The purpose of this study was to assess the effects of purified oxygenated water on exercise performance under hypoxic conditions. Nine recreational male cyclists (age = 26.6 ± 5.2 y, weight = 87.6 ± 19.5 kg, VO2peak = 46.5 ± 5.9 mL · kg−1 · min−1) completed two 600 kJ cycling time trials under hypoxic conditions (FIO2 = 13.6% O2, Pbar = 641 mmHg) separated by 2 wk. Trials were completed following 3 d ingestion of 35 mL · kg−1 · d−1 of control (CON) or experimental (EXP) water. Time to completion, heart rate (HR), rate of perceived exertion (RPE), pulse oximetry (SaO2), blood gases (PcO2 and PcCO2), and lactate were measured during the trials. Hydration was assessed with pre- and post-exercise body weight and 24-h urine specific gravity. Performance, hydration, and blood oxygenation were unaffected by EXP water. Results of this study suggest that purified oxygenated water does not improve exercise performance in moderately active males.
Stacie L. Wing-Gaia, Andrew W. Subudhi and Eldon W. Askew
Nicola C. Sutton, David J. Childs, Oded Bar-Or and Neil Armstrong
The purpose of this study was to develop a nonmotorized treadmill sprint test (ExNMT) to assess children’s short-term power output, to establish the test’s repeatability, and to compare the results to corresponding Wingate anaerobic test (WAnT) measurements. Nineteen children (aged 10.9±0.3 years) completed 2 ExNMTs and 2 WAnTs. Statistical analysis revealed coefficients of repeatability for the ExNMT that compared very favorably with the WAnT for both peak power (26.6 vs. 44.5 W) and mean power (15.3 vs. 42.1 W). The validity of the ExNMT as a test of anaerobic performance is reflected by significant correlations (p ≤.05) with the WAnT (peak power, r = 0.82; mean power, r = 0.88) and reinforced by the relatively high post-exercise blood lactate concentrations (7.1 ± 1.3 vs. 5.6 ± 1.5 mmol · L−1 for the ExNMT and WAnT, respectively). This study has developed a promising laboratory running test with which to examine young people’s short-term power output.
Patrick Gray, Andrew Chappell, Alison McE Jenkinson, Frank Thies and Stuart R. Gray
Due to the potential anti-inflammatory properties of fish-derived long chain n-3 fatty acids, it has been suggested that athletes should regularly consume fish oils—although evidence in support of this recommendation is not clear. While fish oils can positively modulate immune function, it remains possible that, due to their high number of double bonds, there may be concurrent increases in lipid peroxidation. The current study aims to investigate the effect of fish oil supplementation on exercise-induced markers of oxidative stress and muscle damage. Twenty males underwent a 6-week double-blind randomized placebo-controlled supplementation trial involving two groups (fish oil or placebo). After supplementation, participants undertook 200 repetitions of eccentric knee contractions. Blood samples were taken presupplementation, postsupplementation, immediately, 24, 48, and 72 hr postexercise and muscle soreness/maximal voluntary contraction (MVC) assessed. There were no differences in creatine kinase, protein carbonyls, endogenous DNA damage, muscle soreness or MVC between groups. Plasma thiobarbituric acid reactive substances (TBARS) were lower (p < .05) at 48 and 72 hr post exercise and H2O2 stimulated DNA damage was lower (p < .05) immediately postexercise in the fish oil, compared with the control group. The current study demonstrates that fish oil supplementation reduces selected markers of oxidative stress after a single bout of eccentric exercise.
Charles J. Hardy and W. Jack Rejeski
Three experiments are presented that evaluate the feeling scale (FS) as a measure of affect during exercise. In Experiment 1,.subjects were instructed to check adjectives on the MAACL-R that they would associate with either a "good" or a "bad" feeling during exercise. As predicted, discriminant function analysis indicated that the good/bad dimension of the FS appears to represent a core of emotional expression. In Experiment 2, subjects rated how they felt during exercise at a rate of perceived exertion (RPE) of 11, 15, and 19. There was considerable heterogeneity in FS for each given RPE. Moreover, RPEs and FS ratings were only moderately correlated, r= - .56, suggesting that phenomenologically the two constructs are not isomorphic. Experiment 3 involved three 4-min bouts of exercise at 30, 60, and 90% V02max. Assessed were pre- and post-exercise affect as. .well as RPEs, responses to the FS, Ve, RR, and VO2. Results revealed that RPE and the FS were moderately related, but only at easy and hard workloads. FS ratings evidenced greater variability as metabolic demands increased, and RPEs consistently had stronger ties to physiologic cues than responses to the FS. The theoretical and pragmatic implications of these data are discussed.
