The effect of incline walking on lower extremity and trunk mechanics in older adults

Older adults are at an increased risk of developing knee osteoarthritis. High internal knee abduction moment during daily activities may elevate the risk of knee osteoarthritis. Incline walking exercise has been found to decrease knee abduction moment in healthy young adults. However, it is unknown if this occurs in healthy older adults. The purpose of this study was to quantify the internal knee abduction moment at different treadmill grades to determine if incline walking could reduce the knee abduction moment in healthy older adults. Twelve healthy older adult males walked on a treadmill at five incline grades (0%, 5%, 10%, 15%, and 20%) at 1.34 ​m⋅s^-1. The primary outcome variable was the internal knee abduction moment. A one-way repeated measures multivariate analysis of variance was performed to determine differences in the dependent variables among incline gradients. Peak knee abduction moment significantly decreased from level walking at all gradients in 10% increments (0%–10%, p ​< ​0.001; 5%–15%, p ​< ​0.002; and 10%–20%, p ​= ​0.04). A reduction in knee abduction moment during incline walking could result in decreased knee joint loading on the medial knee compartment. For older adults, who are looking to exercise to improve their health, incline walking may be beneficial to promote lower body strength and cardiovascular ability without inflicting further harm to the aging knee joints. However, because the frontal plane knee joint was of primary interest in this study, further research is needed to determine the effects of incline walking on other joints and in other planes of motion.