Modeling the Recovery of W′ in the Moderate to Heavy Exercise Intensity Domain

Purpose This study (i) investigates the effect of recovery power (P-rec) and duration (t(rec)) on the recovery of the curvature constant (W ') of the power-duration relationship, (ii) compares the experimentally measured W ' balance to that predicted (W '(bal)) by two models (SK2 and BAR), and (iii) presents a case of real-time performance optimization using the critical power (CP) concept. Methods Seven competitive amateur cyclists performed a ramp test to determine their VO2peak and gas exchange threshold, two to four 3-min all-out tests to determine CP and W ', and nine intermittent cycling tests to investigate W ' recovery. The intermittent cycling tests involved a 2-min constant work-rate interval above CP, followed by a constant work-rate recovery interval below CP (P-rec and t(rec) were varied), followed by a 3-min all-out interval. Results There was a significant two-way interaction between P-rec and t(rec) on W ' recovery, P = 0.004 (eta(2) = 0.52). Simple main effects were present only with respect to P-rec at each t(rec). The actual W ' balance at the end of the recovery interval was less than the W '(bal) predicted by both SK2 (P = 0.035) and BAR (P = 0.015) models. The optimal strategy derived from the subject-specific recovery model reduced the race time by 55 s as compared with the self-strategy. Conclusions This study has shown that in a recovery interval, P-rec has a greater influence than t(rec) on W ' recovery. The overprediction of W '(bal) from SK2 and BAR suggests the need for individualized recovery parameters or models for sub-CP exercise. Finally, the optimal strategy results provide encouraging signs for real-time, model-based performance optimization.