Physiological responses during simulated 16 km recumbent handcycling time trial and determinants of performance in trained handcyclists

Purpose: To characterise the physiological profiles of trained handcyclists, during recumbent handcycling, to describe the physiological responses during a 16 km time trial (TT) and to identify the determinants of this TT performance.

Methods: Eleven male handcyclists performed a sub-maximal and maximal incremental exercise test in their recumbent handbike, attached to a Cyclus II ergometer. A physiological profile, including peak aerobic power output (PO_Peak), peak rate of oxygen uptake (V̇O_2Peak), aerobic lactate threshold (AeLT) and PO at 4 mmol∙L^-1 (PO₄), were determined. Participants also completed a 16 km simulated TT using the same experimental set-up. Determinants of TT performance were identified using stepwise multiple linear regression analysis.

Results: Mean values of PO_Peak = 252 ± 9 W, V̇O_2Peak = 3.30 ± 0.36 L·min^-1 (47.0 ± 6.8 mL·kg^-1·min^-1), AeLT = 87 ± 13 W and PO₄ = 154 ± 14 W were recorded. The TT was completed in 29:21 ± 0:59 min:s at an intensity equivalent to 69 ± 4% PO_Peak and 87 ± 5% V̇O_2Peak. PO_Peak (r = -0.77, P=0.006), PO₄ (r = -0.77, P=0.006) and AeLT (r = -0.68, P=0.022) were significantly correlated with TT performance. PO₄ and PO_Peak were identified as the best predictors of TT performance (r = 0.89, P<0.001).

Conclusion: PO_Peak, PO₄ and AeLT are important physiological TT performance determinants in trained handcyclists, differentiating between superior and inferior performance whereas V̇O_2peak was not. The TT took place at an intensity corresponding to 69% PO_Peak and 87% V̇O_2peak.