Effects of Intramuscular Trunk Stimulation on Manual Wheelchair Propulsion Mechanics in Six Subjects with Spinal Cord Injury

Arch Phys Med Rehabil, 2013 · DOI: 10.1016/j.apmr.2013.04.010 · Published: October 1, 2013

Spinal Cord Injury Assistive Technology Rehabilitation

Simple Explanation

This study investigates whether electrical stimulation of trunk and hip muscles can improve wheelchair propulsion for people with spinal cord injuries. The goal is to stabilize the torso, which can reduce strain on the upper body during wheelchair use. The researchers measured several factors related to wheelchair propulsion, such as pushrim force, shoulder moment, trunk lean, and efficiency, with and without stimulation. Subjects also rated how difficult it was to propel the wheelchair during sprints and ramp ascents. The results showed that stimulation can improve propulsion efficiency and reduce perceived effort in some individuals during level ground propulsion. However, the benefits were less clear during more challenging activities like sprinting and ramp climbing.

Study Duration

Not specified

Participants

Six (4M, 2F age 46±10.8yrs) long-time users

Evidence Level

Level 4, Single-subject design case series

Key Findings

1
Three out of five subjects demonstrated reduced peak resultant pushrim forces and improved efficiency with stimulation during self-paced level propulsion.
2
Maximal forward trunk lean also increased by 19-26% with stimulation in three subjects, suggesting improved stability and confidence.
3
Subjects consistently rated propulsion with stimulation to be easier for both level surfaces and inclines, indicating a subjective benefit even when objective measures were unchanged.

Research Summary

The study examined the effects of electrical stimulation to the trunk and hip muscles on manual wheelchair propulsion in individuals with spinal cord injury. Results showed that stimulation can improve propulsion mechanics, efficiency, and perceived effort during level ground propulsion for some individuals. The benefits of stimulation were less pronounced during more demanding activities like sprinting and ramp ascent, although subjects still perceived these activities as easier with stimulation.

Practical Implications

Improved Propulsion Efficiency

Electrical stimulation may reduce the physical demands of wheelchair propulsion on level surfaces, potentially decreasing the risk of upper extremity injuries.

Enhanced Trunk Stability

Increased forward trunk lean with stimulation suggests improved trunk stability and confidence, which may lead to better functional reach and activity.

Subjective Benefit

Even when objective measures were unchanged, the perception of reduced effort with stimulation could improve adherence and quality of life for wheelchair users.

Study Limitations

1
The small sample size compromises rigorous exploration of inter-subject differences
2
Sprints and ramps were difficult and fatiguing for some subjects, which limited the number of repetitions possible.
3
There is potential for selection bias since inclusion was not randomized

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