Muscle oxygenation during hybrid arm and functional electrical stimulation–evoked leg cycling after spinal cord injury

This study compared muscle oxygenation (StO(2)) during arm cranking (ACE), functional electrical stimulation–evoked leg cycling (FES-LCE), and hybrid (ACE+FES-LCE) exercise in spinal cord injury individuals. Eight subjects with C7-T12 lesions performed exercises at 3 submaximal intensities. StO(2) was measured during rest and exercise at 40%, 60%, and 80% of subjects’ oxygen uptake (VO(2)) peak using near-infrared spectroscopy. StO(2) of ACE showed a decrease whereas in ACE+FES-LCE, the arm muscles demonstrated increasing StO(2) from rest in all of VO(2)) peak respectively. StO(2) of FES-LCE displayed a decrease at 40% VO(2) peak and steady increase for 60% and 80%, whereas ACE+FES-LCE revealed a steady increase from rest at all VO(2) peak. ACE+FES-LCE elicited greater StO(2) in both limbs which suggested that during this exercise, upper- and lower-limb muscles have higher blood flow and improved oxygenation compared to ACE or FES-LCE performed alone.