the PCC treatment (p = 0.06). There were no significant differences in the mean change in salivary IgA and IgA1 levels, or in interleukin (IL)4 and IL12 levels, between treatments. However, PCC treatment elicited a twofold (p = 0.07) greater change in whole-blood culture interferon gamma (IFNgamma) compared with placebo. No substantial changes in running performance measures were seen over the study period. CONCLUSIONS: Prophylactic administration of PCC was associated with a substantial reduction in the number of days and severity of respiratory illness in a cohort of highly trained distance runners. Maintenance of IFNgamma levels may be one mechanism underpinning the positive clinical outcomes.
The effect of sodium bicarbonate ingestion on high-intensity intermittent running and subsequent performancePrice MJ, Simons C.: Journal of strength and conditioning research / National Strength & Conditioning Association, 2010, 24(7):1834-42. Department of Physiology and Sports Science, Faculty of Health and Life Sciences, Coventry University, Coventry, United Kingdom. The purpose of this study was to determine the effects of sodium bicarbonate (NaHCO3) ingestion on intermittent running and subsequent performance. Eight healthy men volunteered to take part in the study. One hour after the ingestion of either NaHCO(3) or placebo (sodium chloride; NaCl) participants undertook 20 x 24-second runs on a motorized treadmill at the velocity eliciting maximal oxygen uptake (100% v-VO(2)max). After sprint 20 participants performed a run to volitional exhaustion at 120% v-VO(2)max. Capillary blood samples for blood pH, bicarbonate ([HCO(3)]), and lactate ([Bla]) concentration were taken pre and postingestion, every fifth sprint and after the performance run. After ingestion of NaHCO(3), blood [HCO(3)] increased from resting values (p < 0.05), and the increase in pH approached significance. Blood [HCO(3)(-)] continually decreased throughout intermittent exercise (p < 0.05) and decreased further after performance in both trials (p < 0.05). [Bla] was similar in both trials throughout intermittent exercise but was greater at exhaustion for NaHCO(3) (main effect for trial; p < 0.05). There was no significant difference in performance of the group between trials (78 +/- 22 and 75 +/- 22 seconds for NaHCO(3) and NaCl, respectively). The intercept of the relationships between [Bla] and [HCO(3)(-)] and between [Bla] and pH was greater during NaHCO(3) (p 0.05). The results of this study suggest that the ingestion of NaHCO(3) before intermittent type exercise was sufficient to induce metabolic alkalosis but did not significantly affect performance. However, because significant individual variations in performance were observed, an individual approach to bicarbonate ingestion is recommended based on the intensity and duration of the required performance.
Hemopoietic and angiogenetic progenitors in healthy athletes: different responses to endurance and maximal exercise.Bonsignore MR, Morici G, Riccioni R, Huertas A, Petrucci E, Veca M, Mariani G, Bonanno A, Chimenti L, Gioia M, Palange P, Testa U.: Journal of Applied Physiology (Bethesda, Md. : 1985), 2010-07 109(1):60-7. Biomedical Department, Internal and Specialistic Medicine (DIBIMIS), Section of Pneumology, University of Palermo, Via Trabucco, 180, 90146 Palermo, Italy. The effects of endurance or maximal exercise on mobilization of bone marrow-derived hemopoietic and angiogenetic progenitors in healthy subjects are poorly defined. In 10 healthy amateur runners, we collected venous blood before, at the end of, and the day after a marathon race (n = 9), and before and at the end of a 1.5-km field test (n = 8), and measured hemopoietic and angiogenetic progenitors by flow cytometry and culture assays, as well as plasma or serum concentrations of several cytokines/growth factors. After the marathon, CD34(+) cells were unchanged, whereas clonogenetic assays showed decreased number of colonies for both erythropoietic (BFU-E) and granulocyte-monocyte (CFU-GM) series, returning to baseline the morning post-race. Conversely, CD34(+) cells, BFU-E, and CFU-GM increased after the field test. Angiogenetic progenitors, assessed as CD34(+)KDR(+) and CD133(+)VE-cadherin(+) cells or as adherent cells in culture expressing endothelial markers, increased after both endurance and maximal exercise but showed a different pattern between protocols. Interleukin-6 increased more after the marathon than after the field test, whereas hepatocyte growth factor and stem cell factor increased similarly in both protocols. Plasma levels of angiopoietin (Ang) 1 and 2 increased after both types of exercise, whereas the Ang-1-to-Ang-2 ratio or vascular endothelial growth factor-A were little affected. These data suggest that circulating hemopoietic progenitors may be utilized in peripheral tissues during prolonged endurance exercise. Endothelial progenitor mobilization after exercise in healthy trained subjects appears modulated by the type of exercise. Exercise-induced increase in growth factors suggests a physiological trophic effect of exercise on the bone marrow.
