# Feasibility, acceptability, and preliminary efficacy of a handcycling high-intensity interval training program for individuals with spinal cord injury

PMID: 32908194
Journal: Spinal Cord
Published: 2020-09-09
Authors: Koontz AM, Garfunkel CE, Crytzer TM, Anthony SJ, Nindl BC

## Question

Is a home-based handcycling HIIT program feasible, acceptable, safe, and preliminarily effective for individuals with spinal cord injury?

## Summary

A small pilot trial tested 6 weeks of at-home supervised handcycling HIIT for wheelchair users with spinal cord injury. Most completers attended the supervised sessions and rated the program highly, and no study-related adverse events occurred. Group-level fitness outcomes did not significantly improve, and the study had no control group.

## Population

- Ten manual wheelchair users with spinal cord injury enrolled; seven completed. Mean age was 39.4 +/- 14.2 years; 7 male and 3 female; 7 tetraplegia and 3 paraplegia; 8 had incomplete injuries; mean time since injury was 12.4 +/- 10.6 years.
- Sample size: 10
- Age: 39.4 +/- 14.2 years
- Sex: 7 male, 3 female
- Fitness level: Manual wheelchair users; 8 already reported regular physical activity
- Health status: Spinal cord injury at least 6 months; 7 tetraplegia, 3 paraplegia

## Methodology

- Pilot non-randomized clinical trial
- 6 weeks
- Participant homes

## Protocol

- At-home handcycling HIIT; details: Six-week at-home handcycling HIIT: two supervised 25-min sessions/week using a handcycle or add-on handbike on a stationary roller. Sessions included 2-3 min warm-up, 10 x 1 min at 90% peak power output (+/- 5 W) with 1 min recovery at 0-20% PPO, and 2-3 min cooldown. RPE or observed performance could prompt 10-15 W target adjustments.
- Modality: Handcycling HIIT.
- Work intervals: 1 min.
- Recovery: 1 min.
- Sets or repetitions: 10 intervals per session.
- Intensity: Work intervals at 90% peak power output +/- 5 W; recovery at 0-20% PPO; intensity criteria included HR >=90% HRmax and RPE >=17 for final intervals.
- Session duration: 25 min.
- Frequency: 2 supervised sessions, optional additional unsupervised sessions.
- Program length: 6 weeks.
- Progression: Power targets could be adjusted by 10-15 W based on RPE/visual cues.

## Outcomes

### Seven of ten participants completed the program.
Status: mixed
Seven of ten participants completed the program.

### Attendance
Status: mixed
Six of seven completers attended all minimum supervised sessions; one completed 50% because of personal/work scheduling.

### Intensity fidelity
Status: mixed
Of 89 sessions, 76 (85.4%) met at least one HIIT intensity criterion; 61.8% met at least two criteria and 23.6% met all three.

### Enjoyment and satisfaction
Status: mixed
PACES enjoyment total was 114.8 +/- 11.3 out of a possible 126, and all survey respondents were very satisfied with HIIT and the trainer.

### Fitness outcomes
Status: mixed
Fitness changes were not statistically significant among participants completing at least 12 sessions: peak VO2 was 14.3 +/- 5.0 to 14.3 +/- 4.8 mL/kg/min (p=.931), peak power output 60.0 to 65.0 W (p=.203), and time to exhaustion 6:17 to 6:49 (p=.194).

p=.931

## Practical Insights

- Adaptive HIIT can be highly acceptable when equipment and supervision are tailored to participants.
- Feasibility evidence should not be converted into fitness efficacy claims because group-level fitness outcomes did not significantly change.
- For users with SCI, HR and RPE alone may be insufficient; power targets and individualized monitoring are useful.

## Limitations

- Very small non-randomized pilot with no control group.
- Mostly participants with incomplete injuries and many already physically active.
- Specialized equipment and transfers may limit scalability.
- HR and RPE may be unreliable in SCI.
- Training mode differed from testing mode and 1-min upper-body intervals may have been too short.

## Safety And Adherence

- No study-related adverse events occurred.
- Dropouts included a pressure ulcer unrelated to study after 6 sessions, a new job after baseline, and a fall outside the study with femur fracture during the first week.

## Original Sources

- [PubMed](https://pubmed.ncbi.nlm.nih.gov/32908194/) (pubmed)
- [DOI](https://doi.org/10.1038/s41393-020-00548-7) (doi)
- [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7854955/) (full text)

## Agent Guidance

Preserve the paper-level scope of this note. Do not generalize beyond the population, protocol, measured outcomes, and limitations above.