Information about behavior of energy intake in ultra-endurance cyclists during a 24-hour team relay race is scarce. The nutritional strategy during such an event is an important factor which athletes should plan carefully before the race. The purpose of this study was to examine and compare the nutritional intake of ultra-endurance cyclists during a 24-hour team relay race with the current nutritional guidelines for endurance events. Additionally, we analyzed the relationship among the nutritional and performance variables.
Using a observational design, nutritional intake of eight males (mean ± SD: 36.7 ± 4.7 years; 71.6 ± 4.9 kg; 174.6 ± 7.3 cm; BMI 23.5 ± 0.5 kg/m2) participating in a 24-hour team relay cycling race was assessed. All food and fluid intake by athletes were weighed and recorded. Additionally, distance and speed performed by each rider were also recorded. Furthermore, before to the race, all subjects carried out an incremental exercise test to determine two heart rate-VO2 regression equations which were used to estimate the energy expenditure.
The mean ingestion of macronutrients during the event was 943 ± 245 g (13.1 ± 4.0 g/kg) of carbohydrates, 174 ± 146 g (2.4 ± 1.9 g/kg) of proteins and 107 ± 56 g (1.5 ± 0.7 g/kg) of lipids, respectively. This amount of nutrients reported an average nutrient intake of 22.8 ± 8.9 MJ which were significantly lower compared with energy expenditure 42.9 ± 6.8 MJ (P = 0.012). Average fluid consumption corresponded to 10497 ± 2654 mL. Mean caffeine ingestion was 142 ± 76 mg. Additionally, there was no relationship between the main nutritional variables (i.e. energy intake, carbohydrates, proteins, fluids and caffeine ingestion) and the main performance variables (i.e. distance and speed).
A 24-hour hours cycling competition in a team relay format elicited high energy demands which were not compensated by energy intake of the athletes despite that dietary consumption of macronutrients did not differ to the nutritional guidelines for longer events.
To assess the prevalence of exercise-associated hyponatremia (EAH) in two 24-hour mountain bike (MTB) (R1,R2), one 24-hour running (R3) and one multi-stage MTB (R4) races held in the Czech Republic in a cluster of four cross-sectional studies.
In 27 ultra-mountain bikers (ultra-MTBers), 12 ultra-runners, and 14 multi-stage MTBers, fluid intake, changes (Delta) in body mass, hematocrit, plasma volume, plasma [Na+], plasma [K+], plasma osmolality, urine [Na+], urine [K+], urine specific gravity, urine osmolality, K+/Na+ ratio in urine, transtubular potassium gradient and glomerular filtration rate were measured and calculated. The use of non-steroidal anti-inflammatory drugs and symptoms of EAH were recorded using post-race questionnaires.
Of the 53 finishers, three (5.7%) developed post-race EAH, thereof one (3.7%) ultra-MTBer, one (8.3%) ultra-runner and one (7.1%) multi-stage MTBer. Plasma [Na+] decreased significantly (p < 0.001) only in R4. Urine osmolality (R1, R3, R4 p < 0.001; R2 p < 0.05) and glomerular filtration rate (p < 0.001) increased, and body mass decreased in all races (p < 0.05). Delta body mass was inversely related to the number of kilometers achieved (p < 0.001) in R2 where better ultra-MTBers tended to lose more weight. Delta body mass (p < 0.001) and %Delta body mass (p = 0.05) were positively related to lower post-race plasma [Na+] in R3 that was associated with increased loss in body mass. Fluid intake was positively related to race performance in R1 and R2 (R1: p = 0.04; R2: p = 0.01) where ultra-MTBers in R1 and R2 who drank more finished ahead of those who drank less. Post-race plasma [Na+] was negatively associated with race performance in ultra-MTBers in R2 (p < 0.05), similarly ultra-runners in R3 (p < 0.05) where finishers with more kilometres had lower post-race plasma [Na+].
The prevalence of EAH in the Czech Republic was no higher compared to existing reports on ultra-endurance athletes in other countries. Lower plasma [Na+] and development of EAH may be attributed to overdrinking, a pituitary secretion of vasopressin, an impaired mobilization of osmotically inactive sodium stores, and/or an inappropriate inactivation of osmotically active sodium.
Recently, slow release tablets have been developed to prolong energy release throughout the day. The efficacy of the delivery of slow-release caffeine alone is fairly well documented; however, an assessment of safety and tolerability of prolonged use of slow-release energy supplements is lacking. Therefore the objective of this study was to investigate the effect of daily ingestion of a slow-release energy supplement for 28 days on blood chemistry and resting cardiovascular measures in healthy men and women.
Forty healthy individuals (20 males, 20 females; age: 22.73 ± 3.06 years; height: 171.68 ± 10.45 cm; mass: 74.49 ± 15.51 kg; BMI: 25.08 ± 3.66 (kg • m(2)) (-1)) participated in this randomized, double-blind, placebo controlled study. Following a 12-hour fast, participants reported for pre-testing. Testing consisted of resting heart rate (RHR) and blood pressure (BP) measures, followed by assessment of metabolic blood chemistry, blood lipids and complete cell counts. Participants then supplemented with either Energize™ (SUPP) or placebo (PL) for 28 days. Post-testing occurred 24-hours after ingestion of the final dose and consisted of the same protocol at the same time of day as pre-testing.
No significant changes in outcome measures were observed. A significant difference between groups was observed for plasma glucose concentrations; however, follow-up testing revealed that pre- to post-supplementation changes were not significant for either SUPP or PL. All variables remained within normal adult reference ranges. No adverse events were reported.
These findings indicate that 28 consecutive days ingestion of a slow release energy supplement containing caffeine in caffeine users is both safe and tolerable.
The consumption of dietary protein is important for resistance-trained individuals. It has been posited that intakes of 1.4 to 2.0 g/kg/day are needed for physically active individuals. Thus, the purpose of this investigation was to determine the effects of a very high protein diet (4.4 g/kg/d) on body composition in resistance-trained men and women.
Thirty healthy resistance-trained individuals participated in this study (mean ± SD; age: 24.1 ± 5.6 yr; height: 171.4 ± 8.8 cm; weight: 73.3 ± 11.5 kg). Subjects were randomly assigned to one of the following groups: Control (CON) or high protein (HP). The CON group was instructed to maintain the same training and dietary habits over the course of the 8 week study. The HP group was instructed to consume 4.4 grams of protein per kg body weight daily. They were also instructed to maintain the same training and dietary habits (e.g. maintain the same fat and carbohydrate intake). Body composition (Bod Pod®), training volume (i.e. volume load), and food intake were determined at baseline and over the 8 week treatment period.
The HP group consumed significantly more protein and calories pre vs post (p < 0.05). Furthermore, the HP group consumed significantly more protein and calories than the CON (p < 0.05). The HP group consumed on average 307 ± 69 grams of protein compared to 138 ± 42 in the CON. When expressed per unit body weight, the HP group consumed 4.4 ± 0.8 g/kg/d of protein versus 1.8 ± 0.4 g/kg/d in the CON. There were no changes in training volume for either group. Moreover, there were no significant changes over time or between groups for body weight, fat mass, fat free mass, or percent body fat.
Consuming 5.5 times the recommended daily allowance of protein has no effect on body composition in resistance-trained individuals who otherwise maintain the same training regimen. This is the first interventional study to demonstrate that consuming a hypercaloric high protein diet does not result in an increase in body fat.
The purpose of the present study was to evaluate the effects of PCSO-524®, a marine oil lipid and n-3 LC PUFA blend, derived from New Zealand green- lipped mussel (Perna canaliculus), on markers of muscle damage and inflammation following muscle damaging exercise in untrained men.
Thirty two untrained male subjects were randomly assigned to consume 1200 mg/d of PCSO- 524® (a green-lipped mussel oil blend) or placebo for 26 d prior to muscle damaging exercise (downhill running), and continued for 96 h following the muscle damaging exercise bout. Blood markers of muscle damage (skeletal muscle slow troponin I, sTnI; myoglobin, Mb; creatine kinase, CK), and inflammation (tumor necrosis factor, TNF-α), and functional measures of muscle damage (delayed onset muscle soreness, DOMS; pressure pain threshold, PPT; knee extensor joint range of motion, ROM; isometric torque, MVC) were assessed pre- supplementation (baseline), and multiple time points post-supplementation (before and after muscle damaging exercise). At baseline and 24 h following muscle damaging exercise peripheral fatigue was assessed via changes in potentiated quadriceps twitch force (∆Qtw,pot) from pre- to post-exhaustive cycling ergometer test in response to supra-maximal femoral nerve stimulation.
Compared to placebo, supplementation with the green-lipped mussel oil blend significantly attenuated (p < 0.05) sTnI and TNF-α at 2, 24, 48, 72 and 96 h., Mb at 24, 48, 72, 96 h., and CK-MM at all-time points following muscle damaging exercise, significantly reduced (p < 0.05) DOMS at 72 and 96 h post-muscle damaging exercise, and resulted in significantly less strength loss (MVC) and provided a protective effect against joint ROM loss at 96 h post- muscle damaging exercise. At 24 h after muscle damaging exercise perceived pain was significantly greater (p < 0.05) compared to baseline in the placebo group only. Following muscle damaging exercise ∆Qtw,pot was significantly less (p < 0.05) on the green-lipped mussel oil blend compared to placebo.
Supplementation with a marine oil lipid and n-3 LC PUFA blend (PCSO-524®), derived from the New Zealand green lipped mussel, may represent a useful therapeutic agent for attenuating muscle damage and inflammation following muscle damaging exercise.
