Weekly Vitamin D3 supplementation improves aerobic performance in combat sport athletes.

AbstractVitamin D3 supplementation can affect the strength and power of an athlete, however the effect on endurance performance remains unclear. Twenty-seven recreational male combat athletes with at least 12 months experience within combat sports were recruited (age: 24 ± 4 years, stature: 176 ± 6 cm, weight: 77 ± 14 kg). Participants completed baseline testing for blood haemoglobin and haematocrit, upper and lower body VO2peak and upper and lower body Wingate. Following testing participants were stratified to 50,000IU (D1), 80,000IU (D2) or 110,000IU (D3) of vitamin D3 per week. They then completed a 6-week placebo period followed by a 6-week supplementation period. Retesting was carried out after the placebo and supplementation period. There was a significant effect for time for haemoglobin and haematocrit, upper and lower body VO2peak and upper body Wingate power (P < 0.01) but no effect for dose of vitamin D given. Performance data were normalised to vitamin D intake and there was a moderate effect size between D1 and D2 for lower body VO2peak (d = 0.6), upper body VO2peak (d = 0.13) and upper body average power (d = 0.75), with a large effect size between D1 and D2 for haemoglobin (d = 1.19), haematocrit (d = 0.93) and upper body peak power (d = 0.95). There was a large effect size for D1 compared to D3 for all variables (d > 0.8). Therefore, there is no additional benefit to increasing dose above 50,000IU vitamin D per week. Given the endurance adaptations from vitamin D supplementation and the importance of endurance for combat performance, recreational combat athletes should supplement at 50,000IU per week for six weeks.

An overview of the effect of probiotics and exercise on mood and associated health conditions.

The present paper provides a review of the current knowledge relating to the health benefits of probiotics, specially focused on the effects they may have together with physical exercise on mood disorders and related chronic medical conditions.With both these conditions being a substantial contributor to the global disease burden, any alternative therapy must be considered. Probiotics influence the gut microbiota through a complex network of events which can influence mechanisms leading to development of mood disorders such as depression and anxiety. Similarly, through a complex interaction between psychological and neurobiological mechanisms, exercise has been found to play a key role in mood enhancement.

The impact of short duration, high intensity exercise on cardiac troponin release.

The aim of this study was to assess the appearance of cardiac troponins (cTnI and/or cTnT) after a short bout (30 s) of 'all-out' intense exercise and to determine the stability of any exercise-related cTnI release in response to repeated bouts of high intensity exercise separated by 7 days recovery. Eighteen apparently healthy, physically active, male university students completed two all-out 30 s cycle sprint, separated by 7 days. cTnI, blood lactate and catecholamine concentrations were measured before, immediately after and 24 h after each bout. Cycle performance, heart rate and blood pressure responses to exercise were also recorded. Cycle performance was modestly elevated in the second trial [6·5% increase in peak power output (PPO)]; there was no difference in the cardiovascular, lactate or catecholamine response to the two cycle trials. cTnI was not significantly elevated from baseline through recovery (Trial 1: 0·06 ± 0·04 ng ml(-1) , 0·05 ± 0·04 ng ml(-1) , 0·03 ± 0·02 ng ml(-1) ; Trial 2: 0·02 ± 0·04 ng ml(-1) , 0·04 ± 0·03 ng ml(-1) , 0·05 ± 0·06 ng ml(-1) ) in either trial. Very small within subject changes were not significantly correlated between the two trials (r = 0·06; P>0·05). Subsequently, short duration, high intensity exercise does not elicit a clinically relevant response in cTnI and any small alterations likely reflect the underlying biological variability of cTnI measurement within the participants.

Assessment of the upper body contribution to multiple-sprint cycling in men and women.

