Timing and dosage of FES cycling early after acute spinal cord injury: A case series report

Abstract

Objective

To understand the progression in parameters of functional electrical stimulation (FES) cycling dosage (including duration, velocity, stimulation amplitudes, power output), and the resulting changes in muscle mass early after acute spinal cord injury (SCI).

Methods

Three participants, 24–38 years old, with neurological injury level C4–T4, severity AIS (American Spinal Injury Association Impairment Scale) A–C, started FES cycling 16–20 days post injury while admitted at a level-1 trauma center in Canada, and continued for 8–13 weeks in a rehabilitation hospital. They performed three sessions/week of 15–45 min FES cycling, supine or sitting. FES parameters, cycling performance, and muscle cross-sectional area (CSA) in thighs and calves were measured every 2 weeks.

Results

Progression in power output, but not in session duration, was limited in two participants who experienced stimulation-associated referred pain or apprehension, requiring limitation of stimulation amplitudes for up to 65 days after the start of FES cycling. Participants started with 15 min cycling at 20 RPM with no resistance (0 W), and progressed to 30–45 min at 30 RPM producing 8.8–19.0 W average power/session after 2–3 months. Initially, muscle CSA decreased in all 3 participants (up to 16% after 6 weeks), and recovered later after a variable period of FES cycling (up to 16% at 13.3 weeks).

Conclusion

Progression of FES cycling in the first 3 months after injury required a highly individualized approach, guided by participant response, rather than standardized increments in stimulation intensity or duration. Changes in muscle CSA did not always correspond with the dose of FES cycling.

Keywords:

• Acute spinal cord injury
• FES cycling
• Early exercise
• Muscle atrophy
• Dosage

Acknowledgements

The authors wish to thank the Spinal Cord Injury Treatment (Northern Alberta) Society (SCITCS) for providing the FES cycling equipment, and the management teams and frontline clinicians at the University of Alberta Hospital and Glenrose Rehabilitation Hospital for their support.

Disclaimer statements

Contributors: None.

Funding: This work was supported by the University of Alberta Endowed Spinal Cord Research Chair funding.

Conflict of interest: Authors have no conflict of interest to declare.