Ageing is associated with a significant reduction in skeletal muscle carnosine which has been linked with a reduction in the buffering capacity of muscle and in theory, may increase the rate of fatigue during exercise. Supplementing beta-alanine has been shown to significantly increase skeletal muscle carnosine. The purpose of this study, therefore, was to examine the effects of ninety days of beta-alanine supplementation on the physical working capacity at the fatigue threshold (PWCFT) in elderly men and women.
Using a double-blind placebo controlled design, twenty-six men (n = 9) and women (n = 17) (age +/- SD = 72.8 +/- 11.1 yrs) were randomly assigned to either beta-alanine (BA: 800 mg x 3 per day; n = 12; CarnoSyntrade mark) or Placebo (PL; n = 14) group. Before (pre) and after (post) the supplementation period, participants performed a discontinuous cycle ergometry test to determine the PWCFT.
Significant increases in PWCFT (28.6%) from pre- to post-supplementation were found for the BA treatment group (p < 0.05), but no change was observed with PL treatment. These findings suggest that ninety days of BA supplementation may increase physical working capacity by delaying the onset of neuromuscular fatigue in elderly men and women.
We suggest that BA supplementation, by improving intracellular pH control, improves muscle endurance in the elderly. This, we believe, could have importance in the prevention of falls, and the maintenance of health and independent living in elderly men and women.
Deep oceans have been suggested as a possible site where the origin of life occurred. Along with this theoretical lineage, experiments using components from deep ocean water to recreate life is underway. Here, we propose that if terrestrial organisms indeed evolved from deep oceans, supply of deep ocean mineral water (DOM) to humans, as a land creature, may replenish loss of molecular complexity associated with evolutionary sea-to-land migration.
We conducted a randomized, double-blind, placebo-controlled crossover human study to evaluate the effect of DOM, taken from a depth of 662 meters off the coast of Hualien, Taiwan, on time of recovery from a fatiguing exercise conducted at 30°C.
The fatiguing exercise protocol caused a protracted reduction in aerobic power (reduced VO2max) for 48 h. However, DOM supplementation resulted in complete recovery of aerobic power within 4 h (P < 0.05). Muscle power was also elevated above placebo levels within 24 h of recovery (P < 0.05). Increased circulating creatine kinase (CK) and myoglobin, indicatives of exercise-induced muscle damage, were completely eliminated by DOM (P < 0.05) in parallel with attenuated oxidative damage (P < 0.05).
Our results provide compelling evidence that DOM contains soluble elements, which can increase human recovery following an exhaustive physical challenge.
Substances with performance enhancing properties appear on a continuum, ranging from prohibited performance enhancing drugs (PED) through dietary supplements to functional foods (FF). Anti-doping messages designed to dissuade athletes from using PEDs have been typically based on moralising sport competition and/or employing scare campaigns with focus on the negative consequences. Campaigns offering comparable and acceptable alternatives are nonexistent, nor are athletes helped in finding these for themselves. It is timely that social marketing strategies for anti-doping prevention and intervention incorporate media messages that complement the existing approaches by promoting comparable and acceptable alternatives to doping. To facilitate this process, the aim of this study was to ascertain whether a single exposure knowledge-based information intervention led to increased knowledge and subsequently result in changes in beliefs and automatic associations regarding performance enhancements.
In a repeated measure design, 115 male recreational gym users were recruited and provided with a brief information pamphlet on nitrite/nitrate and erythropoietin as a comparison. Measures of knowledge, beliefs and automatic associations were taken before and after the intervention with at least 24 hours between the two assessments. The psychological tests included explicit measures of beliefs and cognitive attitudes toward FF and PED using a self-reported questionnaire and computerised assessments of automatic associations using the modified and shortened version of the Implicit Association Test.
The information based intervention significantly increased knowledge (p < 0.001), changed explicit beliefs in specific FF (p < 0.001) and shifted the automatic association of FF with health to performance (p < 0.001). Explicitly expressed beliefs and automatic associations appear to be independent.
Evidence was found that even a single exposure to a persuasive positive message can lead to belief change and can create new or alter existing associations - but only in the specific domain. Interventions to change outcome expectations in a positive way could be a rewarding avenue for anti-doping. Effective social marketing campaigns for drug free sport should follow appropriate market segmentation and use targeted messages via promoting the natural form as opposed to the purified form of the main active ingredient.
In the present study, we determined the effects of HX108-CS (mixed extract of Schisandra chinensis and Chaenomeles sinensis) supplementation on lactate accumulation and endurance capacity. Furthermore, we examined CK (creatine kinase), LDH (lactate dehydrogenase) activity to determine whether the HX108-CS affected markers of skeletal muscle injury in vivo and in vitro.
Exercise capacity was measured by an exhaustive swimming test using ICR mice divided into four groups; one group received distilled water (DW) (Control group, n = 10), and the other groups received three different dosages of HX108-CS (10, 50 and 100 mg/kg, n = 10 per group) solution in water orally. Then, for the time-dependent measurements of blood lactate, CK, and LDH, Sprague–Dawley rats were divided into two groups; one received DW (Control group, n = 10), and the other group received HX108-CS (100 mg/kg, n = 10) solution in the same way as mice. Before the exercise test, the animals were given either DW or HX108-CS for 2 weeks. High-intensity treadmill exercise was performed for 30 minutes. Blood samples were collected and analyzed during and after exercise. For the in vitro experiment, C2C12 cells were treated with HX108-CS to examine its effect on lactate production, CK, and LDH activity.
Blood lactate concentration was significantly lowered immediately after treadmill exercise in HX108-CS group; however, there were no significant differences in activities of CK and LDH between HX108-CS and control during treadmill exercise and recovery phase. Furthermore, treatment with 100 mg/kg of HX108-CS led to a significant increase in the time to exhaustion in swimming test, and concurrently blood lactate concentration was significantly decreased in 50 and 100 mg/kg treated group. Moreover, our results of in vitro experiment showed that HX108-CS suppressed lactate production, CK, and LDH activity in a dose-dependent manner.
These results suggest that supplementation with HX108-CS may enhance exercise capacity by lowering lactate accumulation. This may in part be related to an amelioration of skeletal muscle injury.
beta-Alanine (betaA) has been shown to improve performance during cycling. This study was the first to examine the effects of betaA supplementation on the onset of blood lactate accumulation (OBLA) during incremental treadmill running.
Seventeen recreationally-active men (mean +/- SE 24.9 +/- 4.7 yrs, 180.6 +/- 8.9 cm, 79.25 +/- 9.0 kg) participated in this randomized, double-blind, placebo-controlled pre/post test 2-treatment experimental design. Subjects participated in two incremental treadmill tests before and after 28 days of supplementation with either betaA (6.0 g.d-1)(betaA, n = 8) or an equivalent dose of Maltodextrin as the Placebo (PL, n = 9). Heart rate, percent heart rate maximum (%HRmax), %VO2max@OBLA (4.0 mmol.L-1 blood lactate concentration) and VO2max (L.min-1) were determined for each treadmill test. Friedman test was used to determine within group differences; and Mann-Whitney was used to determine between group differences for pre and post values (p < 0.05).
The betaA group experienced a significant rightward shift in HR@OBLA beats.min-1 (p < 0.01) pre/post (161.6 +/- 19.2 to 173.6 +/- 9.9) but remained unchanged in the PL group (166.8 +/- 15.8 to 169.6 +/- 16.1). The %HRmax@OBLA increased (p < 0.05) pre/post in the betaA group (83.0% +/- 9.7 to 88.6% +/- 3.7) versus no change in the PL group (86.3 +/- % 4.8 to 87.9% +/- 7.2). The %VO2max@OBLA increased (p < 0.05) in the betaA group pre/post (69.1 +/- 11.0 to 75.6 +/- 10.7) but remained unchanged in the PL group (73.3 +/- 7.3 to 74.3 +/- 7.3). VO2max (L.min-1) decreased (p < 0.01) in the betaA group pre/post (4.57 +/- 0.8 to 4.31 +/- 0.8) versus no change in the PL group (4.04 +/- 0.7 to 4.18 +/- 0.8). Body mass kg increased (p < 0.05) in the betaA group pre/post (77.9 +/- 9.0 to 78.3 +/- 9.3) while the PL group was unchanged (80.6 +/- 9.1 to 80.4 +/- 9.0).
betaA supplementation for 28 days enhanced sub-maximal endurance performance by delaying OBLA. However, betaA supplemented individuals had a reduced aerobic capacity as evidenced by the decrease in VO2max values post supplementation.
Melatonin and resistance exercise alone have been shown to increase the levels of growth hormone (GH). The purpose of this study was to determine the effects of ingestion of a single dose of melatonin and heavy resistance exercise on serum GH, somatostatin (SST), and other hormones of the GH/insulin-like growth factor 1 (IGF-1) axis. Physically active males (n = 30) and females (n = 30) were randomly assigned to ingest either a melatonin supplement at 0.5 mg or 5.0 mg, or 1.0 mg of dextrose placebo. After a baseline blood sample, participants ingested the supplement and underwent blood sampling every 15 min for 60 min, at which point they underwent a single bout of resistance exercise with the leg press for 7 sets of 7 reps at 85% 1-RM. After exercise, participants provided additional blood samples every 15 min for a total of 120 min. Serum free GH, SST, IGF-1, IGFBP-1, and IGFBP-3 were determined with ELISA. Data were evaluated as the peak pre- and post-exercise values subtracted from baseline and the delta values analyzed with separate three-way ANOVA (p < 0.05). In males, when compared to placebo, 5.0 mg melatonin caused GH to increase (p = 0.017) and SST to decrease prior to exercise (p = 0.031), whereas both 0.5 and 5.0 mg melatonin were greater than placebo after exercise (p = 0.045) and less than placebo for SST. No significant differences occurred for IGF-1; however, males were shown to have higher levels of IGFBP-1 independent of supplementation (p = 0.004). The 5.0 mg melatonin dose resulted in higher IGFBP-3 in males (p = 0.017). In conclusion, for males 5.0 mg melatonin appears to increase serum GH while concomitantly lowering SST levels; however, when combined with resistance exercise both melatonin doses positively impacts GH levels in a manner not entirely dependent on SST.
