Effect of seat height on manual wheelchair foot propulsion, a repeated-measures crossover study: part 2 – wheeling backward on a soft surface

Abstract

Purpose

The aim of this study was to test the hypotheses that, during manual-wheelchair foot propulsion backward on a soft surface, lowering the seat height increases speed, push frequency and push effectiveness, and decreases perceived difficulty.

Materials and methods

In a repeated-measures crossover study, 50 able-bodied participants used one foot to propel a manual wheelchair 5 m backward on a soft surface at 5 seat heights, ranging from 5.08 cm below to about 5.08 cm above lower-leg length, in random order. We recorded Wheelchair Skills Test (WST) capacity scores and used the Wheelchair Propulsion Test (WPT) to calculate speed (m/s), push frequency (cycles/s) and push effectiveness (m/cycle). We also recorded the participants’ perceived difficulty (0–4) and video-recorded each trial.

Results

WST capacity scores were reduced at the higher seat heights. Using repeated-measures models (adjusted for age, sex and order), there were negative relationships between seat height and speed (p < 0.0001) and push effectiveness (p < 0.0001). Lowering the seat height by 5.08 cm below lower-leg length corresponded to improvements in speed of 0.097 m/s and in push effectiveness of 0.101 m/cycle. The trend for push frequency was also significant (p = 0.035) but the effect size was smaller. Perceived difficulty increased with seat height (p < 0.0001). The video-recordings provided qualitative kinematic data regarding the seated “gait cycles”.

Conclusions

During manual-wheelchair foot propulsion backward on a soft surface, lowering the seat height increases speed and push effectiveness, and decreases perceived difficulty.

IMPLICATIONS FOR REHABILITATION

• Backward wheelchair foot propulsion on soft surfaces is affected by seat height.

• Speed (m/s) is improved if the seat height is lowered.

• Push effectiveness (m/gait cycle) is improved if the seat height is lowered.

• Perceived difficulty of propulsion is lower if the seat height is lowered.

Keywords:

• (MESH) rehabilitation
• wheelchair
• foot
• motor skills
• stroke

Acknowledgements

The authors thank Katie McLean BA LIT MLIS AHIP, and David Barteaux BA, LT for their assistance in the literature search, Kim Parker MEng for her assistance in managing the video data, and Marwan Abouelela, MD, MHI, Maddie Sherman, MScOT, Victoria Haworth, MScOT and Lu Han, MScOT for their assistance in data collection.

Geolocation information

This study was conducted in Halifax, Nova Scotia, Canada (gps coordinates 44° 39′ 3.8520″ N and 63° 34′ 57.6732″ W).

Disclosure statement

No potential conflict of interest was reported by the author(s).