A pilot study: bovine colostrum supplementation and hormonal and autonomic responses to competitive cycling.

AIM: The aim of this pilot investigation was to examine the influence of bovine colostrum protein concentrate (CPC) supplementation on salivary hormones, salivary IgA and heart rate variability over consecutive days of competitive cycling. METHODS: Ten highly-trained male road cyclists (mean±SEM; age=22.2±4.7 yr; mass=70.5±4.5 kg; VO2max=72.9±3.8 mL.kg-1.min-1) were randomly assigned to a control (N.=6, 10g whey protein concentrate/day) or bovine CPC group (N.=4, 10 g bovine CPC/day). Cyclists provided a baseline saliva sample before commencing eight weeks of supplementation, and competing in a five day cycle race. Cyclists provided saliva samples and measured heart rate variability (HRV) each day of the race. Saliva samples were analysed for cortisol, testosterone and IgA concentrations. RESULTS: Bovine CPC supplementation was associated with increased morning cortisol concentration on the first day of racing when compared to the control group (P=0.004) and significantly prevented a decrease in testosterone concentration over the race period (P≤0.05). Across the race period parasympathetic indices of HRV were elevated in the bovine CPC group and reduced in the control group (P≤0.05), while there were no significant differences in salivary IgA between groups. CONCLUSION: Bovine CPC supplementation maintained salivary testosterone concentration and modulated autonomic activity over consecutive days of competitive cycling. This pilot study provides justification to explore the effects of bovine CPC on recovery in endurance athletes further.

The influence of bovine colostrum supplementation on exercise performance in highly trained cyclists.

PURPOSE: The aim of this experiment was to investigate the influence of low dose bovine colostrum supplementation on exercise performance in cyclists over a 10 week period that included 5 days of high intensity training (HIT). METHODS: Over 7 days of preliminary testing, 29 highly trained male road cyclists completed a VO(2max) test (in which their ventilatory threshold was estimated), a time to fatigue test at 110% of ventilatory threshold, and a 40 km time trial (TT40). Cyclists were then assigned to either a supplement (n = 14, 10 g/day bovine colostrum protein concentrate (CPC)) or a placebo group (n = 15, 10 g/day whey protein) and resumed their normal training. Following 5 weeks of supplementation, the cyclists returned to the laboratory to complete a second series of performance testing (week 7). They then underwent five consecutive days of HIT (week 8) followed by a further series of performance tests (week 9). RESULTS: The influence of bovine CPC on TT40 performance during normal training was unclear (week 7: 1+/-3.1%, week 9: 0.1+/-2.1%; mean+/-90% confidence limits). However, at the end of the HIT period, bovine CPC supplementation, compared to the placebo, elicited a 1.9+/-2.2% improvement from baseline in TT40 performance and a 2.3+/-6.0% increase in time trial intensity (% VO(2max)), and maintained TT40 heart rate (2.5+/-3.7%). In addition, bovine CPC supplementation prevented a decrease in ventilatory threshold following the HIT period (4.6+/-4.6%). CONCLUSION: Low dose bovine CPC supplementation elicited improvements in TT40 performance during an HIT period and maintained ventilatory threshold following five consecutive days of HIT.

Physiological responses to repeated bouts of high-intensity ultraendurance cycling--a field study case report.

The present study aimed to 1) examine the relationship between laboratory-based measures and high-intensity ultraendurance (HIU) performance during an intermittent 24-h relay ultraendurance mountain bike race (approximately 20 min cycling, approximately 60 min recovery), and 2) examine physiological and performance based changes throughout the HIU event. Prior to the HIU event, four highly-trained male cyclists (age = 24.0 +/- 2.1 yr; mass = 75.0 +/- 2.7 kg; VO2peak = 70 +/- 3 ml x kg(-1) x min(-1)) performed 1) a progressive exercise test to determine peak volume of oxygen uptake (VO2peak), peak power output (PPO), and ventilatory threshold (T(vent)), 2) time-to-fatigue tests at 100% (TF100) and 150% of PPO (TF150), and 3) a laboratory simulated 40-km time trial (TT40). Blood lactate (Lac(-)), haematocrit and haemoglobin were measured at 6-h intervals throughout the HIU event, while heart rate (HR) was recorded continuously. Intermittent HIU performance, performance HR, recovery HR, and Lac(-) declined (P < 0.05), while plasma volume expanded (P < 0.05) during the HIU event. TF100 was related to the decline in lap time (r = -0.96; P < 0.05), and a trend (P = 0.081) was found between TF150 and average intermittent HIU speed (r = 0.92). However, other measures (VO2peak, PPO, T(vent), and TT40) were not related to HIU performance. Measures of high-intensity endurance performance (TF100, TF150) were better predictors of intermittent HIU performance than traditional laboratory-based measures of aerobic capacity.

Reproducibility of a laboratory-based 40-km cycle time-trial on a stationary wind-trainer in highly trained cyclists.

The purpose of the present study was to examine the reproducibility of laboratory-based 40-km cycle time-trial performance on a stationary wind-trainer. Each week, for three consecutive weeks, and on different days, forty-three highly trained male cyclists (x +/- SD; age = 25 +/- 6 y; mass = 75 +/- 7 kg; peak oxygen uptake [VO (2)peak] = 64.8 +/- 5.2 ml x kg (-1) x min (-1)) performed: 1) a VO (2)peak test, and 2) a 40-km time-trial on their own racing bicycle mounted to a stationary wind-trainer (Cateye - Cyclosimulator). Data from all tests were compared using a one-way analysis of variance. Performance on the second and third 40-km time-trials were highly related (r = 0.96; p < 0.001), not significantly different (57 : 21 +/- 2 : 57 vs. 57 : 12 +/- 3 : 14 min:s), and displayed a low coefficient of variation (CV) = 0.9 +/- 0.7 %. Although the first 40-km time-trial (58 : 43 +/- 3 : 17 min:s) was not significantly different from the second and third tests (p = 0.06), inclusion of the first test in the assessment of reliability increased within-subject CV to 3.0 +/- 2.9 %. 40-km time-trial speed (km x h (-1)) was significantly (p < 0.001) related to peak power output (W; r = 0.75), VO (2)peak (l x min (-1); r = 0.53), and the second ventilatory turnpoint (l x min (-1); r = 0.68) measured during the progressive exercise tests. These data demonstrate that the assessment of 40-km cycle time-trial performance in well-trained endurance cyclists on a stationary wind-trainer is reproducible, provided the athletes perform a familiarization trial.