An increase in exercise intensity is one of the many ways in which oxidative stress and free radical production has been shown to increase inside our cells. Effective regulation of the cellular balance between oxidation and antioxidation is important when considering cellular function and DNA integrity as well as the signal transduction of gene expression. Many pathological states, such as cancer, Parkinson's disease, and Alzheimer's disease have been shown to be related to the redox state of cells. In an attempt to minimize the onset of oxidative stress, supplementation with various known antioxidants has been suggested. Glutathione and N-acetyl-cysteine (NAC) are antioxidants which are quite popular for their ability to minimize oxidative stress and the downstream negative effects thought to be associated with oxidative stress. Glutathione is largely known to minimize the lipid peroxidation of cellular membranes and other such targets that is known to occur with oxidative stress. N-acetyl-cysteine is a by-product of glutathione and is popular due to its cysteine residues and the role it has on glutathione maintenance and metabolism. The process of oxidative stress is a complicated, inter-twined series of events which quite possibly is related to many other cellular processes. Exercise enthusiasts and researchers have become interested in recent years to identify any means to help minimize the detrimental effects of oxidative stress that are commonly associated with intense and unaccustomed exercise. It is possible that a decrease in the amount of oxidative stress a cell is exposed to could increase health and performance.
BACKGROUND: The purpose was to investigate the effects of one dose of NaHCO3 per day for five consecutive days on cycling time-to-exhaustion (Tlim) at 'Critical Power' (CP) and acid-base parameters in endurance athletes.
METHODS: Eight trained male cyclists and triathletes completed two exercise periods in a randomized, placebo-controlled, double-blind interventional crossover investigation. Before each period, CP was determined. Afterwards, participants completed five constant-load cycling trials at CP until volitional exhaustion on five consecutive days, either after a dose of NaHCO3 (0.3 g·kg-1 body mass) or placebo (0.045 g·kg-1 body mass NaCl).
RESULTS: Average Tlim increased by 23.5% with NaHCO3 supplementation as compared to placebo (826.5 ± 180.1 vs. 669.0 ± 167.2 s; P = 0.001). However, there was no time effect for Tlim (P = 0.375). [HCO3-] showed a main effect for condition (NaHCO3: 32.5 ± 2.2 mmol·l-1; placebo: 26.2 ± 1.4 mmol·l-1; P < 0.001) but not for time (P = 0.835). NaHCO3 supplementation resulted in an expansion of plasma volume relative to placebo (P = 0.003).
CONCLUSIONS: The increase in Tlim was accompanied by an increase in [HCO3-], suggesting that acidosis might be a limiting factor for exercise at CP. Prolonged NaHCO3 supplementation did not lead to a further increase in [HCO3-] due to the concurrent elevation in plasma volume. This may explain why Tlim remained unaltered despite the prolonged NaHCO3 supplementation period. Ingestion of one single NaHCO3 dose per day before the competition during multiday competitions or tournaments might be a valuable strategy for performance enhancement.
TRIAL REGISTRATION: Trial registration: ClinicalTrials.gov Identifier NCT01621074.
A randomized, single-blinded, placebo-controlled, parallel design study was used to examine the effects of a pre-workout supplement combined with three weeks of high-intensity interval training (HIIT) on aerobic and anaerobic running performance, training volume, and body composition.
Twenty-four moderately-trained recreational athletes (mean +/- SD age = 21.1 +/- 1.9 yrs; stature = 172.2 +/- 8.7 cm; body mass = 66.2 +/- 11.8 kg, VO2max = 3.21 +/- 0.85 l.min-1, percent body fat = 19.0 +/- 7.1%) were assigned to either the active supplement (GT, n = 13) or placebo (PL, n = 11) group. The active supplement (Game Time(R), Corr-Jensen Laboratories Inc., Aurora, CO) was 18 g of powder, 40 kcals, and consisted of a proprietary blend including whey protein, cordyceps sinensis, creatine, citrulline, ginseng, and caffeine. The PL was also 18 g of powder, 40 kcals, and consisted of only maltodextrin, natural and artificial flavors and colors. Thirty minutes prior to all testing and training sessions, participants consumed their respective supplements mixed with 8-10 oz of water. Both groups participated in a three-week HIIT program three days per week, and testing was conducted before and after the training. Cardiovascular fitness (VO2max) was assessed using open circuit spirometry (Parvo-Medics TrueOne(R) 2400 Metabolic Measurement System, Sandy, UT) during graded exercise tests on a treadmill (Woodway, Pro Series, Waukesha, WI). Also, four high-speed runs to exhaustion were conducted at 110, 105, 100, and 90% of the treadmill velocity recorded during VO2max, and the distances achieved were plotted over the times-to-exhaustion. Linear regression was used to determine the slopes (critical velocity, CV) and y-intercepts (anaerobic running capacity, ARC) of these relationships to assess aerobic and anaerobic performances, respectively. Training volumes were tracked by summing the distances achieved during each training session for each subject. Percent body fat (%BF) and lean body mass (LBM) were assessed with air-displacement plethysmography (BOD POD(R), Life Measurement, Inc., Concord, CA).
Both GT and PL groups demonstrated a significant (p = 0.028) increase in VO2max from pre- to post-training resulting in a 10.3% and 2.9% improvement, respectively. CV increased (p = 0.036) for the GT group by 2.9%, while the PL group did not change (p = 0.256; 1.7% increase). ARC increased for the PL group by 22.9% and for the GT group by 10.6%. Training volume was 11.6% higher for the GT versus PL group (p = 0.041). %BF decreased from 19.3% to 16.1% for the GT group and decreased from 18.0% to 16.8% in the PL group (p = 0.178). LBM increased from 54.2 kg to 55.4 kg (p = 0.035) for the GT group and decreased from 52.9 kg to 52.4 kg in the PL group (p = 0.694).
These results demonstrated improvements in VO2max, CV, and LBM when GT is combined with HIIT. Three weeks of HIIT alone also augmented anaerobic running performance, VO2max and body composition.
Previous studies have evaluated the effectiveness of branched-chain amino acid (BCAA) supplementation for preventing delayed onset muscle soreness (DOMS) and muscle damage induced by eccentric exercise, their findings have been inconclusive. Since taurine has anti-inflammatory and anti-oxidative effects, the present study investigated the combined effect of BCAA and taurine on DOMS and muscle damage.
Thirty-six untrained male subjects (22.5 +/- 3.8 years) were assigned to four groups (placebo + placebo [placebo], BCAA + placebo, placebo + taurine, and BCAA + taurine [combined]) and given a combination of 3.2 g BCAA (or placebo) and 2.0 g taurine (or placebo), three times a day, for two weeks prior to and three days after eccentric elbow flexor exercises. DOMS and muscle damage in the biceps brachii were subjectively and objectively evaluated using the visual analogue scale (VAS), upper arm circumference (CIR), and blood parameters (creatine kinase, lactate dehydrogenase [LDH], aldolase, and 8-hydroxydeoxyguanosine [8-OHdG]).
In the combined group, VAS and 8-OHdG two days after exercise, CIR two and three days after exercise and LDH from one to three days after exercise were significant lower than the placebo group. The area under the curve from before exercise to four days later for CIR, LDH, and aldolase was also significant lower in the combined group than in the placebo group.
A combination of 3.2 g BCAA and 2.0 g taurine, three times a day, for two weeks prior to and three days after exercise may be a useful nutritional strategy for attenuating exercise-induced DOMS and muscle damage.
It is well documented that exercise-induced muscle damage (EIMD) decreases muscle function and causes soreness and discomfort. Branched-chain amino acid (BCAA) supplementation has been shown to increase protein synthesis and decrease muscle protein breakdown, however, the effects of BCAAs on recovery from damaging resistance training are unclear. Therefore, the aim of this study was to examine the effects of a BCAA supplementation on markers of muscle damage elicited via a sport specific bout of damaging exercise in trained volunteers.
Twelve males (mean ± SD age, 23 ± 2 y; stature, 178.3 ± 3.6 cm and body mass, 79.6 ± 8.4 kg) were randomly assigned to a supplement (n = 6) or placebo (n = 6) group. The damaging exercise consisted of 100 consecutive drop-jumps. Creatine kinase (CK), maximal voluntary contraction (MVC), muscle soreness (DOMS), vertical jump (VJ), thigh circumference (TC) and calf circumference (CC) were measured as markers of muscle damage. All variables were measured immediately before the damaging exercise and at 24, 48, 72 and 96 h post-exercise.
A significant time effect was seen for all variables. There were significant group effects showing a reduction in CK efflux and muscle soreness in the BCAA group compared to the placebo (P<0.05). Furthermore, the recovery of MVC was greater in the BCAA group (P<0.05). The VJ, TC and CC were not different between groups.
The present study has shown that BCAA administered before and following damaging resistance exercise reduces indices of muscle damage and accelerates recovery in resistance-trained males. It seems likely that BCAA provided greater bioavailablity of substrate to improve protein synthesis and thereby the extent of secondary muscle damage associated with strenuous resistance exercise. Clinical Trial Registration Number: NCT01529281.
