Analysis of Neuromuscular Control in Young and Older Individuals During Lateral Stepping

Older adults can develop neuromuscular deficiencies. We tested the hypothesis that these deficiencies could be reflected in altered neuromuscular control during normal daily tasks. Hence, we compared the ability to modulate ground reaction force (GRF) during lateral stepping (LS) from different step heights between younger and older adults. Kinetic data was obtained from younger (23-33 yrs, n=5) and older (57-65 yrs, n=5) male and female subjects. They stood on top of two 4-inch/8-inch high platforms. Each platform was placed on separate force plates. The subjects were instructed to step down laterally using their non-dominant leg and then step up to the original position. GRF and joint-angle kinematics of both limbs were recorded for the two-step heights. The time (% total) to achieve maximum amount of force (as % body weight) exerted was calculated using data from the average of three LS trials per subject. It was significantly different between males (32.75±1.57) and females (35.75±1.28) (p=0.012) or between young (33.479±1.43) and old (35.021±1.43) (p=0.018) using a three way repeated measures ANOVA comparing step height (4 inch, 8 inch), gender (male, female), and age (young, old.) According to the data, neuromuscular control of the LS task is affected by age and gender.