Exercise tolerance during flat over-ground intermittent running: modelling the expenditure and reconstitution kinetics of work done above critical power

Abstract

Purpose We compared a new locomotor-specific model to track the expenditure and reconstitution of work done above critical power ( W´ ) and balance of W´ ( W´ BAL ) by modelling flat over-ground power during exhaustive intermittent running. Method Nine male participants completed a ramp test, 3-min all-out test and the 30–15 intermittent fitness test (30–15 IFT), and performed a severe-intensity constant work-rate trial ( S CWR ) at the maximum oxygen uptake velocity ( vV̇ O 2max ). Four intermittent trials followed: 60-s at vV̇ O 2max + 50% Δ 1 (Δ 1 = vV̇ O 2max − critical velocity [ V Crit ]) interspersed by 30-s in light ( S L ; 40% vV̇ O 2max ), moderate ( S M ; 90% gas-exchange threshold velocity [ V GET ]), heavy ( S H ; V GET + 50% Δ 2 [Δ 2 = V Crit − V GET ]), or severe (S S ; vV̇ O 2max − 50% Δ 1 ) domains. Data from Global Positioning Systems were derived to model over-ground power. The difference between critical and recovery power ( D CP ), time constant for reconstitution of W´ ( $$\tau_{{W^{\prime}}}$$ τ W ′ ), time to limit of tolerance ( T LIM ), and W´ BAL from the integral ( W´ BALint ), differential ( W´ BALdiff ), and locomotor-specific (OG- W´ BAL ) methods were compared. Results The relationship between $$\tau_{{W^{\prime}}}$$ τ W ′ and D CP was exponential ( r 2 = 0.52). The $$\tau_{{W^{{\prime}}}}$$ τ W ′ for S L , S M , and S H trials were 119 ± 32-s, 190 ± 45-s, and 336 ± 77-s, respectively. Actual T LIM in the 30–15 IFT (968 ± 117-s) compared closely to T LIM predicted by OG- W´ BAL (929 ± 94-s, P > 0.100) and W´ BALdiff (938 ± 84-s, P > 0.100) but not to W´ BALint (848 ± 91-s, P = 0.001). Conclusion The OG- W´ BAL accurately tracked W´ kinetics during intermittent running to exhaustion on flat surfaces.

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