Previous animal study has shown that supplementation with silk amino acid hydrolysate (SAA) increases stamina in mice. The presented study was the first formal evaluation of the influence of SAA supplementation on parameters defining physiological fitness level in humans.
It was a randomized controlled trial with a parallel-group design on elite male fin-swimmers. The experimental group was supplemented with 500 mg of SAA per kg of body mass, dissolved in 250 ml of a Carborade Drink®; the control group with Carborade Drink® alone; 3 times a day, 30 minutes prior to the training session.
Changes discerned in the experimental group were more pronounced than those observed in the control group. For example, the change in the serum lactic acid concentration observed in the experimental group was sevenfold less than in the control group [21.8 vs. -3.7 L% for the control and experimental groups, respectively]. An analysis of a lactate profile as a function of a maximal swimming velocity exposed a statistically significant positive shift in the swimming velocity of 0.05 m/s, at the lactate concentration of 4 mmol/L in the experimental group. There was also a positive, although statistically insignificant, increase of 2.6 L% in serum testosterone levels in the experimental group.
This study showed that a 12-day SAA supplementation combined with an extensive and rigorous training schedule was sufficient to increase an aerobic stamina. However, this phenomenon was associated with an augmented level of muscular damage (an increased level of creatine phosphokinase in the experimental group).
Experimental studies suggest that mineral waters with high concentrations of calcium and bicarbonate can impact acid-base balance. The purpose of this study was to test the effect on acid-base balance and specific urine gravity, of a bicarbonate calcic mineral water (Acqua Lete®) compared to a minimally mineralized water.
88 amateur male athletes underwent two experimental trials with a modified Wingate test: the first was carried out without hydration (Control Test, Test C, n = 88); the second was carried out after one week of controlled hydration (Test with hydration, Test H, n = 88), with 1.5 L/day of a very low mineral content water (Group A, n = 44) or 1.5 L/day of Acqua Lete® (Group B, n = 44). Measure of body temperature, bioimpedance analysis, muscular ultrasound, and urinalysis were taken before (t0), immediately after (t1), 5' (t2), and 30' (t3) after exercise.
Hydration results in a decreased core temperature; muscular ultrasound showed increased muscle thickness after exercise related to content of body water. Regarding urinalysis, in test H, we found in both groups after exercise a significant decrease of specific urine gravity with significantly lower levels in Group B. We also found a significant increase of pH in the same Group B.
In conclusion all the athletes hydrated with Acqua Lete® showed a positive impact on hydration status after anaerobic exercise with significant decrease of specific urine gravity and a positive effect on pH.
Oral intake of a specific extract of Opuntia ficus-indica cladode and fruit skin (OpunDiaTM) (OFI) has been shown to increase serum insulin concentration while reducing blood glucose level for a given amount of glucose ingestion after an endurance exercise bout in healthy young volunteers. However, it is unknown whether OFI-induced insulin stimulation after exercise is of the same magnitude than the stimulation by other insulinogenic agents like leucine as well as whether OFI can interact with those agents. Therefore, the aims of the present study were: 1) to compare the degree of insulin stimulation by OFI with the effect of leucine administration; 2) to determine whether OFI and leucine have an additive action on insulin stimulation post-exercise.
Eleven subjects participated in a randomized double-blind cross-over study involving four experimental sessions. In each session the subjects successively underwent a 2-h oral glucose tolerance test (OGTT) after a 30-min cycling bout at ~70% VO2max. At t0 and t60 during the OGTT, subjects ingested 75g glucose and capsules containing either 1) a placebo; 2) 1000mg OFI; 3) 3g leucine; 4) 1000mg OFI + 3g leucine. Blood samples were collected before and at 30-min intervals during the OGTT for determination of blood glucose and serum insulin.
Whereas no effect of leucine was measured, OFI reduced blood glucose at t90 by ~7% and the area under the glucose curve by ~15% and increased serum insulin concentration at t90 by ~35% compared to placebo (P<0.05). From t60 to the end of the OGTT, serum insulin concentration was higher in OFI+leucine than in placebo which resulted in a higher area under the insulin curve (+40%, P<0.05).
Carbohydrate-induced insulin stimulation post-exercise can be further increased by the combination of OFI with leucine. OFI and leucine could be interesting ingredients to include together in recovery drinks to resynthesize muscle glycogen faster post-exercise. Still, it needs to be confirmed that such nutritional strategy effectively stimulates post-exercise muscle glycogen resynthesis.
The purpose of this placebo-controlled, double-blind cross-over study was to compare the effects of two commercially available soft drinks on metabolic rate.
After giving informed consent, twenty healthy men and women were randomly assigned to ingest 12 ounces of Celsiustrade mark and, on a separate day, 12 ounces of Diet Coke(R). All subjects completed both trials using a randomized, counterbalanced design. Metabolic rate (via indirect calorimetry) and substrate oxidation (via respiratory exchange ratio) were measured at baseline (pre-ingestion) and at the end of each hour for 3 hours post-ingestion.
Two-way ANOVA revealed a significant interaction (p < 0.001) between trials in metabolic rate. Scheffe post-hoc testing indicated that metabolic rate increased by 13.8% (+ 0.6 L/min, p < 0.001) 1 hr post, 14.4% (+0.63 L/min, p < 0.001) 2 hr post, and 8.5% (+0.37 L/min, p < 0.004) 3 hr post Celsiustrade mark ingestion. In contrast, small (~4-6%) but statistically insignificant increases in metabolic rate were noted following Diet Coke(R) ingestion. No differences in respiratory exchange ratio were noted between trials.
These preliminary findings indicate Celsiustrade mark has thermogenic properties when ingested acutely. The effects of repeated, chronic ingestion of Celsiustrade mark on body composition are unknown at this time.
The purpose of the present study was to examine the acute effects of a thermogenic nutritional supplement containing caffeine, capsaicin, bioperine, and niacin on muscular strength and endurance performance.
Twenty recreationally-active men (mean +/- SD age = 21.5 +/- 1.4 years; stature = 178.2 +/- 6.3 cm; mass = 76.5 +/- 9.9 kg; VO2 PEAK = 3.05 +/- 0.59 L/min-1) volunteered to participate in this randomized, double-blinded, placebo-controlled, cross-over study. All testing took place over a three-week period, with each of the 3 laboratory visits separated by 7 days (+/- 2 hours). During the initial visit, a graded exercise test was performed on a Lode Corival cycle ergometer (Lode, Groningen, Netherlands) until exhaustion (increase of 25 W every 2 min) to determine the maximum power output (W) at the VO2 PEAK (Parvo Medics TrueOne(R) 2400 Metabolic Measurement System, Sandy, Utah). In addition, one-repetition maximum (1-RM) strength was assessed using the bench press (BP) and leg press (LP) exercises. During visits 2 and 3, the subjects were asked to consume a capsule containing either the active supplement (200 mg caffeine, 33.34 mg capsaicin, 5 mg bioperine, and 20 mg niacin) or the placebo (175 mg of calcium carbonate, 160 mg of microcrystalline cellulose, 5 mg of stearic acid, and 5 mg of magnesium stearate in an identical capsule) 30 min prior to the testing. Testing included a time-to-exhaustion (TTE) ride on a cycle ergometer at 80% of the previously-determined power output at VO2 PEAK followed by 1-RM LP and BP tests.
There were no differences (p > 0.05) between the active and placebo trials for BP, LP, or TTE. However, for the BP and LP scores, the baseline values (visit 1) were less than the values recorded during visits 2 and 3 (p </= 0.05).
Our findings indicated that the active supplement containing caffeine, capsaicin, bioperine, and niacin did not alter muscular strength or cycling endurance when compared to a placebo trial. The lack of increases in BP and LP strength and cycle ergometry endurance elicited by this supplement may have been related to the relatively small dose of caffeine, the high intensity of exercise, the untrained status of the participants, and/or the potential for caffeine and capsaicin to increase carbohydrate oxidation.
Antioxidant supplementation is known to increase human endogenous antioxidant (AOX) capacity providing a means of blunting exercise induced reactive oxygen species (ROS). The purpose of this study was to compare the effects of a single acute dose of an AOX (vs blinded placebo) on muscle contractile performance and hormonal responses to a single bout of lower limb 'hypertrophic' resistance training (RT). Fifteen resistance trained subjects (age 23 +/- 4 years: body mass 86 +/- 6 kg) volunteered to participate in the study. Each subject attended the laboratory on three occasions, firstly to determine three repetition maximum (3-RM) isotonic strength in the back squat and perform a familiarisation of the experimental task. On the second/third visits subjects completed the hypertrophic training session (HTS) which consisted of six sets of 10 repetitions of 70% of a predicted 1 RM load (kg). Four hours prior to the HTS the subjects consumed 2 ml[bullet operator]kg-1 total body mass of either the placebo mixture or AOX supplement in a randomised order. Work completed during the strength training session was completed with equipment that had an integrated linear force transducer (Gymaware system, Kinetic Performance Technology, Canberra, Australia). During the placebo trials concentric mean power significantly (p < 0.05) decreased from sets 1-6. Accumulated power output during the AOX HTS was 6746 +/- 5.9 W which was significantly greater compared to the placebo HTS of 6493 +/- 17.1 W (p < 0.05, ES'r = 0.99). Plasma growth hormone (GH) concentration was significantly less immediately following AOX supplementation (6.65 +/- 1.84 vs 16.08 +/- 2.78 ng[bullet operator]ml-1; p < 0.05, ES'r = 0.89). This study demonstrates ingestion of an AOX cocktail prior to a single bout of resistance training improved muscle contractile performance and modulated the GH response following completion of the resistance exercise. Future studies should explore the mechanisms associated with the performance modification and specific muscle adaptations to AOX supplementation in conjunction with heavy RT.
