Critical Power, Work Capacity, and Recovery Characteristics of Team-Pursuit Cyclists.

PURPOSE: Leading a 4-km team pursuit (TP) requires high-intensity efforts above critical power (CP) that deplete riders' finite work capacity (W'), whereas riders following in the aerodynamic draft may experience some recovery due to reduced power demands. This study aimed to determine how rider ability and CP and W' measures impact TP performance and the extent to which W' can reconstitute during recovery positions in a TP race. METHODS: Three TP teams, each consisting of 4 males, completed individual performance tests to determine their CP and W'. Teams were classified based on their performance level as international (INT), national (NAT), or regional (REG). Each team performed a TP on an indoor velodrome (INT: 3:49.9; NAT: 3:56.7; and REG: 4:05.4; min:s). Ergometer-based TP simulations with an open-ended interval to exhaustion were performed to measure individual ability to reconstitute W' at 25 to 100 W below CP. RESULTS: The INT team possessed higher CP (407 [4] W) than both NAT (381 [13] W) and REG (376 [15] W) (P < .05), whereas W' was similar between teams (INT: 27.2 [2.8] kJ; NAT: 29.3 [2.4] kJ; and REG: 28.8 [1.6] kJ; P > .05). The INT team expended 104% (5%) of their initial W' during the TP and possessed faster rates of recovery than NAT and REG at 25 and 50 W below CP (P < .05). CONCLUSIONS: The CP and rate of W' reconstitution have a greater impact on TP performance than W' magnitude and can differentiate TP performance level.

The impact of 100 hours of exercise and sleep deprivation on cognitive function and physical capacities.

In this study, we examined the effect of 96-125 h of competitive exercise on cognitive and physical performance. Cognitive performance was assessed using the Stroop test (n = 9) before, during, and after the 2003 Southern Traverse adventure race. Strength (MVC) and strength endurance (time to failure at 70% current MVC) of the knee extensor and elbow flexor muscles were assessed before and after racing. Changes in vertical jump (n = 24) and 30-s Wingate performance (n = 27) were assessed in a different group of athletes. Complex response times were affected by the race (16% slower), although not significantly so (P = 0.18), and were dependent on exercise intensity (less so at 50% peak power output after racing). Reduction of strength (P < 0.05) of the legs (17%) and arms (11%) was equivalent (P = 0.17). Reductions in strength endurance were inconsistent (legs 18%, P = 0.09; arms 13%, P = 0.40), but were equivalent between limbs (P = 0.80). Similar reductions were observed in jump height (-8 +/- 9%, P < 0.01) and Wingate peak power (-7 +/- 15%, P = 0.04), mean power (-7 +/- 11%, P < 0.01), and end power (-10 +/- 11%, P < 0.01). We concluded that: moderate-intensity exercise may help complex decision making during sustained stress; functional performance was modestly impacted, and the upper and lower limbs were affected similarly despite being used disproportionately.

Effects of prior heavy exercise on energy supply and 4000-m cycling performance.

PURPOSE: This study was designed to determine the effects of prior exercise on energy supply and performance in a laboratory-based 4000-m time trial. METHODS: After one familiarization trial, eight well-trained cyclists (mean +/- SD; age = 30 +/- 8 yr, body mass = 78.7 +/- 8.6 kg, stature = 181 +/- 5 cm, .VO2 peak = 63.7 +/- 6.7 mL.kg.(-1)min(-1), peak power output (PPO) = 366 +/- 39 W) performed three 4000-m laboratory-based cycling time trials each preceded by one of three prior exercise regimens in randomized order: no prior exercise (control), prior heavy exercise, and self-selected prior exercise. RESULTS: Cyclists adopted a wide range of self-selected prior exercise regimens: duration ranged = 11-80 min, intensity = 48-120% PPO, and recovery = 2-11 min. Relative to control, pre-time-trial blood lactate was raised by 2.5 +/- 1.9 and 1.4 +/- 1.5 mmol.L(-1) after prior heavy and self-selected exercise, respectively. The 4000 m was completed 2.0 +/- 2.3% and 2.2 +/- 1.9% faster after prior heavy and self-selected exercise regimens, respectively, and mean power output was 5.4 +/- 3.6% and 6.0 +/- 5.8% higher, respectively. The overall aerobic contribution (.VO2) and oxygen deficit were not different between conditions (approximately 323 +/- 23 and approximately 64 +/- 22 mL.kg,(-1) respectively), although .VO2 was higher (P < 0.05) in the prior heavy (by 2.1-5.8 mL.kg(-1).min(-1)) and self-selected (2.5-4.3 mL.kg(-1).min(-1)) regimens compared with the control throughout the first half of the time trial. CONCLUSION: Very high intensity cycling performance was improved after both self-selected and prior heavy exercise. Such priming increased the early aerobic contribution but did not change overall aerobic contribution or oxygen deficit. Thus, athletes seem to manage their energy potential to exploit the available anaerobic capacity, independent of the aerobic contribution. Athletes are advised to perform a bout of heavy exercise as part of their prior exercise regimen.

Intensity and physiological strain of competitive ultra-endurance exercise in humans.

The aim of this study was to determine the magnitude and pattern of intensity, and physiological strain, of competitive exercise performed across several days, as in adventure racing. Data were obtained from three teams of four athletes (7 males, 5 females; mean age 36 years, s = 11; cycling .VO(2 peak) 53.9 ml . kg(-1) . min(-1), s = 6.3) in an international race (2003 Southern Traverse; 96 - 116 h). Heart rates (HR) averaged 64% (95% confidence interval: +/- 4%) of heart rate range [%HRR = (HR - HR(min))/(HR(max) - HR(min)) x 100] during the first 12 h of racing, fell to 41% (+/-4%) by 24 h, and remained so thereafter. The level and pattern of heart rate were similar across teams, despite one leading and one trailing all other teams. Core temperature remained between 36.0 and 39.2 degrees C despite widely varying thermal stress. Venous samples, obtained before, during, and after the race, revealed increased neutrophil, monocyte and lymphocyte concentrations (P < 0.01), and increased plasma volume (25 +/- 10%; P < 0.01) with a stable sodium concentration. Standardized exercise tests, performed pre and post race, showed little change in the heart rate-work rate relationship (P = 0.53), but a higher perception of effort post race (P < 0.01). These results provide the first comprehensive report of physiological strain associated with adventure racing.