Effect of warm-up on cycle time trial preformance.

Purpose: This study was designed to determine the effect of warm-up on 3-km cycling time trial (TT) performance, and the influence of accelerated V

Breaking away: effects of non-uniform pacing on power output and RPE growth.

The rating of perceived exertion (RPE) normally grows as a scalar function of relative competitive distance, suggesting that it may translate between the brain and body relative to managing fatigue during time-trial exercise. In nonstandard pacing situations, a reciprocal relationship between RPE and power output (PO) would be predicted.Purpose:To determine whether PO would decrease when RPE was forced above the normal growth curve during a cycle time trial.Methods:Well-trained cyclists performed randomly ordered 10-km cycle time trials. In CONTROL they rode at their own best pace throughout. In BURST, they made a 1-km “burst” at the 4-km mark and then finished as rapidly as possible.Results:CONTROL was significantly (P &lt; .05) faster than BURST (16:36 vs 17:00 min). During CONTROL, responses between 4 and 5 km were PO, 240 W; RPE, 5–6; and blood lactate [HLa], 8–9 mmol/L. During BURST PO increased to 282 W, then fell to 220 W after the burst and remained below CONTROL until the end spurt (9 km). RPE increased to 9 during the burst but returned to the normal RPE growth pattern by 6 km; [HLa] increased to ~13 mmol/L after the burst and remained elevated throughout the remainder of the trial.Conclusions:The reciprocal behavior of RPE and PO after BURST supports the hypothesis that RPE translates between the brain and the body during heavy exercise. However, the continuing reduction of PO after the burst, even after RPE returned to its normal growth pattern, suggests that PO is regulated in a more complex manner than reflected solely by RPE.</jats:sec

Effect of competitive distance on energy distribution during simulated competition

Concepts of how athletes should expend their aerobic and anaerobic energetic reserves are generally based on results of tests where an "all out" strategy is imposed on/required from the athlete. We sought to determine how athletes spontaneously expend their energetic reserves when the only instruction was to finish the event in minimal time, as in competition. Well trained, and task habituated, road cyclists (N = 14) completed randomly ordered laboratory time trials of 500 m, 1000 m, 1500 m and 3000 m on a windload braked cycle ergometer. The pattern of aerobic and anaerobic energy use was calculated from total work accomplished and V̇

The Effect of Music on Time Trial Performance.

Music is widely used as an ergogenic aid in sport, but there is little evidence of its effectiveness during closedloop athletic events. In order to determine the effectiveness of music as an ergogenic aid, well-trained and task-habituated cyclists performed 10-km cycle time trials either while listening to self-selected motivational music or with auditory input blocked. There were no statistically significant differences in performance time or physiological or psychological markers related to music (time-trial duration 17.75 ± 2.10 vs 17.81 ± 2.06 min, mean power output 222 ± 66 vs 220 ± 65 W, peak heart rate 184 ± 9 vs 183 ± 8 beats/min, peak blood lactate 12.1 ± 2.6 vs 11.9 ± 2.1 mmol/L, and final rating of perceived exertion 8.4 ± 1.5 vs 8.5 ± 1.6). It is concluded that during exercise at competitive intensity, there is no meaningful effect of music on either performance or physiology.</jats:p

VO2max during successive maximal efforts.

The concept of VO(2)max has been a defining paradigm in exercise physiology for >75 years. Within the last decade, this concept has been both challenged and defended. The purpose of this study was to test the concept of VO(2)max by comparing VO(2) during a second exercise bout following a preliminary maximal effort exercise bout. The study had two parts. In Study #1, physically active non-athletes performed incremental cycle exercise. After 1-min recovery, a second bout was performed at a higher power output. In Study #2, competitive runners performed incremental treadmill exercise and, after 3-min recovery, a second bout at a higher speed. In Study #1 the highest VO(2) (bout 1 vs. bout 2) was not significantly different (3.95 +/- 0.75 vs. 4.06 +/- 0.75 l min(-1)). Maximal heart rate was not different (179 +/- 14 vs. 180 +/- 13 bpm) although maximal V(E) was higher in the second bout (141 +/- 36 vs. 151 +/- 34 l min(-1)). In Study #2 the highest VO(2) (bout 1 vs. bout 2) was not significantly different (4.09 +/- 0.97 vs. 4.03 +/- 1.16 l min(-1)), nor was maximal heart rate (184 + 6 vs. 181 +/- 10 bpm) or maximal V(E) (126 +/- 29 vs. 126 +/- 34 l min(-1)). The results support the concept that the highest VO(2) during a maximal incremental exercise bout is unlikely to change during a subsequent exercise bout, despite higher muscular power output. As such, the results support the "classical" view of VO(2)max.1.752 JCR (2007) Q1, 14/72 Sport sciences; Q3, 44/78 PhysiologyUE

Perception of fatigue during simulated competition

BACKGROUND: Previous studies suggest that the rating of perceived exertion (RPE) increases during steady-state, open-loop exercise in proportion to the relative time to fatigue. This suggests that RPE is scalar and integrates physiological status and homeostatic disturbances. PURPOSE: This study assessed the relationship between the rate of change in RPE, and relative distance in time trials at distances of 2.5, 5, and 10 km. It also assessed the rate of change in RPE during 5-km time trials while breathing hypoxic air. METHODS: The subjects were well-conditioned cyclists. In part 1, each subject completed habituation time trials, and then randomly ordered time trials at each distance. The category ratio RPE was measured in 10% increments throughout each trial. In part 2, each subject completed three 5-km time trials while breathing different inspired gas mixtures (FiO2 = 0.2093 throughout the trial, FiO2 = 0.15 between 2 and 4 km, and FiO2 = 0.15 between 2.5 and 4 km). RPE was measured at 10% increments. RESULTS: In part 1, when RPE was plotted against relative distance, there was no significant difference in the growth of RPE at proportional distances. In part 2, the decrease in power output during the hypoxic segments was sufficient that the growth of RPE was the same at each proportional distance. In both parts of the study, an RPE of 5 (hard) was achieved after 20% of the time trial distance, and an RPE of 8 was achieved after 80% distance. CONCLUSIONS: This study supports the hypothesis that RPE increases similarly in relation to relative distance, regardless of the distance performed, and it suggests that the perception of effort has scalar properties. ©2008The American College of Sports Medicine