Anabolic androgenic steroids in amateur sports in the NetherlandsWoerdeman J, de Hon O, Levi M, de Ronde WP.: Nederlands tijdschrift voor geneeskunde, 2010 154(37):A2004. VU Medisch Centrum, Amsterdam, afd. Endocrinologie, the Netherlands. In the Netherlands an estimated 20,000 people use anabolic androgenic steroids (AAS). The use of AAS is particularly common in regular visitors to gyms and fitness centres. AAS are usually synthetic derivatives of testosterone with both an anabolic and an androgenic effect. AAS have many side effects like liver damage (oral use) or infections (intramuscular use), which can be explained partly by the androgenic effect and partly by the manner of use. Many of these side effects are only reported in case studies and have not been systematically investigated.
Physiological effects of caffeine, epigallocatechin-3-gallate, and exercise in overweight and obese women.Sarah E. Tobkin, Joel T. Cramer, and Jeffrey R. Stout: Abbie E. Smith, Christopher M. Lockwood, Jordan R. Moon, Kristina L. Kendall, David H. Fukuda, Appl. Physiol. Nutr. Metab., 2010, 35(5): 607–616. The aim of this study was to evaluate the combined effects of a 10-week exercise program with ingestion of caffeine and epigallocatechin-3-gallate (EGCG) on body composition, cardiovascular fitness, and strength in overweight and obese women. In a double-blind, placebo-controlled approach, overweight and obese women (n = 27) were randomly assigned to treatment groups with exercise (an active-supplementing group with exercise (EX-Act) and a placebo group with exercise (EX-PL)) or without exercise (an active-supplementing group without exercise (NEX-Act) and a placebo group without exercise (NEX-PL)). All participants consumed 1 drink per day for 10 weeks; EX-Act and EX-PL participated in a concurrent endurance and resistance training program. Changes in body composition were assessed using a 4-compartment model. Changes in muscle mass (MM) were evaluated using a DXA-derived appendicular lean–soft tissue equation. There was a significant time × treatment interaction for MM (p = 0.026) and total cholesterol (TC) (p = 0.047), and a significant time × training interaction for peak oxygen consumption (p = 0.046) and upper-body and lower-body strength (p < 0.05). Significant differences between the EX groups and NEX groups for percentage change in MM and peak oxygen consumption, and upper-body and lower-body strength, were revealed. Clinical markers for hepatic and renal function revealed no adverse effects. TC significantly decreased for the active-supplementing groups (EX-Act, NEX-Act). The current study suggests that implementing a caffeine–EGCG-containing drink prior to exercise may improve MM, fitness, and lipid profiles in overweight women.
Vitamin and mineral supplementation effect on muscular activity and cycling efficiency in master athletesJulien Louis, Christophe Hausswirth, François Bieuzen, and Jeanick Brisswalter: Appl. Physiol. Nutr. Metab. 35(3): 251–260 (2010).
Combination of sago and soy-protein supplementation during endurance cycling exercise and subsequent high-intensity endurance capacity.Ghosh AK, Rahaman AA, Singh R.: International Journal of Sport Nutrition and Exercise Metabolism, 2010, 20(3):216-23 Language: eng Country: United States Sports Centre, University of Malaya, Kuala Lumpur, Malaysia. The purpose of the study was to investigate whether a combination of sago and soy protein ingested during moderate-intensity cycling exercise can improve subsequent high-intensity endurance capacity compared with a carbohydrate in the form of sago and with a placebo. The participants were 8 male recreational cyclists with age, weight, and VO2max of 21.5 +/- 1.1 yr, 63.3 +/- 2.4 kg, and 39.9 +/- 1.1 ml . kg(-1) . min(-1), respectively. The design of the study was a randomized, double-blind placebo-controlled crossover comprising 60 min of exercise on a cycle ergometer at 60% VO2max followed by a time-to-exhaustion ride at 90% VO2max. The sago feeding provided 60 g of carbohydrate, and the sago-soy combination provided 52.5 g of carbohydrate and 15 g of protein, both at 20-min intervals during exercise. Times to exhaustion for the placebo, sago, and sago-soy supplementations were 4.09 +/- 1.28, 5.49 +/- 1.20, and 7.53 +/- 2.02 min, respectively. Sago-soy supplementation increased endurance by 84% (44-140%; p < .001) and by 37% (15-63%; p < .05) relative to placebo and sago, respectively. The plasma insulin response was elevated above that with placebo during sago and sago-soy supplementations. The authors conclude that a combination of sago and soy protein can delay fatigue during high-intensity cycling.