Glen Davison and Michael Gleeson
The aim of the present study was to investigate the effect of vitamin C with or without carbohydrate consumed acutely in beverages before and during prolonged cycling on immunoendocrine responses. In a single blind, randomized manner six healthy, moderately trained males exercised for 2.5 h at 60% VO2max and consumed either placebo (PLA), carbohydrate (CHO, 6% w/v), vitamin C (VC, 0.15% w/v) or CHO+VC beverages before and during the bouts; trials were separated by 1 wk. CHO and CHO+VC significantly blunted the post-exercise increase in plasma concentrations of cortisol, ACTH, total leukocyte, and neutrophil counts and limited the decrease in plasma glucose concentration and bacteria-stimulated neutrophil degranulation. VC increased plasma antioxidant capacity (PAC) during exercise (P < 0.05) but had no effect on any of the immunoendocrine responses (P > 0.05). CHO+VC increased PAC compared to CHO but had no greater effects, above those observed with CHO alone, on any of the immunoendocrine responses. In conclusion, acute supplementation with a high dose of VC has little or no effect on the hormonal, interleukin-6, or immune response to prolonged exercise and combined ingestion of VC with CHO provides no additional effects compared with CHO alone.
Daniel G. Syrotuik, Kirsten L. MacFadyen, Vicki J. Harber and Gordon J. Bell
To examine the effects of elk velvet antler supplementation (EVA) combined with training on resting and exercise-stimulated hormonal response, male (n = 25) and female (n = 21) rowers ingested either E VA (560 mg/d) or placebo (PL) during 10 wk of training. VO2max, 2000 m rowing time, leg and bench press strength were determined before and after 5 and 10 wk of training. Serum hormone levels were measured prior to and 5 and 60 min after a simulated 2000 m rowing race. VO2max and strength increased and 2000 m times decreased similarly (P < 0.05) with training. There was no significant difference between the EVA and PL group for any hormonal response. Testosterone (males only) and growth hormone (both genders) were higher 5 min after the simulated race (P < 0.05) but returned to baseline at 60 min. Cortisol was higher 5 and 60 min compared to rest (both genders) (P < 0.05) and was higher 60 min post-exercise following 5 and 10 wk of training. It appears that 10 wk of EVA supplementation does not significantly improve rowing performance nor alter hormonal responses at rest or after acute exercise than training alone.
Lee N. Burkett, Jack Chisum, Jack Pierce, Kent Pomeroy, Jim Fisher and Margie Martin
Twenty spinal-cord-injured subjects (4 quadriplegics and 16 paraplegics) were maximally stress tested on the Arizona State University wheelchair ergometer. Physiological data for each individual were collected as follows: (a) blood flow in the left leg by a photoelectric plethysmograph before exercise, during exercise, and postexercise, and (b) blood lactates before exercise and post-exercise. Eleven subjects had increased leg blood flow and vasodilation during exercise, but vasoconstriction postexercise. The lactate readings, in comparison to able-bodied individuals, were higher at rest but lower at maximal exercise.
Nicolette C. Bishop, Michael Gleeson, Ceri W. Nicholas and Ajmol Ali
Ingesting carbohydrate (CHO) beverages during prolonged, continuous heavy exercise results in smaller changes in the plasma concentrations of several cytokines and attenuates a decline in neutrophil function. In contrast, ingesting CHO during prolonged intermittent exercise appears to have negligible influence on these responses, probably due to the overall moderate intensity of these intermittent exercise protocols. Therefore, we examined the effect of CHO ingestion on plasma interIeukin-6 (IL-6), tumor necrosis factor-α (TNF-α) and lipopolysaccharide (LPS)-stimuIated neutrophil degranulation responses to high-intensity intermittent running. Six trained male soccer players performed 2 exercise trials, 7 days apart, in a randomized, counterbalanced design. On each occasion, they completed six 15-min periods of intermittent running consisting of maximal sprinting interspersed with less intense periods of running and walking. Subjects consumed either CHO or artificially sweetened placebo(PLA) beverages immediately before and at 15-min intervals during the exercise. At 30 min post-exercise, CHO versus PLA was associated with a higher plasma glucose concentration (p< .01), a lower plasma cortisol and IL-6 concentration (p < .02), and fewer numbers of circulating neutrophils (p < .05). Following the exercise, LPS-stimulated elastase release per neutrophil fell 31 % below baseline values on the PLA trial (p = .06) compared with 11% on the CHO trial (p = .30). Plasma TNF-α concentration increased following the exercise (main effect of time, p < .001) but was not affected by CHO. These data indicate that CHO ingestion attenuates changes in plasma IL-6 concentration, neutrophil trafficking, and LPS-stimulated neutrophil degranulation in response to intermittent exercise that involves bouts of very high intensity exercise.
