Phys. Ther. Korea 2020; 27(2): 155-161
Published online May 20, 2020
© Korean Research Society of Physical Therapy
1Department of Physical Therapy, Chapman University, Irvine, CA, USA, 2Injury Prevention and Biomechanics Laboratory, Department of
Physical Therapy, Yonsei University, Wonju, Korea
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0)which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Background: The consequences of falls are often debilitating, and prevention is important. In theory, the lower the center of mass (COM), the greater postural stability during standing, and a weight belt at the waist level may help to lower the COM and improve the standing balance.
Objects: We examined how the limit of stability (LOS) was affected by the lowered center of mass with the weight belt.
Methods: Twenty healthy individuals participated in the LOS test. After calculating each participant’s COM, a weight belt was fastened ten centimeters below the COM. Trials were acquired with five weight belt conditions: 0%, 2%, 4%, 6%, and 8% of body weight. Outcome measures included reaction time, movement velocity, endpoint excursion, maximum excursion, and directional control in 4 cardinal moving directions.
Results: None of our outcome variables were associated with a weight belt (p > 0.075), but all of them were associated with moving direction (p < 0.01). On average, movement velocity of the COM and maximum excursion were 31% and 18% greater, respectively, in mediolateral than anteroposterior direction (5.4°/s vs. 4.1°/s; 97.5% vs. 82.6%).
Conclusion: Our results suggest that postural stability was not affected by the weightinduced lowered COM, informing the development and improvement of balance training strategies.
Keywords: Balance, Center of mass, Limit of stability, Weight belt