The influence of caffeine and carbohydrate coingestion on simulated soccer performance.Gant N, Ali A, Foskett A.: International Journal of Sport Nutrition and Exercise Metabolism, 2010, 20(3):191-7. Dept. of Sport and Exercise Science, University of Auckland, Auckland, New Zealand. Carbohydrate and caffeine are known to independently improve certain aspects of athletic performance. However, less is understood about physiological and performance outcomes when these compounds are coingested in a rehydration and carbohydrate-replacement strategy. The aim of this study was to examine the influence of adding a moderate dose of caffeine to a carbohydrate solution during prolonged soccer activity. Fifteen male soccer players performed two 90-min intermittent shuttle-running trials. They ingested a carbohydrate-electrolyte solution (CON) providing a total of 1.8 g/kg body mass (BM) of carbohydrate or a similar solution with added caffeine (CAF; 3.7 mg/kg BM). Solutions were ingested 1 hr before exercise and every 15 min during the protocol. Soccer passing skill and countermovement-jump height (CMJ) were quantified before exercise and regularly during exercise. Sprinting performance, heart rate, blood lactate concentration (La) and the subjective experiences of participants were measured routinely. Mean 15-m sprint time was faster during CAF (p = .04); over the final 15 min of exercise mean sprint times were CAF 2.48 +/- 0.15 s vs. CON 2.59 +/- 0.2 s. Explosive leg power (CMJ) was improved during CAF (52.9 +/- 5.8 vs. CON 51.7 +/- 5.7 cm, p = .03). Heart rate was elevated throughout CAF, and ratings of pleasure were significantly enhanced. There were no significant differences in passing skill, rating of perceived exertion, La, or body-mass losses between trials. The addition of caffeine to the carbohydrate-electrolyte solution improved sprinting performance, countermovement jumping, and the subjective experiences of players. Caffeine appeared to offset the fatigue-induced decline in self-selected components of performance.
Vitamin and mineral supplementation effect on muscular activity and cycling efficiency in master athletes.
Louis J, Hausswirth C, Bieuzen F, Brisswalter J.: Applied Physiology, Nutrition, and Metabolism = Physiologie appliquée, nutrition et metabolism, 2010, 35(3):251-60. University of Nice Sophia Antipolis, Nice, France. The influence of vitamin and mineral complex supplementation on muscular activity and cycling efficiency was examined in elderly endurance-trained master athletes during a heavy cycling trial. Master athletes were randomly assigned in a double-blind process to 1 of 2 treatment groups: antioxidant supplementation (n = 8: As group) or placebo (n = 8: Pl group) for 21 days. After that time, each subject had to perform a 10-min session of cycling on a cycloergometer at a heavy constant intensity. Twenty-four to 48 h after this session, subjects performed an isometric maximal voluntary contraction before and immediately after a fatiguing strength training (leg press exercise) and the same 10-min cycling test after fatigue. Isometric maximal voluntary force (MVF) of knee extensors was assessed before and after fatigue. Electromyographic (EMG) activity of the vastus medialis, the vastus lateralis (VL), and the biceps femoris was recorded with surface EMG. The knee-extensors MVF after the fatiguing exercise was reduced in similar proportions for both groups (As, -10.9%; Pl, -11.3%, p < 0.05). This MVF loss was associated with a significant reduction in EMG frequency parameters for both groups, with a lower decrease for the As group. Muscular activity and cycling efficiency during the cycling bouts were affected by the treatment. Cycling efficiency decreased significantly and the oxygen uptake slow component was higher after the fatiguing exercise for both groups. Furthermore, a decrease in cycling efficiency was associated with an increase in VL activity. However, these changes were significantly lower for the As group. The Results of the present study indicate an overall positive effect of vitamin and mineral complex supplementation on cycling efficiency after fatigue, in the endurance-trained elderly.
Vitamin D, muscle function, and exercise performance.Bartoszewska M, Kamboj M, Patel DR.: Pediatric Clinics of North America, 2010-06 57(3):849-61. Michigan State University College of Human Medicine, East Lansing, MI, USA. Vitamin D has an important role in skeletal muscles. Previously recognized for its effects on bone, it is now known that vitamin D has a much wider spectrum of usefulness for muscle. Studies indicate that vitamin D deficiency is pandemic. Those affected include the young and otherwise healthy members of the population, including athletes. Controversy exists regarding the amount of supplementation required to reverse deficiency and the relative effect of such a reversal on overall health. This article reviews current data on the role of vitamin D on muscle function, and explores the potential implications of its deficiency and supplementation on physical fitness and athletic performance.