To determine the acute effects of ingesting a thermogenic drink (Celsius, Delray Beach, FL) (TD) on changes in metabolism and lipolysis.
Healthy college-aged male (23.2 +/- 4.0 y, 177.2 +/- 6.1 cm, 81.7 +/- 11.3 kg, 22.8 +/- 7.3 % fat; n = 30) and female (23.4 +/- 3.1 y, 165.6 +/- 8.7 cm, 62.1 +/- 9.9 kg, 28.3 +/- 7.4 % fat; n = 30) participants were matched according to height and weight to consume 336 ml of the TD or a non-caloric, non-caffeinated placebo (PLA). After a 12 h fast, participants reported for pre-consumption measures of height, weight, heart rate, blood pressure, resting energy expenditure (REE), respiratory exchange ratio (RER), glycerol and free-fatty acid (FFA) concentrations. REE and RER were determined at 60, 120, and 180 min post-consumption. Serum glycerol and FFA concentrations were determined at 30, 60, 120 and 180 min post-consumption.
When compared to PLA, TD significantly increased REE at 60, 120 and 180 min (p < 0.05). FFA concentrations were significantly greater in TD compared to PLA at 30, 60, 120 and 180 min post-consumption (p < 0.05). No between-group differences were found in RER.
Acute TD ingestion significantly increased REE, FFA and glycerol appearance. If sustained, these changes may help to promote weight loss and improve body composition; however, these findings are currently unknown as are the general safety and efficacy of prolonged consumption.
The effect of acute L-alanyl-L-glutamine (AG; Sustamine) ingestion on performance changes and markers of fluid regulation, immune, inflammatory, oxidative stress, and recovery was examined in response to exhaustive endurance exercise, during and in the absence of dehydration.
Ten physically active males (20.8 +/- 0.6 y; 176.8 +/- 7.2 cm; 77.4 +/- 10.5 kg; 12.3 +/- 4.6% body fat) volunteered to participate in this study. During the first visit (T1) subjects reported to the laboratory in a euhydrated state to provide a baseline (BL) blood draw and perform a maximal exercise test. In the four subsequent randomly ordered trials, subjects dehydrated to -2.5% of their baseline body mass. For T2, subjects achieved their goal weight and were not rehydrated. During T3 - T5, subjects reached their goal weight and then rehydrated to 1.5% of their baseline body mass by drinking either water (T3) or two different doses (T4 and T5) of the AG supplement (0.05 g.kg-1 and 0.2 g.kg-1, respectively). Subjects then exercised at a workload that elicited 75% of their VO2 max on a cycle ergometer. During T2 - T5 blood draws occurred once goal body mass was achieved (DHY), immediately prior to the exercise stress (RHY), and immediately following the exercise protocol (IP). Resting 24 hour (24P) blood samples were also obtained. Blood samples were analyzed for glutamine, potassium, sodium, aldosterone, arginine vasopressin (AVP), C-reactive protein (CRP), interleukin-6 (IL-6), malondialdehyde (MDA), testosterone, cortisol, ACTH, growth hormone and creatine kinase. Statistical evaluation of performance, hormonal and biochemical changes was accomplished using a repeated measures analysis of variance.
Glutamine concentrations for T5 were significantly higher at RHY and IP than T2 - T4. When examining performance changes (difference between T2 - T5 and T1), significantly greater times to exhaustion occurred during T4 (130.2 +/- 340.2 sec) and T5 (157.4 +/- 263.1 sec) compared to T2 (455.6 +/- 245.0 sec). Plasma sodium concentrations were greater (p < 0.05) at RHY and IP for T2 than all other trials. Aldosterone concentrations at RHY and IP were significantly lower than that at BL and DHY. AVP was significantly elevated at DHY, RHY and IP compared to BL measures. No significant differences were observed between trials in CRP, IL-6, MDA, or in any of the other hormonal or biochemical measures.
Results demonstrate that AG supplementation provided a significant ergogenic benefit by increasing time to exhaustion during a mild hydration stress. This ergogenic effect was likely mediated by an enhanced fluid and electrolyte uptake.
Optimized body composition provides a competitive advantage in a variety of sports. Weight reduction is common among athletes aiming to improve their strength-to-mass ratio, locomotive efficiency, or aesthetic appearance. Energy restriction is accompanied by changes in circulating hormones, mitochondrial efficiency, and energy expenditure that serve to minimize the energy deficit, attenuate weight loss, and promote weight regain. The current article reviews the metabolic adaptations observed with weight reduction and provides recommendations for successful weight reduction and long term reduced-weight maintenance in athletes.
This study examined whether supplementing the diet with a commercial supplement containing zinc magnesium aspartate (ZMA) during training affects zinc and magnesium status, anabolic and catabolic hormone profiles, and/or training adaptations. Forty-two resistance trained males (27 +/- 9 yrs; 178 +/- 8 cm, 85 +/- 15 kg, 18.6 +/- 6% body fat) were matched according to fat free mass and randomly assigned to ingest in a double blind manner either a dextrose placebo (P) or ZMA 30-60 minutes prior to going to sleep during 8-weeks of standardized resistance-training. Subjects completed testing sessions at 0, 4, and 8 weeks that included body composition assessment as determined by dual energy X-ray absorptiometry, 1-RM and muscular endurance tests on the bench and leg press, a Wingate anaerobic power test, and blood analysis to assess anabolic/catabolic status as well as markers of health. Data were analyzed using repeated measures ANOVA. Results indicated that ZMA supplementation non-significantly increased serum zinc levels by 11 - 17% (p = 0.12). However, no significant differences were observed between groups in anabolic or catabolic hormone status, body composition, 1-RM bench press and leg press, upper or lower body muscular endurance, or cycling anaerobic capacity. Results indicate that ZMA supplementation during training does not appear to enhance training adaptations in resistance trained populations.
Intracellular concentrations of adenosine-5’-triphosphate (ATP) are many times greater than extracellular concentrations (1–10 mM versus 10–100 nM, respectively) and cellular release of ATP is tightly controlled. Transient rises in extracellular ATP and its metabolite adenosine have important signaling roles; and acting through purinergic receptors, can increase blood flow and oxygenation of tissues; and act as neurotransmitters. Increased blood flow not only increases substrate availability but may also aid in recovery through removal of metabolic waste products allowing muscles to accomplish more work with less fatigue. The objective of the present study was to determine if supplemental ATP would improve muscle torque, power, work, or fatigue during repeated bouts of high intensity resistance exercise.
Sixteen participants (8 male and 8 female; ages: 21–34 years) were enrolled in a double-blinded, placebo-controlled study using a crossover design. The participants received either supplemental ATP (400 mg/d divided into 2 daily doses) or placebo for 15 d. After an overnight fast, participants underwent strength and fatigue testing, consisting of 3 sets of 50 maximal knee extensions performed on a Biodex® leg dynamometer.
No differences were detected in high peak torque, power, or total work with ATP supplementation; however, low peak torque in set 2 was significantly improved (p < 0.01). Additionally, in set 3, a trend was detected for less torque fatigue with ATP supplementation (p < 0.10).
Supplementation with 400 mg ATP/d for 15 days tended to reduce muscle fatigue and improved a participant’s ability to maintain a higher force output at the end of an exhaustive exercise bout.
This study was designed to evaluate the effects of hydrolyzed protein supplementation upon skeletal muscle total protein and peroxidation in rats following exhaustive swimming exercise.
Twenty-four rats were randomized to 4 experimental groups (n = 6 per group): control group fed standard diet without exercise (SD), exercise (EX), exercise plus standard diet for 72 hours (EX + SD), and exercise plus standard diet supplemented with hydrolyzed protein (2 g/kg/d) for 72 hours (EX + HP). Immediately following exercise, the EX group was euthanized for collecting plasma and skeletal muscle samples. The EX + SD and EX + HP groups were fed their respective diets for 72 hour still plasma and skeletal muscle collection. Skeletal muscle samples were used to measure levels of total protein (TP), malondialdehyde (MDA), and protein carbonyl (PC). Plasma samples were used to analyze the amino acids spectrum.
Compared with the EX + SD, EX + HP presented the significantly increased TP (P = 0.02) and decreased MDA and PC levels (P = 0.035). MDA was negatively correlated with the methionine levels. Moreover, EX + HP maintained higher levels of plasmaleucine, isoleucine, and methionine than EX + SD, which may be associated with the increased skeletal muscle TP levels observed (P < 0.05).
These results collectively suggest that hydrolyzed protein supplementation can improve skeletal muscle TP and ameliorate peroxidation damage in rats subjected to exhaustive exercise stress, which may be, at least in part, related with the maintenance of plasma leucine, isoleucine, and methionine levels.
Elite adolescent figure skaters must accommodate both the physical demands of competitive training and the accelerated rate of bone growth that is associated with adolescence, in this sport that emphasizes leanness. Although, these athletes apparently have sufficient osteogenic stimuli to mitigate the effects of possible low energy availability on bone health, the extent or magnitude of bone accrual also varies with training effects, which differ among skater disciplines.
We studied differences in total and regional bone mineral density in 36 nationally ranked skaters among 3 skater disciplines: single, pairs, and dancers.
Bone mineral density (BMD) of the total body and its regions was measured by dual energy x-ray absorptiometry (DXA). Values for total body, spine, pelvis and leg were entered into a statistical mixed regression model to identify the effect of skater discipline on bone mineralization while controlling for energy, vitamin D, and calcium intake.
