Dynamic balance during running using running-specific prostheses.
Running is beneficial for physical, social, and emotional health, and participating in physical activity, including running, is becoming more popular for people with an amputation. However, this population has a greater risk of falling relative to people without an amputation, which may be a barrier to running. Understanding how dynamic balance is maintained during running is important for removing this barrier. To investigate dynamic balance, we quantified whole-body angular momentum in eight people with a unilateral transtibial amputation (TTA) using running-specific prostheses (RSPs) compared to eight people without TTA during running at 2.5, 3.0, and 3.5 m/s. People with TTA had greater ranges of whole-body angular momentum compared to people without TTA in the frontal and sagittal planes (p < 0.01). These greater ranges resulted from smaller peak medial, lateral, and braking ground reaction forces from the amputated leg compared to the intact leg and people without TTA. Reduced RSP mass relative to the biological leg also influenced whole-body angular momentum as evidenced by smaller ranges of amputated leg angular momentum compared to the intact leg in the frontal and sagittal planes. Smaller amputated leg angular momentum corresponded with smaller contralateral arm angular momentum in the sagittal plane (p < 0.01). People with TTA maintain balance during running with altered muscle coordination and prosthesis characteristics. Restoring mediolateral force generation through prosthetic design advances may help in regulating the frontal plane component of whole-body angular momentum for people with TTA, with potential to improve their ability to maintain balance during running.