No effects of three-week consumption of a green tea extract on time trial performance in endurance-trained men.Eichenberger P, Mettler S, Arnold M, Colombani PC.: International Journal for Vitamin and Nutrition Research. Internationale Zeitschrift für Vitamin- und Ernährungsforschung. Journal international de vi 201001 80(1):54-64. Department of Biology, ETH Zurich, Zurich, Switzerland. The purpose of this study was to examine the effects of three-week consumption of green tea extract (GTE) supplementation on time trial performance and metabolism during cycling in endurance athletes. Nine endurance-trained men participated in this double-blind and placebo-controlled cross-over study. At the end of the supplementation period with GTE (159 mg/day total catechins) or placebo, respectively, subjects cycled at 50 % of the individual maximal power output for 2 hours, followed by a 30-minute time trial. Respiratory gas exchange, fatty acids, 3-beta-hydroxybutyrate, lactate, glucose, interleukin-6, thiobarbituric acid reactive substances, creatine kinase, and C-reactive protein (CRP) were measured 1 hour before, during, and 1 hour after the exercise test. Blood lipids were measured at rest before cycling. There was no significant effect on performance, energy metabolism, or any other measured parameter, except for CRP, which was significantly reduced (p = 0.045) after GTE supplementation compared to placebo. GTE supplementation did not affect time trial performance and energy metabolism in endurance-trained men in the non-fasting state. Further studies with athletes, particularly in the fed state, but with higher GTE doses, are needed to address the question whether green tea may influence energy metabolism and performance in athletes.
Nutritional supplementation, performance, and oxidative stress in college soccer players.Arent SM, Pellegrino JK, Williams CA, Difabio DA, Greenwood JC.: Journal of Strength and Conditioning research / National Strength & Conditioning Association, 2010-04 24(4):1117-24. 1Department of Exercise Science and Sport Studies, Rutgers, the State University of New Jersey, New Brunswick, New Jersey, USA. The purpose of this study was to examine changes in performance and metabolic parameters in collegiate soccer players during preseason preparation and to determine the impact of a nutraceutical blend proposed to reduce oxidative stress. Male Division I college soccer players (n = 22) performed a progressive maximal treadmill test at the beginning and end of preseason to assess changes in Vo2max, velocity at lactate threshold (VLT), time-to-exhaustion, lipid hydroperoxide (LPO), 8-isoprostane, and creatine kinase (CK) response. After baseline testing, athletes were randomly assigned to receive the nutraceutical blend (EXP; n = 12) or an isocaloric equivalent (CON; n = 10) for 20 days of preseason training. DeltaVo2max (2.1 +/- 3.3 ml.kg.min, p = 0.007), DeltaVLT (0.8 +/- 1.4 km.h, p = 0.045), and Deltatime-to-exhaustion (39.4 +/- 77.4 seconds, p = 0.033) were improved across groups, but a significant effect of supplementation on performance was not seen. Changes in resting levels of CK from the beginning to end of preseason were significantly lower (p = 0.044) in EXP (64.8 +/- 188.4 U.L) than in CON (292.8 +/- 304.8 U.L). Additionally, EXP demonstrated a significant decrease in the magnitude of the 8-isoprostane response at Trial 2 compared with Trial 1 (effect size [ES] = -0.74), whereas CON had an increased response (ES = 0.20). A similar pattern was seen for LPO (p = 0.067). Preseason training in male college soccer players resulted in significant improvements in Vo2max, VLT, and time-to-exhaustion. Supplementing with a proprietary antioxidant and nutraceutical blend may enhance some of these effects as indicated by magnitude of the responses. However, it appears that the most notabl
Daily supplementation with iron plus folic acid, zinc, and their combination is not associated with younger age at first walking unassisted in malnourished preschool children from a deficient population in rural Nepal.Katz J, Khatry SK, Leclerq SC, Mullany LC, Yanik EL, Stoltzfus RJ, Siegel EH, Tielsch JM The Journal of Nutrition.: 2010-07 140(7):1317-21. Department of International Health and; 6Department of Epidemiology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA. A community-based, cluster-randomized, placebo-controlled trial of daily zinc and/or iron+folic acid supplementation was conducted in rural southern Nepal to examine motor milestone attainment among 3264 children 1-36 mo of age between 2001 and 2006. Treatment groups included placebo, zinc (10 mg), iron+folic acid (12.5 mg iron + 50 microg folic acid), and zinc+iron+folic acid (10 mg zinc + 12.5 mg iron + 50 microg folic acid). Infants received half of these doses. The iron arms were stopped November 2003 by recommendation of the Data Safety and Monitoring Board; zinc and placebo continued until January 2006. A total of 2457 children had not walked at the time of entry into the trial and 1775 were followed through 36 mo. Mean age at first walking unassisted did not differ among groups and was 444 +/- 81 d (mean +/- SD) in the placebo group, 444 +/- 81 d in the zinc group, 464 +/- 85 d in the iron+folic acid group, and 446 +/- 87 d in the iron+folic acid+zinc group. Results were similar after adjustment for age at enrollment, asset ownership, maternal literacy, and prior child deaths in the household and in children who consumed at least 60 tablets. Compared with placebo, iron+folic acid was associated with an adjusted mean delay of 28.0 d (95% CI: 11.3, 44.7) in time to walking among infants and the delay was more pronounced with mid-upper arm circumference (MUAC) < 9.5 cm [60.6 d, (95% CI: 28.5, 92.6)]. Risks and benefits of universal iron+folic acid supplementation of infants beyond improved hematologic status deserve further consideration. Amino acid supplements and recovery from high-intensity resistance training.Sharp CP, Pearson DR.: Journal of Strength and Conditioning research / National Strength & Conditioning Association, 2010-04 24(4):1125-30. Department of Health and Human Performance, College of Charleston, Charleston, South Carolina, USA. The purpose of this study was to investigate whether short-term amino acid supplementation could maintain a short-term net anabolic hormonal profile and decrease muscle cell damage during a period of high-intensity resistance training (overreaching), thereby enhancing recovery and decreasing the risk of injury and illness. Eight previously resistance trained males were randomly assigned to either a high branched chain amino acids (BCAA) or placebo group. Subjects consumed the supplement for 3 weeks before commencing a fourth week of supplementation with concomitant high-intensity total-body resistance training (overreaching) (3 x 6-8 repetitions maximum, 8 exercises). Blood was drawn prior to and after supplementation, then again after 2 and 4 days of training. Serum was analyzed for testosterone, cortisol, and creatine kinase. Serum testosterone levels were significantly higher (p < 0.001), and cortisol and creatine kinase levels were significantly lower (p < 0.001, and p = 0.004, respectively) in the BCAA group during and following resistance training. These findings suggest that short-term amino acid supplementation, which is high in BCAA, may produce a net anabolic hormonal profile while attenuating training-induced increases in muscle tissue damage. Athletes' nutrient intake, which periodically increases amino acid intake to reflect the increased need for recovery during periods of overreaching, may increase subsequent competitive performance while decreasing the risk of injury or illness.
Role of alpha-tocopherol in cardiopulmonary fitness in endurance athletes, cyclists.Patil SM, Chaudhuri D, Dhanakshirur GB.: Indian Journal of Physiology and Pharmacology, 2009 Oct-Dec 53(4):375-9. Department of Physiology, B.L.D.E.A.'s Shri B.M. Patil Medical College, Bijapur - 586 103. Exercise increases oxygen consumption and causes a disturbance of intracellular pro-oxidant-antioxidant homeostasis. Athletes are exposed to acute and chronic stress that may lead to increased generation of oxidative species. Hence oxidative stress increases in athletes. Administration of antioxidant like alpha-tocopherol as supplementation may reduce the cell damage caused due to oxidative stress. In the present study, our aim was to study the effects of alpha-tocopherol supplementation on the cardiopulmonary fitness in endurance athletes (cyclists) and non-athletes. Our study included 40 cyclists who were trained under District Youth Service & Sports Office. 40 controls were randomly selected from student group of B.L.D.E.A's Medical College. Alpha-tocopherol (Vitamin E) 200 mg/day for 21 days wasgiven to study group and placebo was given to placebo group. Various physiological parameters like heart rate, blood pressure, respiratory rate were recorded, for assessing cardiopulmonary fitness: Physical Fitness Index (PFI) and VO2 max ml/min/kg were recorded before and after supplementation of vitamin E in athletes, and were compared with placebo group before and after supplementation of placebo and also with non-athletes. The results obtained from present study indicate that antioxidant like alpha-tocopherol supplementation did not contribute significantly to improve the cardiopulmonary fitness of endurance athletes.