The skaters had a mean body mass index of 19.8 ± 2.1 and % fat mass of 19.2 ± 5.8. After controlling for dietary intakes of energy, calcium, and vitamin D, there was a significant relationship between skater discipline and BMD (p = 0.002), with single skaters having greater BMD in the total body, legs, and pelvis than ice dancers (p < 0.001). Pair skaters had greater pelvic BMD than ice dancers (p = 0.001).
Single and pair skaters have greater BMD than ice dancers. The osteogenic effect of physical training is most apparent in single skaters, particularly in the bone loading sites of the leg and pelvis.
The aim of this study was to investigate the influences of rehydration and food consumption on salivary flow, pH, and buffering capacity during bicycle ergometer exercise in participants.
Ten healthy volunteers exercised on a bicycle ergometer at 80% of their maximal heart rate. These sessions lasted for two periods of 20 min separated by 5-min rest intervals. Volunteers were subjected to one of the following conditions: (1) no water (mineral water) or food consumption, (2) only water for rehydration, (3) water and food consumption, (4) a sports drink only for rehydration, and (5) rehydration with a sports drink and food. Statistical significance was assessed using one-way analysis of variance and Dunnett's test (p < 0.05).
The salivary pH decreased significantly during and after exercise in conditions 4 and 5. The salivary buffering capacity decreased significantly during exercise and/or after the exercise in conditions 1, 3, 4, and 5.
The results showed that salivary pH and buffering capacity decreased greatly depending on the combination of a sports drink and food.
The consumption of beverages containing caffeine and taurine before exercising has been associated with increased physical and psychological performances and has been promoted to support the emotional state and provide vitality to consumers. However, there are contradictory results on these issues, it is not clear the effect of every major compound in relation to the whole effect of the beverages and there is a lack in knowledge about their degree of safety for consumption.
This study used a double-blind, placebo controlled, randomized, crossover design. Fourteen male volunteer soldiers from the Colombian army performed different tests to measure their cardiorespiratory fitness (VO2max and maximum heart rate), time to exhaustion, strength (isometric strength), power (vertical jump), concentration (Grid test) and memory (Digits test) after drinking 250 ml of one of the following beverages: one with 80 mg caffeine, one with 1000 mg taurine, one with 80 mg caffeine plus 1000 mg taurine, a commercial energy drink (Red Bull®) or a placebo drink. Subjects were caffeine-consumers that avoided caffeine during the day of evaluation. All beverages were matched in flavor and other organoleptic properties to the commercial one, were bottled in dark plastic bottles and were administered in identical conditions to the participants. Differences between treatments were assessed using repeated measures and analysis of variance.
The mean ± SD values of VO2max, maximum heart rate, time to exhaustion, right handgrip strength, left handgrip strength, vertical jump, Grid test and Digits test were 61.3 ± 6.2 ml/kg.min, 196 ± 6.8 beats per min, 17 ± 1.2 min, 56.8 ± 6.6 kgf, 53.1 ± 5.9 kgf, 41.1 ± 3.8 cm, 19.9 ± 5.9 observed digits and 10.9 ± 3.1 remembered digits after drinking a placebo drink. Comparisons among the commercial drink, caffeine, taurine, caffeine plus taurine and placebo treatments did not show statistically differences in the results of the performed tests. No adverse effects were reported by the participants.
The consumption of caffeine (80 mg) and taurine (1000 mg) or their combination does not increase the physical and cognitive ability in young adults during exercise.
The first law of thermodynamics dictates that body mass remains constant when caloric intake equals caloric expenditure. It should be noted, however, that different diets lead to different biochemical pathways that are not equivalent when correctly compared through the laws of thermodynamics. It is inappropriate to assume that the only thing that counts in terms of food consumption and energy balance is the intake of dietary calories and weight storage. Well-controlled studies suggest that calorie content may not be as predictive of fat loss as is reduced carbohydrate consumption. Biologically speaking, a calorie is certainly not a calorie. The ideal weight loss diet, if it even exists, remains to be determined, but a high-carbohydrate/low-protein diet may be unsatisfactory for many obese individuals.
The influence of feed restriction and different diet's caloric value on the aerobic and anaerobic capacity is unclear in the literature. Thus, the objectives of this study were to determine the possible influences of two diets with different caloric values and the influence of feed restriction on the aerobic (anaerobic threshold: AT) and anaerobic (time to exhaustion: Tlim) variables measured by a lactate minimum test (LM) in rats.
We used 40 adult Wistar rats. The animals were divided into four groups: ad libitum commercial Purina® diet (3028.0 Kcal/kg) (ALP), restricted commercial Purina® diet (RAP), ad libitum semi-purified AIN-93 diet (3802.7 Kcal/kg) (ALD) and restricted semi-purified AIN-93 diet (RAD). The animals performed LM at the end of the experiment, 48 h before euthanasia. Comparisons between groups were performed by analysis of variance (p < 0,05).
At the end of the experiment, the weights of the rats in the groups with the restricted diets were significantly lower than those in the groups with ad libitum diet intakes. In addition, the ALD group had higher amounts of adipose tissue. With respect to energetic substrates, the groups subjected to diet restriction had significantly higher levels of liver and muscle glycogen. There were no differences between the groups with respect to AT; however, the ALD group had lower lactatemia at the AT intensity and higher Tlim than the other groups.
We conclude that dietary restriction induces changes in energetic substrates and that ad libitum intake of a semi-purified AIN-93 diet results in an increase in adipose tissue, likely reducing the density of the animals in water and favouring their performance during the swimming exercises.
Glutathione is an endogenous redox couple in animal cells and plays important roles in antioxidant defense and detoxification, although it is unknown if oral glutathione supplementation affects exercise-induced physiological changes. The present study investigated the effect of glutathione intake on exercise-induced muscle metabolism and fatigue in mice and humans.
ICR mice were divided into 4 groups: sedentary control, sedentary supplemented with glutathione (2.0%, 5 μL/g body weight), exercise control, and exercise supplemented with glutathione. After 2 weeks, the exercise groups ran on a treadmill at 25 m/min for 30 min. Immediately post-exercise, intermuscular pH was measured, and hind limb muscle and blood samples were collected to measure biochemical parameters. In a double-blind, cross-over study, 8 healthy men (35.9 ± 2.0 y) were administered either glutathione (1 g/d) or placebo for 2 weeks. Then, they exercised on a cycle ergometer at 40% maximal heart rate for 60 min. Psychological state and blood biochemical parameters were examined after exercise.
In the mouse experiment, post-exercise plasma non-esterified fatty acids were significantly lower in the exercise supplemented with glutathione group (820 ± 44 mEq/L) compared with the exercise control group (1152 ± 61 mEq/L). Intermuscular pH decreased with exercise (7.17 ± 0.01); however, this reduction was prevented by glutathione supplementation (7.23 ± 0.02). The peroxisome proliferator-activated receptor-γ coactivator-1α protein and mitochondrial DNA levels were significantly higher in the sedentary supplemented with glutathione group compared with the sedentary control group (25% and 53% higher, respectively). In the human study, the elevation of blood lactate was suppressed by glutathione intake (placebo, 3.4 ± 1.1 mM; glutathione, 2.9 ± 0.6 mM). Fatigue-related psychological factors were significantly decreased in the glutathione trial compared with the placebo trial.
These results suggest that glutathione supplementation improved lipid metabolism and acidification in skeletal muscles during exercise, leading to less muscle fatigue.
Pre-exercise sports drinks (PRX) are commonly used as ergogenic aids in athletic competitions requiring aerobic power. However, in most cases, claims regarding their effectiveness have not been substantiated. In addition, the ingredients in PRX products must be deemed acceptable by the athletic governing bodies that regulate their use in training and competition. The purpose of this study was to examine the effects of a modified PRX formulation (known as EM.PACT) from earlier investigations on factors related to maximal aerobic performance during a graded exercise test. The modification consisted of removing creatine to meet the compliance standards set forth by various athletic organizations that regulate the use of nutritional supplements.
Twenty-nine male and female college students varying in levels of aerobic fitness participated in a randomized crossover administration of PRX (containing 14 g/serving of fructose, medium-chain triglycerides, and amino acids mixed with 8 oz. of water) and placebo (PL) 30 minutes prior to performing a treadmill test with approximately one week separation between the trials. VO2max, maximal heart rate (HR), time to exhaustion (Time), and percentage estimated non-protein fat substrate utilization (FA) during two a priori submaximal stages of a graded exercise testing were evaluated.
The VO2max mean value of the PRX trial was significantly greater than the PL trial (P < 0.01). The mean value for Time was also observed to be greater for the PRX trial compared to PL (P < 0.05). Additionally, percentage of FA during submaximal stages of the exercise test was greater for PRX trial in comparison to PL (P < 0.01).
The modified PRX formulation utilized in this investigation supports the findings of the previous investigation and its efficacy for enhancing indices of aerobic performance (specifically VO2max, Time, & FA) during graded exercise testing.
It has been hypothesized that performing aerobic exercise after an overnight fast accelerates the loss of body fat. The purpose of this study was to investigate changes in fat mass and fat-free mass following four weeks of volume-equated fasted versus fed aerobic exercise in young women adhering to a hypocaloric diet. Twenty healthy young female volunteers were randomly assigned to 1 of 2 experimental groups: a fasted training (FASTED) group that performed exercise after an overnight fast (n = 10) or a post-prandial training (FED) group that consumed a meal prior to exercise (n = 10). Training consisted of 1 hour of steady-state aerobic exercise performed 3 days per week. Subjects were provided with customized dietary plans designed to induce a caloric deficit. Nutritional counseling was provided throughout the study period to help ensure dietary adherence and self-reported food intake was monitored on a regular basis. A meal replacement shake was provided either immediately prior to exercise for the FED group or immediately following exercise for the FASTED group, with this nutritional provision carried out under the supervision of a research assistant. Both groups showed a significant loss of weight (P = 0.0005) and fat mass (P = 0.02) from baseline, but no significant between-group differences were noted in any outcome measure. These findings indicate that body composition changes associated with aerobic exercise in conjunction with a hypocaloric diet are similar regardless whether or not an individual is fasted prior to training.