The aim of this study was to investigate the effect of repeated cycling sprints on power profiles while assessing upper body muscle contraction. Eighteen physically active participants performed 8 × 10 s repeated sprints while muscle activity was recorded via surface electromyography (sEMG) from the brachioradialis (BR), biceps brachii (BB), triceps brachii (TB) and upper trapezius (UT). Measurements were obtained at rest, during a functional maximum contraction (FMC) while participants were positioned in a seated position on the cycle ergometer and during the repeated sprint protocol. Results suggest that mainly type I muscle fibres (MFs) are being recruited within the upper body musculature due to the submaximal and intermittent nature of the contractions. Subsequently, there is no evidence of upper body fatigue across the sprints, which is reflected in the lack of changes in the median frequency of the power spectrum (P<0·05).

The effect of prior upper body exercise on subsequent wingate performance.

It has been reported previously that the upper body musculature is continually active during high intensity cycle ergometry. The aim of this study was to examine the effects of prior upper body exercise on subsequent Wingate (WAnT) performance. Eleven recreationally active males (20.8 ± 2.2 yrs; 77.7 ± 12.0 kg; 1.79 ± 0.04 m) completed two trials in a randomised order. In one trial participants completed 2 × 30 s WAnT tests (WAnT1 and WAnT2) with a 6 min recovery period; in the other trial, this protocol was preceded with 4 sets of biceps curls to induce localised arm fatigue. Prior upper body exercise was found to have a statistically significant detrimental effect on peak power output (PPO) during WAnT1 (P < 0.05) but no effect was observed for mean power output (MPO) (P > 0.05). Handgrip (HG) strength was also found to be significantly lower following the upper body exercise. These results demonstrate that the upper body is meaningfully involved in the generation of leg power during intense cycling.

The Influence of Serial Carbohydrate Mouth Rinsing on Power Output during a Cycle Sprint.

The objective of the study was to investigate the influence of serial administration of a carbohydrate (CHO) mouth rinse on performance, metabolic and perceptual responses during a cycle sprint. Twelve physically active males (mean (± SD) age: 23.1 (3.0) years, height: 1.83 (0.07) m, body mass (BM): 86.3 (13.5) kg) completed the following mouth rinse trials in a randomized, counterbalanced, double-blind fashion; 1. 8 x 5 second rinses with a 25 ml CHO (6% w/v maltodextrin) solution, 2. 8 x 5 second rinses with a 25 ml placebo (PLA) solution. Following mouth rinse administration, participants completed a 30 second sprint on a cycle ergometer against a 0.075 g·kg(-1) BM resistance. Eight participants achieved a greater peak power output (PPO) in the CHO trial, resulting in a significantly greater PPO compared with PLA (13.51 ± 2.19 vs. 13.20 ± 2.14 W·kg(-1), p < 0.05). Magnitude inference analysis reported a likely benefit (81% likelihood) of the CHO mouth rinse on PPO. In the CHO trial, mean power output (MPO) showed a trend for being greater in the first 5 seconds of the sprint and lower for the remainder of the sprint compared with the PLA trial (p > 0.05). No significant between-trials difference was reported for fatigue index, perceived exertion, arousal and nausea levels, or blood lactate and glucose concentrations. Serial administration of a CHO mouth rinse may significantly improve PPO during a cycle sprint. This improvement appears confined to the first 5 seconds of the sprint, and may come at a greater relative cost for the remainder of the sprint. Key pointsThe paper demonstrates that repeated administration of a carbohydrate mouth rinse can significantly improve peak power output during a single 30 second cycle sprint.The ergogenic effect of the carbohydrate mouth rinse may relate to the duration of exposure of the oral cavity to the mouth rinse, and associated greater stimulation of oral carbohydrate receptors.The significant increase in peak power output with the carbohydrate mouth rinse may come at a relative cost for the remainder of the sprint, evidenced by non-significantly lower mean power output and a greater fatigue index in the carbohydrate vs. placebo trial.Serial administration of a carbohydrate mouth rinse may be beneficial for sprint athletes as a method of performance enhancement that minimizes the risk of performance decrement through body mass increase and gastrointestinal disturbances associated with ingesting carbohydrate solutions.