Circulatory collapse in bodybuilder during anaesthesiaRavn T, Afshari A, Nielsen JS.: Ugeskrift for laeger, 2010-07-19 172(29):2094-5. Hvidovre Hospital, Anaestesiologisk Afdeling, Denmark. The use of anabolic steroids is a growing problem in Denmark. The effects and side effects caused by anabolic steroids in relation to anaesthesia are poorly described. This article describes a case of circulatory collapse in a young bodybuilder during anaesthesia. The primary cause of the collapse remains undetermined, but different hypotheses are proposed based on previously published literature.
Effect of a proprietary protein supplement on recovery indices following resistance exercise in strength/power athletes.Hoffman JR, Ratamess NA, Tranchina CP, Rashti SL, Kang J, Faigenbaum AD.: Amino Acids, 2010, 38(3):771-8. Department of Health and Exercise Science, The College of New Jersey, PO Box 7718, Ewing, NJ 08628-0718, USA. The effect of 42 g of protein ingested pre- and post-exercise on recovery from an acute resistance exercise session was examined in 15 male strength/power athletes who were randomly divided into a supplement (SUP) or placebo (PL) group. Subjects reported to the Human Performance Laboratory (HPL) on four separate occasions (T1-T4). Maximal strength [one repetition-maximum (1-RM)] testing was performed during T1. During T2 subjects performed four sets of ten repetitions at 80% of their 1-RM in the squat, dead lift and barbell lunge exercises with 90 s of rest between each set. Blood draws occurred at baseline (BL), immediate and 15 min post-exercise to determine testosterone, cortisol and creatine kinase (CK) concentrations. Subjects reported back to the HPL 24 (T3) and 48 h (T4) post-exercise for a BL blood draw and to perform four sets of ten repetitions with 80% of 1-RM for the squat exercise only. No differences in the number of repetitions performed in the squat exercise were seen between the groups at T2. Relative to T2, PL performed significantly (P < 0.05) fewer repetitions than SUP at T3 and T4 (-9.5 +/- 5.5 repetitions vs. -3.3 +/- 3.6 during T3, respectively, and -10.5 +/- 8.2 repetitions vs. -2.3 +/- 2.9 repetitions during T4, respectively). No differences in hormonal measures were seen between the groups. CK concentrations were significantly (P < 0.05) elevated at T3 for both groups, but continued to elevate (P < 0.05) at T4 for PL only. No significant group differences were noted for CK at any time point. Results indicate that a proprietary protein SUP consumed before and after a resistance training session significantly contributes to improvements in exercise recovery 24 and 48 h post-exercise.
The effects of omega-3 supplementation on pulmonary function of young wrestlers during intensive training.Tartibian B, Maleki BH, Abbasi A:: Journal of Science and Medicine in Sport / Sports Medicine Australia, 2010, 13(2):281-6. Department of Physical Education and Sport Science, Urmia University, Iran. Babak The purpose of this study was to examine the effects of omega-3 supplementation on young wrestler's pulmonary function during intensive wrestling training. Forty healthy young male wrestlers participated in this study. The subjects were randomly divided into experimental (n=10), placebo (n=10), active control (n=10) and inactive control (n=10) groups. Participants in experimental, placebo and active control groups performed wrestling incremental training up to 95% of exercise MHR, three times a week, for 12 weeks. The inactive control group did not participate in any exercise training. Subjects in the experimental group were asked to consume omega-3 (1000 mg/day for 12 weeks), while those in placebo were refused any doses of omega-3. The pulmonary variables were measured at baseline and at the end of 12 weeks of training program. Results indicated that consuming omega-3 during 12 weeks training had a significantly positive effect on pulmonary variables such as FEV1, FVC, VC, MVV, FEF25-75, FIV1 (p=0.001), but no significant changes were observed in FEV1% (p=0.141) and FIV1% (p=0.117). The results of the present study suggest that consuming omega-3 during intensive wrestling training can improve pulmonary function of athletes during and in post-exercise.
