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

Abstract

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 O₂ extraction, and reduced perceived fatigability in people with chronic cervical motor-incomplete SCI following the OLT program described in this study.

Keywords:

• Overground locomotor training
• Oxygen uptake
• Endurance
• Perceived fatigability

Acknowledgements

The authors would like to acknowledge the participants and graduate students for their time and commitment to this project. Information contained in this manuscript has been presented, in part, at the American College of Sports Medicine (ACSM) Annual Conference, American Congress of Rehabilitation Medicine (ACRM) Annual Meeting, American Physical Therapy Association (APTA) NEXT Conference, American Spinal Injury Association (ASIA) Annual Conference, and the American Society of Biomechanics Annual Conference, either as Poster or Symposium presentations.

Disclaimer statements

Conflict of interests None.

Contributors None.

Funding None.

Suppliers list

1. Oxymon MK-III, Artinis Medical Systems, The Netherlands

2. Trackmaster Treadmill TMX22

3. Ultima™ CardiO₂®, Medical Graphics Corp, St. Paul, MN, USA

4. Mortara ECG, Milwaukee, WI, USA