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To examine the effect of a nutritional supplement (ATP-E™) on high intensity exercise performance, 23 physically active males volunteered to perform six Wingate Anaerobic Power tests. Tests were performed prior to and at 14 and 21 days during ATP-E~o~r placebo ingestion. f i e experiment followed a double-blind and random-order design. Twelve subjects (responders, R) showed an increase in preexercise blood ATP on Day 14 of ATP-E™ ingestion compared to control measures. The remaining 11 subjects (nonresponders, NR) had no change in pree~e~cibselo od ATP. Peak power and mean power were unchanged for both R and NR subjects across the exercise tests, but R experienced a decrease (p < 0.05) in immediate postexercise plasma lactate on Day 14 of ATP-E™ testing compared to their control measures. NR had no change in peak plasma lactate at any time during the study. The results suggest that short-term high intensity exercise performance was maintained in R with less reliance on anaerobic metabolism, and that response was evident following 14 days of ATP-E™ ingestion.

The purpose of this investigation was to determine the effect of systematic changes in hip position/configuration on cycling peak anaerobic power (AP) and anaerobic capacity (AC). Fourteen male recreational cyclists (ages 21-32 yrs) were tested in four hip positions (25, 50, 75, and 100°), as defined by the angle formed by the seat tube and a vertical line. Rotating the seat to maintain a backrest perpendicular to the ground induced a systematic decrease in hip angle from the 25 to the 100° position. The Wingate anaerobic cycling test was used on a Monark cycle ergometer with a resistance of 85 gm/kg of the subject’s body mass. Repeated-measures MANOVAs and post hoc tests revealed that AP and AC in the 75° hip position were significantly greater than in the 25 or 100° position and that a second-order function best describes the trend in AP and AC with changes in hip position.

Purpose: To determine aerobic and anaerobic demands of mountain bike cross-country racing. Methods: Twelve elite cyclists (7 males; $\dot{\mathrm{V}}{\mathrm{O}}_2\text{max}$  = 73.8 [2.6] mL·min^-1·kg⁻¹, maximal aerobic power [MAP] = 370 [26] W, 5.7 [0.4] W·kg⁻¹, and 5 females; $\dot{\mathrm{V}}{\mathrm{O}}_2\text{max}$  = 67.3 [2.9] mL·min⁻¹·kg⁻¹, MAP = 261 [17] W, 5.0 [0.1] W·kg⁻¹) participated over 4 seasons at several (119) international and national races and performed laboratory tests regularly to assess their aerobic and anaerobic performance. Power output, heart rate, and cadence were recorded throughout the races. Results: The mean race time was 79 (12) minutes performed at a mean power output of 3.8 (0.4) W·kg⁻¹; 70% (7%) MAP (3.9 [0.4] W·kg⁻¹ and 3.6 [0.4] W·kg⁻¹ for males and females, respectively) with a cadence of 64 (5) rev·min⁻¹ (including nonpedaling periods). Time spent in intensity zones 1 to 4 (below MAP) were 28% (4%), 18% (8%), 12% (2%), and 13% (3%), respectively; 30% (9%) was spent in zone 5 (above MAP). The number of efforts above MAP was 334 (84), which had a mean duration of 4.3 (1.1) seconds, separated by 10.9 (3) seconds with a mean power output of 7.3 (0.6) W·kg⁻¹ (135% [9%] MAP). Conclusions: These findings highlight the importance of the anaerobic energy system and the interaction between anaerobic and aerobic energy systems. Therefore, the ability to perform numerous efforts above MAP and a high aerobic capacity are essential to be competitive in mountain bike cross-country.

This study was done to determine the extent to which body composition accounts for differences in anaerobic characteristics between 12-year-old girls and boys. Peak leg power (PP), mean leg power (MP), percent body fat, fat free mass (FFM), and lean thigh volume (LTV) were determined by various tests. Pubertal stages and salivary testosterone concentration (in boys) were used to assess sexual maturation. Laboratory anaerobic indices were compared with performances in two running tests. Blood samples were taken for lactate determination. Absolute PP and MP outputs were similar in both sexes and were better correlated with LTV in girls, whereas in boys both PP and MP were highly correlated with FFM. Although nonsignificant gender difference in lean tissue was observed, PP and MP when corrected for LTV were significantly greater in boys than in girls. Factors other than the amount of lean muscle mass should be considered in explaining the gender differences in PP and MP in early pubertal children.