Exploring the Pacing Landscape
Jos J. de Koning, Carl Foster, Florentina Johanna Hettinga · Medicine & Science in Sports & Exercise · 2011
BACKGROUND: Athletic performance depends both on the rate at which energy can be expended and on the distribution of energy during an event (pacing strategy). Laboratory and modeling studies suggest that the optimal strategy for expending energy depends on the duration of an athletic event and the % relative distance completed. Experienced athletes choose, by learning or 'natural feel', a strategy that is close to the theoretical optimum. Thus, it can be hypothesized that athletes have a reference motor 'landscape' that guides performance during time trials of different distances. PURPOSE: To explore the relationships between time trial distance and distribution of power output, neural input and the resultant velocity profile. METHODS: Trained male cyclists (n=9) completed maximal incremental exercise (VO2max = 4.5 ± 0.2 l·min-1; peak power output (PPO) = 383 ± 26 W). After habituation, they completed randomly ordered cycle ergometer time trials of 750m, 1500m, 2500m and 4000m. Velocity, power output, pedal torque and surface EMG of the medial and lateral vastus and the rectus femoris were measured. Power output was expressed as %PPO. EMG was rectified, filtered and normalized to maximal voluntary contraction (%MVC). RESULTS: The time trials were completed in 57.2 ± 1.7 s, 116.3 ± 1.7 s, 198.5 ± 4.9 s and 325.3 ± 9.4 s. The relationship between time trial distance, relative distance completed and relative power and EMG is presented in the figure. CONCLUSSION: The data supports the hypothesis that there is an underlying landscape that guides motor unit recruitment and muscular power output use during time trials of different distances.Figure