Given the common view that pre-exercise nutrition/breakfast is important for performance, the present study investigated whether breakfast influences resistance exercise performance via a physiological or psychological effect. Twenty-two resistance-trained, breakfast-consuming men completed three experimental trials, consuming water-only (WAT), or semi-solid breakfasts containing 0 g/kg (PLA) or 1·5 g/kg (CHO) maltodextrin. PLA and CHO meals contained xanthan gum and low-energy flavouring (approximately 122 kJ), and subjects were told both ‘contained energy’. At 2 h post-meal, subjects completed four sets of back squat and bench press to failure at 90 % ten repetition maximum. Blood samples were taken pre-meal, 45 min and 105 min post-meal to measure serum/plasma glucose, insulin, ghrelin, glucagon-like peptide-1 and peptide tyrosine-tyrosine concentrations. Subjective hunger/fullness was also measured. Total back squat repetitions were greater in CHO (44 (sd 10) repetitions) and PLA (43 (sd 10) repetitions) than WAT (38 (sd 10) repetitions; P < 0·001). Total bench press repetitions were similar between trials (WAT 37 (sd 7) repetitions; CHO 39 (sd 7) repetitions; PLA 38 (sd 7) repetitions; P = 0·130). Performance was similar between CHO and PLA trials. Hunger was suppressed and fullness increased similarly in PLA and CHO, relative to WAT (P < 0·001). During CHO, plasma glucose was elevated at 45 min (P < 0·05), whilst serum insulin was elevated (P < 0·05) and plasma ghrelin suppressed at 45 and 105 min (P < 0·05). These results suggest that breakfast/pre-exercise nutrition enhances resistance exercise performance via a psychological effect, although a potential mediating role of hunger cannot be discounted.

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The disposition of pituitary-derived bovine growth hormone (pbST) and of a recombinant bovine growth hormone (rbST) produced by Lilly (somidobove, USAN) were compared after an intravenous bolus administration (36.69 micrograms/kg for pbST and 35 micrograms/kg for rbST) to eight lactating cows in a crossover study. It was shown that dose-dependent parameters (volume of distribution, clearance) were significantly different between the two test articles. The steady mean state volume of distribution (.10 +/- .018 vs .12 +/- .015 L/kg) and clearance (.119 +/- .012 vs .143 +/- .011 L.kg-1.h-1) were lower for the pbST than for the somidobove. In contrast, the mean (+/- SD) residence times were not different for the two test articles (50.0 +/- 8.6 vs 46.9 +/- 5.9 min for pbST and somidobove, respectively). The origin of the difference is unclear, but it cannot be explained by the slight difference between the administered dose of the two test articles (< 5%) because the actual dose rate was used to calculate all dose-dependent parameters.

Yucca and fenugreek are purported to reduce inflammation and improve metabolic response to exercise. Therefore, we evaluated the effects of a dietary supplement (DigestaWell NRG) in unconditioned horses completing an exercise challenge test. In this study, 10 unfit horses were assigned to receive exercise (EXC; n = 5) or the dietary supplement (SUP; n = 5). Horses assigned to EXC were ridden daily at a walk, trot, and canter. Horses assigned to SUP were ridden once per week at a walk and slow trot, but received no other exercise. Horses underwent a 14-min standardized exercise test (5 min walk, 5 min trot, 4 min canter) prior to (Period1) and after a 4-wk treatment period (Period2). Heart rate, respiration rate, blood lactate concentrations, and thermal images of six muscle groups were obtained prior to, immediately after, and 2 hr post-test. Data were analyzed using repeated measures ANOVA. During Period1, similar (P > 0.05) post-exercise increases in heart rate, respiration rate, blood lactate, and thermal images were observed regardless of treatment group. During Period2, SUP horses had lower (P < 0.001) lactate concentrations than EXC horses at 2 hr post exercise, and it is possible that these lower concentrations are responsible for lower peripheral temperatures. Infrequently exercised horses may benefit from yucca and fenugreek supplementation due to the observed effect of these herbs to reduce post-exercise lactate concentrations and peripheral temperatures.