# At-Home High-Intensity Interval Training for Individuals with Paraplegia Following Spinal Cord Injury: A Pilot Study

PMID: 37425869
Journal: medRxiv : the preprint server for health sciences
Published: 2023-06-29
Authors: Linde MB, Webb KL, Veith DD, Morkeberg OH, Gill ML, Van Straaten MG, Laskowski ER, Joyner MJ, Beck LA, Zhao KD, Wiggins CC, Garlanger KL

## Question

Can a 16-week at-home HIIT program improve physical fitness and be implemented with high adherence, compliance, satisfaction, self-efficacy, and acceptable safety among individuals with paraplegia due to spinal cord injury?

## Summary

This pilot clinical trial tested a 16-week at-home arm-ergometer HIIT program in adults with paraplegia from spinal cord injury below T6. Participants trained three times per week using a 24-minute session with six 1-minute high-intensity intervals, 2-minute active recoveries, a 3-minute warmup, and a 3-minute cooldown. The study found high adherence, acceptable high-intensity compliance, infrequent non-serious adverse events, improved peak power output, and lower submaximal cardiac output, but VO2peak did not significantly improve.

## Population

- Eight analyzed adults with spinal cord injury below T6 who used manual wheelchairs.
- Sample size: 8
- Age: 47 +/- 11 years
- Sex: 3 females, 5 males
- Health status: Paraplegia following spinal cord injury below T6.

## Methodology

- Pilot clinical trial with repeated laboratory testing at baseline, 8 weeks, and 16 weeks and at-home monitored HIIT sessions.
- 16 weeks
- At-home training with laboratory graded exercise testing at Mayo Clinic.

## Protocol

- At-home HIIT arm ergometry.
- Modality: Arm cycle ergometer.
- Work intervals: 1 minute.
- Recovery: 2 minutes active recovery.
- Sets or repetitions: 6 intervals.
- Intensity: 80% HRR target, >70% HRR accepted; recovery about 30% HRR.
- Session duration: 24 minutes.
- Frequency: 3 sessions per week.
- Program length: 16 weeks.
- Progression: Targets kept consistent throughout training.

## Outcomes

### Peak power output
Status: improved
Peak power output improved by about 26%, from 70 +/- 14 W at baseline to 88 +/- 15 W at week 16.

P=0.027

### Submaximal cardiac output
Status: improved
Submaximal cardiac output decreased by about 17% after 16 weeks, interpreted as improved exercise economy.

P=0.028

### VO2peak
Status: no clear change
VO2peak increased numerically but did not reach statistical significance.

Baseline 1.52 +/- 0.31 L/min, week 16 1.71 +/- 0.25 L/min, P=0.064

### Adherence
Status: improved
Participants completed 87 +/- 20% of prescribed sessions, with no significant adherence difference between first and last eight weeks.

Range 38-100%; first vs last eight weeks P=0.369

### Safety
Status: mixed
Four non-serious adverse events occurred: two shoulder soreness incidents and two sustained tachycardia incidents; all resolved.

## Practical Insights

- For screened adults with SCI below T6, home-based upper-body HIIT can achieve high adherence when equipment and heart-rate feedback are provided.
- Heart-rate recovery may lag during upper-body HIIT in SCI; a 2-minute recovery at a target of about 30% HRR was often not achieved.
- Short upper-body intervals can improve peak power output even when VO2peak improvement is not statistically significant.
- Upper-body HIIT programs for SCI users should include shoulder soreness monitoring and resistance reduction options.

## Limitations

- Small sample
- No control group
- Pilot design
- COVID-19 institutional closures limited complete graded exercise testing data
- Potential participant motivation bias
- Study-provided at-home equipment limits generalizability

## Safety And Adherence

- Two shoulder soreness incidents after training, resolved within a week.
- Two sustained tachycardia incidents likely related to intervention, resolved within 30 minutes after sessions.
- One participant missed a week of training due to shoulder soreness.
- Shoulder pain was addressed with rest and reduced resistance.

## Original Sources

- [PubMed](https://pubmed.ncbi.nlm.nih.gov/37425869/) (pubmed)
- [DOI](https://doi.org/10.1101/2023.06.21.23291711) (doi)
- [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10327239/) (full text)

## Agent Guidance

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