Acute Effect of Oral N-Acetylcysteine on Muscle Soreness and Exercise Performance in Semi-Elite Rugby Players.

N-acetylcysteine (NAC) supplementation may enhance performance and reduce soreness from acute, repeated-sprint, high-intensity exercise. Our aim was to investigate whether semi-elite rugby union athletes may benefit. In a randomized block design, 17 semi-elite male rugby players were assigned to receive either 1 g oral NAC (n = 8) or placebo (n = 9) for six days. The mean percentage effect of NAC on exercise performance was assessed through completion of a broken bronco exercise test on days 5 and 6 of supplementation. Players self-reported muscle soreness and tolerability to supplements using a modified Muscle Pain and Treatment Satisfaction Questionnaire throughout the supplement duration. NAC produced a likely beneficial performance effect on maximum shuttle sprint time (2.4%; 90% confidence limit ± 4.8%) but was unclear on total time during back-to-back broken bronco tests compared to placebo. NAC had a likely protective effect on subjective muscle soreness during days 1-4 of supplementation (-19% ± 27%) but a very likely harmful effect on days 5 and 6 of supplementation (71% ± 59%). Daily supplementation with 1 g of oral NAC for six days produced no adverse side effects, reduced muscle soreness after one bout of damaging exercise, but increased soreness following the second bout. The performance effects were generally unclear apart from maximal sprint time.

Adding omega-3 fatty acids to a protein-based supplement during pre-season training results in reduced muscle soreness and the better maintenance of explosive power in professional Rugby Union players.

Evidence suggests that omega-3 fatty acid supplementation could reduce muscle soreness and maintain muscle function following eccentric exercise-induced muscle damage. The aim of this applied field study was to investigate the effectiveness of consuming a protein-based supplement containing 1546 mg of omega-3 polyunsaturated fatty acid (PUFA) (551 mg eicosapentaenoic acid (EPA) and 551 mg docosahexaenoic acid (DHA)) twice daily (FO) compared to a protein-based placebo (P) on muscle soreness, countermovement jump (CMJ) performance and psychological well-being in 20 professional Rugby Union players during 5 weeks of pre-season training. Players completed a 5-point-Likert soreness scale with 5 indicating "no soreness" and a questionnaire assessing fatigue, sleep, stress and mood each morning of training, plus they performed CMJ tests once or twice per week. Data were analysed using magnitude-based inferential statistics and are presented as percent beneficial/trivial/harmful. On day 35, there was a likely (% beneficial/trivial/harmful: 94/5/1) moderate (0.75, standardized mean difference (SMD)) beneficial effect of FO vs. P on the change in lower body muscle soreness compared with day 0 (FO: -3.8 ± 21.7%; P: -19.4 ± 11.2%). There was a likely (92/7/0) moderate (SMD: 0.60) beneficial effect of FO vs. P on CMJ performance (change from baseline to day 35, FO: +4.6 ± 5.9%; P: -3.4 ± 8.6%). From day 20, a moderate beneficial effect of FO on fatigue was observed. In terms of practical relevance, the moderate beneficial effect of adding fish oil to a protein-based supplement on muscle soreness translated into the better maintenance of explosive power in elite Rugby Union players during pre-season training.

Probiotic supplementation reduces the duration and incidence of infections but not severity in elite rugby union players.

OBJECTIVES: The attenuation of the number and severity of infections is of importance to athletes. Probiotics use has increased over recent years with beneficial effects believed to include improvements in immune function. Research has focused on their effectiveness for reducing the number, duration and severity of infections amongst endurance athletes. At present no research has been undertaken with team sport athletes. This randomised controlled trial aimed to determine the effectiveness of probiotics on the number, duration and severity of infections amongst elite union rugby players. DESIGN: Randomised control trial with two arms; placebo and probiotic. METHODS: Thirty elite rugby union players were allocated in random order to receive a probiotics supplement or a placebo for four weeks each. Supplements were consumed on a daily basis. There was a four week washout period between treatments. Participants completed a daily diary to identify and rate the severity of any infectious symptoms. RESULTS: During the probiotic treatment 14/30 participants never experienced a single upper respiratory tract illness (URTI) or gastrointestinal (GI) episode, compared to 6/30 on the placebo supplementation (p=0.033). The mean±standard deviation for the number of days of illness tended to be higher for the placebo, (5.8±6.6 days) than probiotic (3.4±4.6 days), (p=0.054). There was no significant difference in the severity of the symptoms between the two treatment groups (p=0.110). CONCLUSIONS: These positive effects of probiotic supplements provide evidence for the beneficial effects of daily supplementation with these probiotic strains in highly trained rugby union players.