Arm position but not handedness modulates forearm oxygen recovery dynamics in rock climbers

Background: Forearm muscle oxygen recovery is a key determinant of fatigue resistance in climbing, yet most assessments are performed in positions that do not reflect actual climbing demands. The influence of handedness on oxygen recovery dynamics also remains unclear. This study examined the effects of upper-limb position and handedness on forearm oxygen recovery in climbers of different ability levels. Methods: Fifty-one male participants, elite climbers (n = 20), intermediate climbers (n = 21), and non-climbing controls (n = 10), completed bilateral arterial occlusion tests in two randomized positions: supine with the arms along the body and seated with the arms elevated to 180° of shoulder flexion. Tissue oxygen saturation (StO₂) over the flexor digitorum profundus was measured using near-infrared spectroscopy. Half-time recovery and reoxygenation rate were calculated after cuff release. Wilcoxon tests assessed the effects of position and handedness, while the Kruskal-Wallis test evaluated group differences. Results: Arm elevation substantially slowed oxygen recovery in both limbs. StO₂ half-time recovery increased from 10.7 ± 2.9 s to 30.3 ± 25.0 s in the dominant and from 10.4 ± 2.4 s to 29.3 ± 22.7 s in the non-dominant limb ( p  < 0.001). StO₂ rate decreased from 1.50 ± 0.51 to 0.68 ± 0.7 %/s in the dominant and from 1.62 ± 0.58 to 0.65 ± 0.6 %/s in the non-dominant limb ( p  < 0.001). Inter-individual variability was large, with recovery slowing up to 12.6-fold in the elevated position. Handedness had no meaningful influence on oxygen-recovery outcomes at either position ( p  = 0.126–0.830). Climbing ability did not affect recovery dynamics, with similar values across elite, intermediate, and control groups ( p  = 0.204–0.704). Conclusions: Arm elevation markedly impairs forearm oxygen-recovery dynamics by slowing the restoration of oxygen availability in the forearm flexors, suggesting that reoxygenation is highly sensitive to limb position. The present study introduces an ecologically valid arterial occlusion-reoxygenation test performed with the arm elevated to capture these position-dependent responses in overhead athletes.