Walking endurance, muscle oxygen extraction, and perceived fatigability after overground locomotor training in incomplete spinal cord injury: A pilot study

Objective:The purpose of this study was to examine the effects of overground locomotor training (OLT) on walking endurance and gastrocnemius oxygen extraction in people with chronic cervical motor-incomplete spinal cord injury (SCI). Design:Prospective single-arm pre-post pilot study. Setting:Human Performance Research Laboratory. Participants:Adult men with traumatic chronic cervical SCI (n = 6; age = 30.8 +/- 12.5). Intervention:Twenty-four sessions of structured OLT. Outcome measures:Walking endurance was determined during a constant work-rate time-to-exhaustion treadmill test. Normalized perceived fatigability was calculated by dividing subjective ratings of tiredness by walking time. Cardiorespiratory outcomes and muscle oxygen extraction were analyzed using breath-by-breath gas-exchange and near-infrared spectroscopy. Results:OLT resulted in large effects on walking endurance (1232 +/- 446 s vs 1645 +/- 255 s;d = 1.1;P = 0.045) and normalized perceived fatigability (5.3 +/- 1.5 a.u. vs 3.6 +/- 0.9 a.u.;d = 1.3;P = 0.033). Small-to-medium effects on absolute (2.8 +/- 2.5 a.u. vs 4.2 +/- 3.5 a.u.;d = 0.42;P = 0.035) and isotime (2.8 +/- 2.5 a.u. vs 3.8 +/- 3.0 a.u.;d = 0.33;P = 0.023) muscle oxygen extraction were also observed after OLT. Conclusion:These findings provide preliminary data supporting the potential for improved walking endurance, enhanced muscle O(2)extraction, and reduced perceived fatigability in people with chronic cervical motor-incomplete SCI following the OLT program described in this study.