Objective:
To analyze the relationship between vertical ground reaction force and knee angular velocity of young and elderly persons during stair descent.
Methods:
The sample consisted of two groups: the Elderly Group (EG; n=10) and the Young Group (YG; n=16). A ladder test consisting of seven steps, with a force plate coupled to the fourth step to acquire kinetic data and determine the moment of foot contact with the step, was used, as well as a system of three-dimensional kinematics with four infrared cameras. The volunteers descended the stairs continuously, at a self-selected speed and pace. The Student's t-test was used for independent samples and the Pearson correlation test was used to test the correlation of the variables, with a level of significance of α=0.05.
Results:
The results showed a significant difference between the YG group (240.7±10.5 g/s) and the EG group (186.4±13.2 g/s) for mean peak knee angular velocity. Regarding peak vertical force (Fz), YG had a higher magnitude of force (1.39±0.03) than EG (1.15±0.02), with a significant difference between the groups (p=0.00). The results also showed a positive correlation between variables (r=0.4).
Conclusion:
The results indicate that elderly persons have a lower knee angular velocity and lower vertical force during stair descent than young people and that there was a correlation between the variables.
Biomechanical Phenomena; Kinetics; Aging