Citrulline Malate Fails to Improve German Volume Training Performance in Healthy Young Men and Women.

Citrulline malate (CM) is purported to buffer lactic acid, enhance oxygen delivery, and attenuate muscle soreness. Anaerobic exercise trials with CM have produced conflicting results. The aim of the current investigation was to test the efficacy of CM on resistance training (RT) with the hypothesis that CM would improve performance. A double-blind, counter-balanced, randomized control trial was utilized to assess the effects of CM on RT. Nineteen participants (8 female) (25.7 ± 7.7 years), regularly engaged in RT, consumed either 8 g of CM (1.1:1 ratio) or a placebo (6 g citric acid). Participants attempted to perform a German Volume Training (GVT) protocol comprising 10 sets of 10 repetitions of barbell curls at 80% of their one repetition maximum. Repeated ANOVA suggested no effect of CM on RT performance (treatment × time × order p = .217). There was no difference (p = .320) in the total number of reps over the 10 sets (CM median = 57, IQR 45-73; placebo median = 61, IQR 51-69). Blood lactate and creatine kinase did not differ between CM and placebo (p > .05). Finally, total muscle soreness was reduced significantly in CM compared to placebo (treatment × time × order p = .004). These results require corroboration; an ergogenic benefit is yet to be established, and weight trainers should exercise caution when assessing the efficacy of CM. Future research should focus on the potential effects of loading doses of CM.

The effects of a sleep/recovery supplement: 'Night Time Recharge' on sleep parameters in young adults.

BACKGROUND: Concentrated cherry juice reportedly contains melatonin which, in turn, has been highlighted as an important regulator in initiating sleep. AIM: The present investigation aims to clarify whether Night Time Recharge (NTR), a marketed sleep aid containing cherry extract, improves key sleep parameters in young, active adults with mildly poor sleep. METHODS: A double-blind, randomized, placebo-controlled, cross-over study design was employed. Twenty participants (nine female) consumed either NTR or a placebo for seven days. Accelerometers were used to assess sleep quality and physical activity levels. Urinary levels of 6-sulphatoxymelatonin (6-SMT), a marker of melatonin synthesis, was assessed via enzyme-linked immunosorbent assay. RESULTS: 6-SMT levels increased following NTR treatment (28.95 ng/ml) compared with placebo (4.0 ng/ml) (p < 0.001). There was also a significant difference (p = 0.047) in dietary tryptophan consumption during the NTR treatment (1236 mg) versus placebo (1149 mg). No trace of melatonin was detected from our analysis of the supplement. NTR had no significant effect on any sleep parameters with the exception of sleep latency (p = 0.001). CONCLUSIONS: As chemical analysis of NTR by liquid-chromatography mass-spectrometry identified no detectable melatonin, the tryptophan content of the supplement is a likely reason for improvement in sleep latency. These results are in contrast to previous studies which have found a positive effect on sleep following cherry supplementation. Future work should focus on sleep latency and investigating whether cherry juice is effective in participants with problems in initiating sleep.

Citrulline malate supplementation does not improve German Volume Training performance or reduce muscle soreness in moderately trained males and females.

BACKGROUND: Use of supplements to aid performance is common practice amongst recreationally active individuals, including those without a sufficient evidence base. This investigation sought to assess whether acute supplementation with 8 g of citrulline malate (CM) (1.11: 1 ratio) would improve anaerobic performance. METHODS: A randomised double blind placebo control trial was employed, using a counterbalanced design. We recruited recreationally active men and women to take part in an isokinetic chair protocol, based on German Volume Training (GVT) whereby participants attempted to perform 10 sets of 10 repetitions against a force representing 70% of their peak concentric force. RESULTS: The number of repetitions achieved over the course of the GVT was 94.0 ± 7.9 and 90.9 ± 13.9 for placebo and CM respectively. There was no significant difference between the placebo and CM treatment for number of repetitions (P = 0.33), isometric (P = 0.60), concentric (P = 0.38), or eccentric (P = 0.65) peak force following the GVT. Total muscle soreness was significantly higher in the CM compared to the placebo treatment following the GVT protocol over 72 h (P = 0.01); although this was not accompanied by a greater workload/number of repetitions in the CM group. CONCLUSIONS: We conclude that an acute dose of CM does not significantly affect anaerobic performance using an isokinetic chair in recreational active participants. Practical implications include precaution in recommending CM supplementation. Coaches and athletes should be aware of the disparity between the chemical analyses of the products reviewed in the present investigation versus the manufacturers' claims.

Effect of bilberry juice on indices of muscle damage and inflammation in runners completing a half-marathon: a randomised, placebo-controlled trial.

BACKGROUND: Emerging evidence indicates that fruits rich in polyphenols may attenuate exercise-induced muscle damage and associated markers of inflammation and soreness. This study was conducted to determine whether bilberry juice (BJ), which is particularly rich in polyphenols, reduces markers of muscle damage in runners completing a half marathon. METHODS: A total of 21 recreationally trained runners (age 30.9 ± 10.4 y; mass 71.6 ± 11.0 kg; M = 16; F = 5) were recruited to a single blind, randomised, placebo-controlled, parallel study. Participants were block randomised to consume 2 × 200 ml of BJ or energy-matched control drink (PLA) for 5 d before the Sheffield Half Marathon, on race day, and for 2 days post-race. Measurements of delayed onset muscle soreness (DOMS), muscle damage (creatine kinase; CK) and inflammation (c-reactive protein; CRP) were taken at baseline, pre-race, post-race, 24 h post-race and 48 h post-race. The effect of treatment on outcome measures was analysed using magnitude-based inferences based on data from 19 participants; 2 participants were excluded from the analyses because they did not provide samples for all time points. RESULTS: The half marathon caused elevations in DOMS, CRP and CK. BJ had a possibly harmful effect on DOMS from pre-race to immediately post-race (11.6%, 90% CI ± 14.7%), a likely harmful effect on CRP from pre-race to 24 h post-race (mean difference ES 0.56, 90% CI ± 0.72) and a possibly harmful effect on CRP from pre-race to 48 h post-race (ES 0.12, 90% CI ± 0.69). At other time points, the differences between the BJ and PLA groups in DOMS and CRP were unclear, possibly trivial or likely trivial. Differences in the changes in CK between BJ and PLA were unclear at every time point other than from baseline to pre-race, where BJ had a possibly harmful effect on reducing muscle damage (ES 0.23, 90% CI ± 0.57). CONCLUSION: Despite being a rich source of antioxidant and anti-inflammatory phytochemicals, BJ evoked small to moderate increases in exercise-induced DOMS and CRP. Further larger studies are required to confirm these unexpected preliminary results.