We aimed to investigate the effects of creatine (Cr) supplementation on the plasma lipid profile in sedentary male subjects undergoing aerobic training.
Subjects (n = 22) were randomly divided into two groups and were allocated to receive treatment with either creatine monohydrate (CR) (~20 g.day-1 for one week followed by ~10 g.day-1 for a further eleven weeks) or placebo (PL) (dextrose) in a double blind fashion. All subjects undertook moderate intensity aerobic training during three 40-minute sessions per week, over 3 months. High-density lipoprotein cholesterol (HDL), low-density lipoprotein cholesterol (LDL), very low-density lipoprotein cholesterol (VLDL), total cholesterol (TC), triglyceride (TAG), fasting insulin and fasting glycemia were analyzed in plasma. Thereafter, the homeostasis model assessment (HOMA) was calculated. Tests were performed at baseline (Pre) and after four (Post 4), eight (Post 8) and twelve (Post 12) weeks.
We observed main time effects in both groups for HDL (Post 4 versus Post 8; P = 0.01), TAG and VLDL (Pre versus Post 4 and Post 8; P = 0.02 and P = 0.01, respectively). However, no between group differences were noted in HDL, LDL, CT, VLDL and TAG. Additionally, fasting insulin, fasting glycemia and HOMA did not change significantly.
These findings suggest that Cr supplementation does not exert any additional effect on the improvement in the plasma lipid profile than aerobic training alone.
The measurement of gas exchange has played an invaluable role in metabolic interpretation. The uptake of 1 liter of oxygen is often converted into an energy expenditure estimate of 21.1 kilojoules (e. g., 1 L O-2 = 21.1 kJ or similar to 5 kcal). This article demonstrates both the importance of such a conversion and the potential for misinterpretation. Oxygen uptake during heavy and severe exercise will also be discussed. Journal of the International Society of Sports Nutrition. 2(2): 32-37, 2005
Despite the increasing use of very low carbohydrate ketogenic diets (VLCKD) in weight control and management of the metabolic syndrome there is a paucity of research about effects of VLCKD on sport performance. Ketogenic diets may be useful in sports that include weight class divisions and the aim of our study was to investigate the influence of VLCKD on explosive strength performance.
8 athletes, elite artistic gymnasts (age 20.9 ± 5.5 yrs) were recruited. We analyzed body composition and various performance aspects (hanging straight leg raise, ground push up, parallel bar dips, pull up, squat jump, countermovement jump, 30 sec continuous jumps) before and after 30 days of a modified ketogenic diet. The diet was based on green vegetables, olive oil, fish and meat plus dishes composed of high quality protein and virtually zero carbohydrates, but which mimicked their taste, with the addition of some herbal extracts. During the VLCKD the athletes performed the normal training program. After three months the same protocol, tests were performed before and after 30 days of the athletes' usual diet (a typically western diet, WD). A one-way Anova for repeated measurements was used.
No significant differences were detected between VLCKD and WD in all strength tests. Significant differences were found in body weight and body composition: after VLCKD there was a decrease in body weight (from 69.6 ± 7.3 Kg to 68.0 ± 7.5 Kg) and fat mass (from 5.3 ± 1.3 Kg to 3.4 ± 0.8 Kg p < 0.001) with a non-significant increase in muscle mass.
Despite concerns of coaches and doctors about the possible detrimental effects of low carbohydrate diets on athletic performance and the well known importance of carbohydrates there are no data about VLCKD and strength performance. The undeniable and sudden effect of VLCKD on fat loss may be useful for those athletes who compete in sports based on weight class. We have demonstrated that using VLCKD for a relatively short time period (i.e. 30 days) can decrease body weight and body fat without negative effects on strength performance in high level athletes.
To examine the effects of higher-protein diets on endogenous glucose metabolism in healthy, physically active adults, glucose turnover was assessed in five endurance-trained men (age 21.3 ± 0.3 y, VO2peak 70.6 ± 0.1 mL kg-1 min-1) who consumed dietary protein intakes spanning the current dietary reference intakes.
Using a randomized, crossover design, volunteers consumed 4 week eucaloric diets providing either a low (0.8 g kg-1 d-1; LP), moderate (1.8 g kg-1 d-1; MP), or high (3.6 g kg-1 d-1; HP) level of dietary protein. Glucose turnover (Ra, glucose rate of appearance; and Rd glucose rate of disappearance) was assessed under fasted, resting conditions using primed, constant infusions of [6,6-2H2] glucose. Glucose Ra and Rd (mg kg-1 min-1) were higher for MP (2.8 ± 0.1 and 2.7 ± 0.1) compared to HP (2.4 ± 0.1 and 2.3 ± 0.2, P < 0.05) and LP (2.3 ± 0.1 and 2.2 ± 0.1, P < 0.01) diets. Glucose levels (mmol/L) were not different (P > 0.05) between LP (4.6 ± 0.1), MP (4.8 ± 0.1), and HP (4.7 ± 0.1) diets.
Level of protein consumption influenced resting glucose turnover in endurance athletes in a state of energy balance with a higher rate of turnover noted for a protein intake of 1.8 g kg-1 d-1. Findings suggest that consumption of protein in excess of the recommended dietary allowance but within the current acceptable macronutrient distribution range may contribute to the regulation of blood glucose when carbohydrate intake is reduced by serving as a gluconeogenic substrate in endurance-trained men.
Abstract Background Probiotics are an upcoming group of nutraceuticals claiming positive effects on athlete’s gut health, redox biology and immunity but there is lack of evidence to support these statements. Methods We conducted a randomized, double-blinded, placebo controlled trial to observe effects of probiotic supplementation on markers of intestinal barrier, oxidation and inflammation, at rest and after intense exercise. 23 trained men received multi-species probiotics (1010 CFU/day, Ecologic®Performance or OMNi-BiOTiC®POWER, n = 11) or placebo (n = 12) for 14 weeks and performed an intense cycle ergometry over 90 minutes at baseline and after 14 weeks. Zonulin and α1-antitrypsin were measured from feces to estimate gut leakage at baseline and at the end of treatment. Venous blood was collected at baseline and after 14 weeks, before and immediately post exercise, to determine carbonyl proteins (CP), malondialdehyde (MDA), total oxidation status of lipids (TOS), tumor necrosis factor-alpha (TNF-α), and interleukin-6 (IL-6). Statistical analysis used multifactorial analysis of variance (ANOVA). Level of significance was set at p
This study examined the effects of a whey protein supplement in conjunction with an acute bout of lower body resistance exercise, in recreationally-active males, on serum insulin and insulin like growth factor 1 (IGF-1) and Akt/mTOR signaling markers indicative of muscle protein synthesis: insulin receptor substrate 1 (IRS-1), AKT, mammalian target of rapamycin (mTOR), p70S6 kinase (p70S6K) and 4E-binding protein 1 (4E-BP1).
In a randomized, double-blind, cross-over design, 10 males ingested 1 week apart, either 10 g of whey protein (5.25 g EAAs) or carbohydrate (maltodextrose), 30 min prior to a lower-body resistance exercise bout. The resistance exercise bout consisted of 4 sets of 8-10 reps at 80% of the one repetition maximum (RM) on the angled leg press and knee extension exercises. Blood and muscle samples were obtained prior to, and 30 min following supplement ingestion and 15 min and 120 min post-exercise. Serum and muscle data were analyzed using two-way ANOVA.
No significant differences were observed for IGF-1 (p > 0.05). A significant main effect for Test was observed for serum insulin (p < 0.01) at 30 min post-ingestion and 15 and 120 min post-exercise, with no Supplement × Test interaction (p > 0.05). For the Akt/MTOR signaling intermediates, no significant Supplement × Test interactions were observed (p > 0.05). However, significant main effects for Test were observed for phosphorylated concentrations of IRS, mTOR, and p70S6K, as all were elevated at 15 min post-exercise (p < 0.05). Additionally, a significant main effect for Test was noted for 4E-BP1 (p < 0.05), as it was decreased at 15 min post-exercise.
Ingestion of 10 g of whey protein prior to an acute bout of lower body resistance exercise had no significant preferential effect compared to carbohydrate on systemic and cellular signaling markers indicative of muscle protein synthesis in untrained individuals.
This study examined the effect of simultaneous supplementation of extracellular buffer sodium bicarbonate (SB) and intracellular buffer beta-alanine (BA) on maximal sprint swimming.
Thirteen competitive male swimmers completed 4 different treatments (placebo [PL], SB, BA + PL, and BA + SB) in a crossover procedure. PL or SB supplementation (0.3 g/kg body weight) was ingested 60 min before two maximal 100-m freestyle swims that were performed with a passive recovery of 12-min between each swim. Because of the known long washout period for carnosine, four weeks of BA supplementation (4.8 g per day) was started after the first week of PL or SB supplementation and performance testing.
The first maximal swims were similar, but the increase in time of the second versus the first 100-m swimming time was 1.5 s more (p < 0.05) in PL than in SB. Blood pH values were significantly (p < 0.05) greater in the SB and in the BA + SB groups compared to the PL and BA + PL values. There were no differences in peak blood lactate between the treatments.
Supplementing with SB prior to performing maximal sprint swimming with repetitions under 60 s improves performance. However, co-supplementation with SB and BA did not confer any added benefit on maximal swim performance.