Nidia Rodriguez-Sanchez and Stuart D.R. Galloway
Dual energy x-ray absorptiometry (DXA) is a popular tool to determine body composition (BC) in athletes, and is used for analysis of fat-free soft tissue mass (FFST) or fat mass (FM) gain/loss in response to exercise or nutritional interventions. The aim of the current study was to assess the effect of exercise-heat stress induced hypohydration (HYP, >2% of body mass (BM) loss) vs. maintenance of euhydration (EUH) on DXA estimates of BC, sum of skinfolds (SF), and impedance (IMP) measurements in athletes. Competitive athletes (23 males and 15 females) recorded morning nude BM for 7 days before the first main trial. Measurements on the first trial day were conducted in a EUH condition, and again after exercise-heat stress induced HYP. On the second trial day, fluid and electrolyte losses were replaced during exercise using a sports drink. A reduction in total BM (1.6 ± 0.4 kg; 2.3 ± 0.4% HYP) and total FFST (1.3 ± 0.4 kg), mainly from trunk (1.1 ± 0.5 kg), was observed using DXA when participants were HYP, reflecting the sweat loss. Estimated fat percent increased (0.3 ± 0.3%), however, total FM did not change (0.1 ± 0.2 kg). SF and IMP declined with HYP (losses of 1.5 ± 2.9% and 1.6 ± 3% respectively) suggesting FM loss. When EUH was maintained there were no significant changes in BM, DXA estimates, or SF values pre to post exercise, but IMP still declined. We conclude that use of DXA for FFST assessment in athletes must ensure a EUH state, particularly when considering changes associated with nutritional or exercise interventions.
Matthew S. Ganio, Jennifer F. Klau, Elaine C. Lee, Susan W. Yeargin, Brendon P. McDermott, Maxime Buyckx, Carl M. Maresh and Lawrence E. Armstrong
The purpose of this study was to compare the effects of a carbohydrate-electrolyte plus caffeine, carnitine, taurine, and B vitamins solution (CE+) and a carbohydrate-electrolyte-only solution (CE) vs. a placebo solution (PLA) on cycling performance and maximal voluntary contraction (MVC). In a randomized, double-blind, crossover, repeated-measures design, 14 male cyclists (M ± SD age 27 ± 6 yr, VO2max 60.4 ± 6.8 ml · kg−1 · min−1) cycled for 120 min submaximally (alternating 61% ± 5% and 75% ± 5% VO2max) and then completed a 15-min performance trial (PT). Participants ingested CE+, CE, or PLA before (6 ml/kg) and every 15 min during exercise (3 ml/kg). MVC was measured as a single-leg isometric extension (70° knee flexion) before (pre) and after (post) exercise. Rating of perceived exertion (RPE) was measured throughout. Total work accumulated (KJ) during PT was greater (p < .05) in CE+ (233 ± 34) than PLA (205 ± 52) but not in CE (225 ± 39) vs. PLA. MVC (N) declined (p < .001) from pre to post in PLA (988 ± 213 to 851 ± 191) and CE (970 ± 172 to 870 ± 163) but not in CE+ (953 ± 171 to 904 ± 208). At Minutes 60, 90, 105, and 120 RPE was lower in CE+ (14 ± 2, 14 ± 2, 12 ± 1, 15 ± 2) than in PLA (14 ± 2, 15 ± 2, 14 ± 2, 16 ± 2; p < .001). CE+ resulted in greater total work than PLA. CE+, but not PLA or CE, attenuated pre-to-post MVC declines. Performance increases during CE+ may have been influenced by lower RPE and greater preservation of leg strength during exercise in part as a result of the hypothesized effects of CE+ on the central nervous system and skeletal muscle.