Characterization of muscle oxygenation response in well-trained handcyclists

Purpose: Peripheral responses might be important in handcycling, given the involvement of small muscles compared to other exercise modalities. Therefore, the goal of this study was to compare changes in muscle oxygen saturation (∆SmO₂) and deoxyhemoglobin level (∆[HHb]) between different efforts and muscles.

Methods: Handcyclists participated in a Wingate, a maximal incremental test and a 20-min time-trial (TT). Oxygen uptake (VO₂) as well as ∆SmO₂, ∆[HHb], deoxygenation and reoxygenation rates in the triceps brachii (TB), biceps brachii (BB), anterior deltoid (AD) and extensor carpi radialis brevis (ER) were measured.

Results: ER ∆[HHb]max was 37% greater in the incremental test than in the Wingate (ES = 0.392, P = 0.031). TT mean power (W/kg) was associated with BB ∆SmO₂min measured in the incremental test (r = -0.998 [-1.190, -0.806], P = 0.002) and in the Wingate (r = -0.994 [-1.327, -0.661], P = 0.006). MAP (W/kg) was associated with Wingate BB ∆SmO₂min (r = -0.983 [-0.999, -0.839], P = 0.003), and Wingate peak (r = 0.649 [0.379, 0.895], P = 0.008) and mean power (W/kg) (r = 0.925 [0.752, 0.972], P = 0.003) was associated with right handgrip force. The strongest physiological predictor for TT performance was BB ∆SmO₂min in the incremental test (P = 0.002, r² = 0.993, SEE 0.016 W/kg), Wingate BB ∆SmO₂min for MAP (P = 0.003, r² = 0.956, SEE 0.058 W/kg) and right handgrip force for Wingate peak power (P = 0.005, r² = 0.856, SEE 0.551 W/kg).

Conclusion: Peripheral aerobic responses (muscle oxygenation) were predictive of handcycling performance.