Peak power output, the lactate threshold, and time trial performance in cyclists

Area of Science:

• Exercise Physiology
• Sports Science
• Biochemistry

Background:

• Understanding the physiological determinants of endurance performance is crucial for optimizing training in cyclists.
• Lactate thresholds and maximal power output are commonly used metrics to assess cycling performance.

Purpose of the Study:

• To investigate the relationship between various exercise intensity markers and average power output in different time trial durations among well-trained cyclists.
• To determine how maximal workload (W(peak)), workload at lactate onset (W(OBLA)), and different lactate thresholds (W(LTlog), D(max)) relate to 20-minute (W(20-min)) and 90-minute (W(90-min)) time trial performance.

Main Methods:

• Nine male cyclists with high maximal oxygen uptake (.VO(2max)) performed incremental ramp tests and 20-minute and 90-minute time trials on an ergometer.
• Measurements included W(peak), W(OBLA), W(LTlog), D(max) lactate threshold, .VO(2max), and average power output for each time trial.

Main Results:

• Average power output during the 90-minute time trial (W(90-min)) strongly correlated with W(peak) (r=0.91) and W(LTlog) (r=0.91).
• The 20-minute time trial (W(20-min)) showed significant correlations with .VO(2max) (L/min) (r=0.69) and W(LTlog) (r=0.67).
• W(OBLA) and .VO(2max) (mL/kg/min) did not significantly correlate with either W(90-min) or W(20-min).

Conclusions:

• In subelite cyclists, the relationship between maximal power output and lactate threshold power output can vary based on time trial duration.
• These findings suggest that different physiological factors may influence performance in shorter versus longer cycling time trials.