Effect of zinc supplementation on antioxidant activity in young wrestlers.Kara E, Gunay M, Cicioglu I, Ozal M, Kilic M, Mogulkoc R, Baltaci AK.: Biological Trace Element Research, 201004 134(1):55-63. Faculty of Education, Department of Physical Fitness and Sport, Karabuk University, Karabuk, Turkey. This study aims to examine the effect of zinc supplementation on free-radical formation and antioxidant system in individuals who are actively engaged in wrestling as a sport. The study registered a total of 40 male subjects, of whom 20 were wrestlers and 20 were sedentary individuals. The subjects were equally allocated to four groups: group 1, zinc-supplemented sportsmen group; group 2, sportsmen group without supplementation; group 3, zinc-supplemented sedentary group; group 4, sedentary group without supplementation. Blood samples were collected from all subjects twice, once at the beginning of the study and once again at the end of 8-week procedures. The blood samples collected were analyzed to determine the levels of malondialdehyde (MDA), serum glutathione (GSH), serum glutathione peroxidase (GPx) activity, serum superoxide dismutase (SOD) activity (ELISA colorimetric method) and zinc (colorimetric method). No difference was found between MDA levels of the study groups in the beginning of the study. The highest MDA value at the end of the study was obtained in group 4 (p < 0.01). MDA levels in group 2 were established to be significantly higher than those in groups 1 and 3 (p < 0.01). GSH level, GPx, and SOD activities and zinc level measured in the beginning of the study were not different between groups. Measurements performed at the end of the study showed that groups 1 and 3 (zinc-supplemented groups) had the highest GSH level, GPx, and SOD activities and zinc level (p < 0.01). These parameters were not different in the groups without supplementation (groups 2 and 4). Results obtained at the end of the study indicate that zinc supplementation prevents production of free radicals by activating the antioxidant system. In conclusion, physiologic doses of zinc supplementation to athletes may beneficially contribute to their health and performance.
Post-exercise alcohol ingestion exacerbates eccentric-exercise induced losses in performance.Barnes MJ, Mündel T, Stannard SR .: European Journal of Applied Physiology, 201003 108(5):1009-14 Institute of Food, Nutrition, and Human Health, Massey University, Private Bag 11-222, Palmerston North, New Zealand. The effect of acute alcohol intake on muscular performance in both the exercising and non-exercising legs in the days following strenuous eccentric exercise was investigated to ascertain whether an interaction between post-exercise alcohol use and muscle damage causes an increase in damage-related weakness. Ten healthy males performed 300 maximal eccentric contractions of the quadriceps muscles of one leg on an isokinetic dynamometer. They then consumed either a beverage containing 1 g of ethanol per kg bodyweight ethanol (as vodka and orange juice; ALC) or a non-alcoholic beverage (OJ). At least 2 weeks later they performed an equivalent bout of eccentric exercise on the contralateral leg after which they consumed the other beverage. Measurement of peak and average peak isokinetic (concentric and eccentric) and isometric torque produced by the quadriceps of both exercising and non-exercising legs was made before and 36 and 60 h post-exercise. Greatest decreases in exercising leg performance were observed at 36 h with losses of 28.7, 31.9 and 25.9% occurring for OJ average peak isometric, concentric, and eccentric torques, respectively. However, average peak torque loss was significantly greater in ALC with the same performance measures decreasing by 40.9, 42.8 and 44.8% (all p < 0.05). Performance of the non-exercising leg did not change significantly under either treatment. Therefore, consumption of moderate amounts of alcohol after damaging exercise magnifies the loss of force associated with strenuous eccentric exercise. This weakness appears to be due to an interaction between muscle damage and alcohol rather than the systemic effects of acute alcohol consumption.
Effects of acute multinutrient supplementation on rugby union game performance and recovery.Minett G, Duffield R, Bird SP.: International Journal of Sports Physiology and performance 201003 5(1):27-41. School of Human Movement Studies, Charles Sturt University, Panorama Avenue, Bathurst, NSW, Australia. Purpose: To investigate the effects of an acute multinutrient supplement on game-based running performance, peak power output, anaerobic by-products, hormonal profiles, markers of muscle damage, and perceived muscular soreness before, immediately after, and 24 h following competitive rugby union games. Methods: Twelve male rugby union players ingested either a comprehensive multinutrient supplement (SUPP), [RE-ACTIVATE:01], or a placebo (PL) for 5 d. Participants then performed a competitive rugby union game (with global positioning system tracking), with associated blood draws and vertical jump assessments pre, immediately post and 24 h following competition. Results: SUPP ingestion resulted in moderate to large effects for augmented 1st half very high intensity running (VHIR) mean speed (5.9+/-0.4 vs 4.8+/-2.3 mxmin(-1); d=0.93). Further, moderate increases in 2nd half VHIR distance (137+/-119 vs 83+/-89 m; d=0.73) and VHIR mean speed (5.9+/-0.6 vs 5.3+/-1.7 mxmin(-1); d=0.56) in SUPP condition were also apparent. Postgame aspartate aminotransferase (AST; 44.1+/-11.8 vs 37.0+/-3.2 UL; d=1.16) and creatine kinase (CK; 882+/-472 vs 645+/-123 UL; d=0.97) measures demonstrated increased values in the SUPP condition, while AST and CK values correlated with 2nd half VHIR distance (r=-0.71 and r=-0.76 respectively). Elevated C-reactive protein (CRP) was observed postgame in both conditions; however, it was significantly blunted with SUPP (P=.05). Conclusions : These findings suggest SUPP may assist in the maintenance of VHIR during rugby union games, possibly via the buffering qualities of SUPP ingredients. However, correlations between increased work completed at very high intensities and muscular degradation in SUPP conditions, may mask any anticatabolic properties of the supplement.
