Does arm swing emphasized deliberately increase the trunk stability during walking in the elderly adults?

The purpose of this study was to determine whether trunk stability while walking changes when arm swing is deliberately altered in elderly individuals. Participants included 21 community-dwelling elderly individuals (7 men and 14 women; age, 81.8 ± 5.0 years). We measured trunk acceleration by using a wireless miniature sensor unit containing a tri-axial linear accelerometer under 3 walking conditions: normal walking (normal condition), deliberately walking without any arm swing (no swing condition), and walking with a deliberately emphasized arm swing (over swing condition). To evaluate trunk stability during walking, we calculated harmonic ratios (HRs) based on trunk tri-axial acceleration signals (anteroposterior: AP, vertical: VT, and mediolateral: ML). HR-AP and HR-VT were not significantly different across the 3 conditions, but HR-ML in the over swing condition was significantly higher than that in the other 2 conditions by generalized estimating equations (GEE) adjusted for walking speed (p<0.05). These findings indicate that trunk stability in the ML direction increased when the elderly individuals walked with a deliberately emphasized arm swing.