The relationship among gait characteristics between younger and older adults

The relationship between the center of pressure (COP) and the center of gravity (COG) has been studied in both static and dynamic conditions. The understanding of the relationship between these two variables is particularly important in the elderly during ambulation. This study compared the step length/max leg length ratio, dual support/single support ratio, GRF/weight ratio, joint ratios between the hip, knee and ankle and distance between the COP and COG during heel strike, loading, mid stance, initial dual stance and toe off between healthy older and younger adults. Group I consisted of older men (n = 4) (mean age 75.2 years; height = 169.93 cm; weight = 76.6 kg) and women (n = 11) (mean age 72.6 years; height = 163.07 cm; weight = 71.7 kg). Group II consisted of younger, college age men (n = 4) (mean age 21.6 years; height = 182.88 cm; weight = 98.8 kg) and women (n = 7) (mean age 21.3 years; height = 169.67 cm; weight = 67.2 kg). All of the volunteer participants were rear foot strikers with no history of falling and free of any pathology that would adversely affect their gait. Force and (2D) video data of 5 trials per subject were collected at a walking speed of their choice. Motion analysis software was used to generate the necessary kinetic and kinematic variables. Each variable's 5-trial mean value was entered into a 2 way, repeated measures ANOVA. Results indicated significant differences across gait stage in step length/max leg length ratio, dual support/single support ratio, GRF/weight ratio, the knee/hip, ankle/hip ratios and the distance between the COP and COG. A significant group by stage interaction was identified for COG - COP distance. No other significant differences were found.; The results indicate that the elderly had a narrower COG - COP width and walked more upright during dual stance and toe off. Gait velocity was not a dependent variable in this study. However, gait speed was self imposed and there was no significant difference between the two groups. Slower gait speed is highly correlated to other kinematic adaptations in elderly with problematic dynamic balance. This suggests that healthy, physically active elderly do not demonstrate the same degradation in balance during gait than less healthy, inactive elderly.