# Effects of Different Body Postures on Handgrip Strength Measurements Among Young Adults: A Preliminary Comparison of Standing, Chair-Seated, and Wheelchair-Seated Positions

## TL;DR

This study compares handgrip strength measurements in young adults across three postures and finds that posture affects the results.

## Contribution

The study introduces the first comparison of handgrip strength in a wheelchair-seated position alongside standing and chair-seated positions.

## Key findings

- Handgrip strength was significantly lower in the wheelchair-seated position compared to the standing position.
- Standardizing posture during handgrip testing is crucial for accurate longitudinal evaluations and intervention assessments.

## Abstract

Introduction: Although the influence of posture on handgrip strength measurement has been previously reported, no study has examined the wheelchair-seated position. This study aimed to compare handgrip strength values between the standing, chair-seated, and wheelchair-seated positions.

Materials and methods: This prospective observational study was conducted between May and June 2025 and included 29 university medical students from the International University of Health and Welfare in Otawara, Japan. Handgrip strength was measured under three conditions, i.e., standing, chair-seated, and wheelchair-seated, at one-week intervals. Statistical analyses were performed using one-way repeated-measures analysis of variance with Bonferroni post hoc comparisons.

Results: Handgrip strength values were 36.2 ± 10.2 kg in the standing position, 35.0 ± 10.0 kg in the chair-seated position, and 34.1 ± 9.6 kg in the wheelchair-seated position, showing a descending order from standing to chair-seated to wheelchair-seated. The handgrip strength in the wheelchair-seated position was significantly lower than that in the standing position. When the standing position was defined as 100%, the relative values were 97.0 ± 8.3% for chair-seated and 94.8 ± 8.0% for wheelchair-seated, with the handgrip in the wheelchair-seated significantly lower than that in the standing position.

Conclusions: Handgrip strength was influenced by body posture during measurement. To ensure accurate evaluation of longitudinal changes and intervention effects in the same individual, it is important to standardize the postural conditions during handgrip strength testing.