Abstract Information

P-77

Alternative ways to exercise after SCI- Overground cycling with electrical stimulation without motor assistance- Case Study

1Lombardo L, 1Foglyano K, 1Bailey S, 1Triolo R, 2McDaniel J
1Louis Stokes Cleveland VA Medical Center, Clevleland, Ohio, USA; 2Kent State University, Kent, Ohio, USA

Introduction: Immobility following paralysis compromises physical activity, leading to long-term health complications such as cardiovascular and pulmonary disease, and diabetes. Individuals with SCI experience significant barriers to exercise which can lead to secondary health complications as well as decreased self-confidence, depression, and overall poor health. Adapted exercise equipment for persons with SCI is often restricted to specialized gyms, requires assistance, and may not provide the intensity needed for the global health benefits of exercising the lower extremity muscles. Stimulation-driven over-ground cycling may be an effective new modality for exercise and recreation after SCI.
Case presentation: Two male recipients of implanted neuroprostheses (NP) targeting muscles necessary for standing/stepping participated. Subject 1 was 57 years old, 8 years post T11 AIS B injury, and a consistent NP user for 6 years. Subject 2 was 60 years old, 9 year post T4 AIS B injury, and a regular NP user for 5 years. Both previously used their NPs for exercise, standing and stepping, and were conditioned enough to stand for >30 minutes at a time.
Diagnostic: We collected max and mean power and speed pre- and post-training with custom-instrumented commercially available stimulation-driven recumbent tricycles. We also calculated steady state power after initial peak power surge to document endurance and ability to maintain power output over time.
Therapeutic: Stimulation was delivered to gluteus maximus, posterior adductor magnus, semimembranosus, and quadriceps by multichannel implanted pulse generators via muscle or nerve based electrodes. Stimulus timing and intensity were customized and coordinated with crank angle to produce continuous cycling motions. We developed training protocols for fatigue resistance and power production. Strengthening exercise consisted of 60 secs of stimulated cycling followed by 30 secs rest while endurance exercise consisted of 10 mins of cycling followed by 5 mins rest. Subjects were instructed to use the hardest gear ratio possible that still allowed cycling for one hour per protocol. Exercises were performed 3-4 times/week for 16 weeks on a stationary trainer, or over-ground outdoors.
Results: Both subjects made significant gains in all outcome measures over baseline. Subject 1 increased max power from 81 to 134 W (65%); max speed from 10.6 to 12.6 mph (18%); mean power from 29.0 to 40.0 W (38%); mean speed from 6.8 to 8.3 mph (22%); and steady state power from 17 to 26.6 W (56%). Subject 2 improved max power from 41 to 70 W (71%); max speed from 8.3 to 10.7 mph (29%); mean power from 20.0 to 39.4 W (97%); mean speed from 7.2 to 7.7 mph (7%); and steady state power from 17.6 to 32.9 W (87%).
Discussion: Individuals with SCI have difficulty exercising, resulting in major health problems. Finding ways for this population to have access to exciting, easy-to-use and effective modes of exercise is critical for their wellbeing. Even well-conditioned, regular users of stimulation for exercise can improve peak cycling power by 68% after 16 weeks of training, and increase fatigue resistance (steady state power) by 72%, which was sufficient to enable outdoor cycling over level ground for more than an hour.


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