Quercetin's effect on cycling efficiency and substrate utilization.Dumke CL, Nieman DC, Utter AC, Rigby MD, Quindry JC, Triplett NT, McAnulty SR, McAnulty LS.: Applied Physiology, Nutrition, and Metabolism = Physiologie Appliquée, Nutrition et Métabolisme, 2009, 34(6):993-1000. Department of Health and Human Perfomance, University of Montana, Missoula, MT 59812, USA. Previous evidence suggests that quercetin supplementation increases performance in humans. We examined the effects of 3 weeks of quercetin supplementation on fuel utilization, gross efficiency (GE), and perceived effort during 3 h of cycling over 3 successive days. Forty cyclists were randomized into quercetin and placebo groups and tested for maximal oxygen consumption (53.2 +/- 1.2 and 54.7 +/- 1.1 mL.kg(-1).min(-1)). For 3 weeks following maximal oxygen consumption testing, subjects supplemented either 1000 mg.day(-1) quercetin or placebo during normal training. Following supplementation, subjects cycled at 57% maximum power for 3 h, on 3 successive days, using their own bicycles fitted to CompuTrainer Pro Model trainers (RacerMate, Seattle, Wash.). Metabolic measurements were taken every 30 min for each 3-h ride. Muscle biopsies obtained from the vastus lateralis immediately pre-exercise and postexercise on days 1 and 3 were analyzed for muscle glycogen content. Power output remained constant for all 3 exercise trials, but significant decreases over time were measured for GE, cadence, respiratory exchange ratio, blood glucose, and muscle glycogen. Significant increases were measured for heart rate and volume of oxygen consumption over time. No quercetin treatment effect was observed for any of the outcome measures in this study. These data indicate that GE is reduced during an exhausting 3-h bout of exercise. However, quercetin did not significantly affect any outcomes in these already well-trained subjects.
Medication use by athletes during the Athens 2004 Paralympic GamesC Tsitsimpikou, A Jamurtas, K Fitch, P Papalexis, K Tsarouhas.: Br J Sports Med 2009;43:1062-1066. Objective: To examine the use of food supplements and pharmaceutical preparations by elite Paralympic athletes. Design: Survey study. Setting: Athens 2004 Paralympic Games. Participants: Data obtained from two sources: (i) athletes’ declaration of intake of drugs/supplements recorded on the Doping Control Official Record during sample collection for doping control; (ii) athletes’ application forms for granting of a therapeutic use exemption. Main outcome measures: Classification of declared food supplements according to the active ingredient and medications according to therapeutic actions and active compounds. Results: 64.2% of the athletes tested for doping control declared use of medications or food supplements, and 81.3% of these athletes declared intake of fewer than four preparations. Non-invasive routes of administration dominated. Food supplements (42.1%) were popular, and drugs used to treat several pathological conditions noted. Non-steroidal anti-inflammatory agents and analgesics were commonly used (9.8% and 5.6%, respectively). The prevalence of inhaled β2-agonist use (4.8%) was higher than expected and exceeded that at the Athens Olympic Games. Conclusions: This review, the first to examine elite Paralympic athletes, shows a more rational approach to the use of medication and food supplements, but a similar consumption pattern to that of athletes at the Athens Olympic Games. Because of the dearth of such studies, consumption trends among Paralympic athletes remain unclear. The need to counsel athletes with disabilities on their nutritional needs is confirmed, and close monitoring by healthcare professionals is recommended. Effects of resistance training combined with antioxidant supplementation on fat-free mass and insulin sensitivity in healthy elderly subjects.
Bobeuf F, Labonté M, Khalil A, Dionne IJ.: Diabetes Research and Clinical Practice, 87(1):e1-3, 2009. Research Centre on Aging, University of Sherbrooke, Sherbrooke, QC, Canada.
The aim of this study was to verify the effect of resistance training and antioxidant supplementation on fat-free mass (FFM) and insulin sensitivity (IS). The results demonstrate that 6 months of resistance training combined with antioxidant supplementation significantly increased FFM without concomitant significant improvement in IS in older adults.
|