β-alanine supplementation has been shown to improve high-intensity exercise performance and capacity. However, the effects on intermittent exercise are less clear, with no effect shown on repeated sprint activity. The aim of this study was to investigate the effects of β-alanine supplementation on YoYo Intermittent Recovery Test Level 2 (YoYo IR2) performance.
Seventeen amateur footballers were allocated to either a placebo (PLA; N = 8) or β-alanine (BA; N = 9) supplementation group, and performed the YoYo IR2 on two separate occasions, pre and post 12 weeks of supplementation during a competitive season. Specifically, players were supplemented from early to mid-season (PLA: N = 5; BA: N = 6) or mid- to the end of the season (PLA: N = 3; BA: N = 3). Data were analysed using a two factor ANOVA with Tukey post-hoc analyses.
Pre supplementation scores were 1185 ± 216 and 1093 ± 148 m for PLA and BA, with no differences between groups (P = 0.41). YoYo performance was significantly improved for BA (+34.3%, P ≤ 0.001) but not PLA (-7.3%, P = 0.24) following supplementation. 2 of 8 (Early - Mid: 2 of 5; Mid - End: 0 of 3) players improved their YoYo scores in PLA (Range: -37.5 to + 14.7%) and 8 of 9 (Early - Mid: 6 of 6; Mid - End: 2 of 3) improved for BA (Range: +0.0 to +72.7%).
12 weeks of β-alanine supplementation improved YoYo IR2 performance, likely due to an increased muscle buffering capacity resulting in an attenuation of the reduction in intracellular pH during high-intensity intermittent exercise.
The purpose of this study was to examine the efficacy of L-alanyl-L-glutamine (AG) ingestion on basketball performance, including jump power, reaction time, shooting accuracy and fatigue.
Ten women (21.2 ± 1.6 years; height: 177.8 ± 8.7 cm; body mass: 73.5 ± 8.0 kg), all scholarship NCAA Division I basketball players, volunteered for this study. Subjects participated in four trials, each consisting of a 40-min basketball game with controlled time-outs for rehydration. During the first trial (DHY) subjects were not allowed to rehydrate, and the total weight lost during the contest was used to determine fluid replenishment during the subsequent three trials. During one trial subjects consumed only water (W), while during the other two trials subjects consumed the AG supplement mixed in water using either a low dose (1 g per 500 ml) (AG1) or high dose (2 g per 500 ml) (AG2) concentration. All data assessed prior to and following each game were converted into a Δ score (Post results - Pre results). All performance data were then analyzed using a one-way repeated measures analysis of variance.
During DHY subjects lost 1.72 ± 0.42 kg (2.3%) of their body mass. No differences in fluid intake (1.55 ± 0.43 L) were seen between rehydration trials. A 12.5% (p = 0.016) difference in basketball shooting performance was noted between DHY and AG1 and an 11.1% (p = 0.029) difference was seen between AG1 and W. Visual reaction time was significantly greater following AG1 (p = 0.014) compared to DHY. Differences (p = 0.045) in fatigue, as determined by player loads, were seen only between AG2 and DHY. No differences were seen in peak or mean vertical jump power during any trial.
Rehydration with AG appears to maintain basketball skill performance and visual reaction time to a greater extent than water only.
Alfa-Hydroxy-isocaproic acid (HICA) is an end product of leucine metabolism in human tissues such as muscle and connective tissue. According to the clinical and experimental studies, HICA can be considered as an anti-catabolic substance. The present study investigated the effects of HICA supplementation on body composition, delayed onset of muscle soreness (DOMS) and physical performance of athletes during a training period.
Fifteen healthy male soccer players (age 22.1+/-3.9 yr) volunteered for the 4-week double-blind study during an intensive training period. The subjects in the group HICA (n = 8) received 583 mg of sodium salt of HICA (corresponding 500 mg of HICA) mixed with liquid three times a day for 4 weeks, and those in the group PLACEBO (n = 7) received 650 mg of maltodextrin mixed with liquid three times a day for the same period. According to a weekly training schedule, they practiced soccer 3 - 4 times a week, had strength training 1 - 2 times a week, and had one soccer game during the study. The subjects were required to keep diaries on training, nutrition, and symptoms of DOMS. Body composition was evaluated with a dual-energy X-ray absorptiometry (DXA) before and after the 4-week period. Muscle strength and running velocity were measured with field tests.
As compared to placebo, the HICA supplementation increased significantly body weight (p < 0.005) and whole lean body mass (p < 0.05) while fat mass remained constant. The lean body mass of lower extremities increased by 400 g in HICA but decreased by 150 g in PLACEBO during the study. This difference between the groups was significant (p < 0.01). The HICA supplementation decreased the whole body DOMS symptoms in the 4(th )week of the treatment (p < 0.05) when compared to placebo. Muscle strength and running velocity did not differ between the groups.
Already a 4-week HICA supplementation of 1.5 g a day leads to small increases in muscle mass during an intensive training period in soccer athletes.
It has been shown that supplementation with creatine (Cr) and glycerol (Gly), when combined with glucose (Glu) necessary for the enhancement of Cr uptake by skeletal muscle, induces significant improvements in thermoregulatory and cardiovascular responses during exercise in the heat.
To determine whether Cr/Gly-induced thermoregulatory and cardiovascular responses are maintained when the majority (~75%) of the Glu in the Cr/Gly supplement is replaced with the insulintropic agent alpha lipoic acid (Ala).
22 healthy endurance trained cyclists were randomly assigned to receive either 20 g/day (4 × 5 g/day) of Cr, 2 g .kg-1 BM per day (4 × 0.5 g .kg-1 BM per day) of Gly and 150 g/day (4 × 37.5 g/day) of Glu or 20 g/day (4 × 5 g/day) of Cr monohydrate, 2 g .kg-1 BM per day (4 × 0.5 g .kg-1 BM per day) of Gly (100 g/day (4 × 25 g/day) of Glu and 1000 mg/day (4 × 250 mg/day) of Ala for 7 days for 7 days. Exercise trials were conducted pre- and post-supplementation and involved 40 min of constant-load cycling exercise at 70% O2 max by a self-paced 16.1 km time trial at 30°C and 70% relative humidity.
Median and range values of TBW increased significantly by 2.1 (1.3-3.3) L and 1.8 (0.2-4.6) L in Cr/Gly/Glu and Cr/Gly/Glu/Ala groups respectively (P = 0.03) and of BM not significantly by 1.8 (0.2-3.0) kg and 1.2 (0.5-2.1) kg in Cr/Gly/Glu and in Cr/Gly/Glu/Ala, respectively (P = 0.75). During constant load exercise, heart rate (HR) and core temperature (Tcore) were significantly lower post-supplementation: HR was reduced on average by 3.3 ± 2.1 beats/min and by 4.8 ± 3.3 beats/min (mean ± SD) and Tcore by 0.2 ± 0.1 (mean ± SD) in the Cr/Gly/Glu and Cr/Gly/Glu/Ala, respectively The reduction in HR and Tcore was not significantly different between the supplementation groups.
In comparison to the established hyper hydrating Cr/Gly/Glu supplement, supplement containing Cr/Gly/Ala and decreased amount of Glu provides equal improvements in thermoregulatory and cardiovascular responses during exercise in the heat.
Phyllanthus amarus (PA) is a herbal plant containing antioxidant compounds that scavenge free radicals. The reduced oxidative stress may decrease muscle damage leading to early recovery from muscle soreness. This study aimed to evaluate the effects of PA powder on oxidative stress, muscle damage, leukocyte counts, inflammation, and muscle soreness after a single bout of high-intensity exercise.
Twelve men participated in two 3-day phases separated by a 1-week washout in a randomized double-blinded, crossover design. On day 1, randomly divided participants ingested two capsules of either PA (PA group) or placebo (PLA group) 20 min before a single bout of cycling at high intensity for 20 min followed by four capsules (two capsules after lunch and dinner), and six capsules/day for the next 2 days. Blood samples were collected before, immediately after, and 24 and 48 h after the exercise. Pain threshold was measured at the mid-thigh on both legs.
Malondialdehyde concentration in the PA group was lower than that in the PLA group (p < 0.05) 48 h after high-intensity exercise. Vitamin C concentration was greater in the PA than in the PLA group (p < 0.05) immediately after high-intensity exercise. Pain threshold in both legs in the PA group was higher than in the PLA group 24 and 48 h after high-intensity exercise. There were no significant differences in creatine kinase, leukocyte counts or inflammation between groups.
Acute PA supplementation reduced oxidative stress and muscle soreness induced by high-intensity exercise.
Following DIY (do it yourself) diets as well as consuming supplements exceeding by far the recommended daily intake levels, is common among athletes; these dietary habits often lead to an overconsumption of some macro and/or micronutrients, exposing athletes to potential health risks. The aim of this study is to document the development of possible adverse effects in a 33 year-old amateur bodybuilder who consumed for 16 years a DIY high protein diet associated to nutrient supplementation. Body composition, biochemical measures and anamnestic findings were evaluated. We present this case to put on alert about the possible risks of such behavior repeated over time, focusing on the adverse gastrointestinal effects. We discuss the energy and nutrient composition of his DIY diet as well as the use of supplements.
This study provides preliminary data of the potential risks of a long-term DIY dietary supplementation and a high protein diet. In this case, permanent abdominal discomfort was evidenced in an amateur body builder with an intake exceeding tolerable upper limit for vitamin A, selenium and zinc, according to our national and updated recommendations. As many amateur athletes usually adopt self-made diets and supplementation, it would be advisable for them to be supervised in order to prevent health risks due to a long-term DIY diet and over-supplementation.