A Comparison Of Lower Extremity Joint Kinetics During Walking Between Runners And Inactive Individuals.

Abstract

Age-related changes affecting gait can begin as early as the third decade. Running requires greater plantarflexor involvement than walking, suggesting that running may provide a large enough benefit in retaining the plantar flexor function. In doing so, running may reduce or postpone the distal-to-proximal shift in joint kinetics that has been observed in aging individuals. PURPOSE The purpose of this study was to investigate walking mechanics and the presence of age-related gait adaptations in runners between the ages of 36-45 years old compared to inactive individuals of the same age. METHODS A total of 30 individuals aged 36-45 years old were included in this analysis (Table 1). Participants walked at a self-selected pace over a 17-m long runway with force platforms collecting kinetic data. Six successful walking trials were selected for analysis. Between-group differences were determined using independent t-tests and effect sizes. RESULTS Mean values for kinetic variables of interest are shown in Table 2. When normalized to body mass (BM), runners generated greater knee power than inactive individuals (p = 0.01). When normalized to fat-free mass (FFM), inactive individuals had a greater peak plantarflexor moment than runners (p = 0.01). CONCLUSION Knee power was no longer greater in runners than inactive individuals when normalized to FFM, suggesting this difference is a function of overall mass. However, when normalized to FFM, the greater plantarflexor torque exhibited by inactive individuals suggests their need to generate a greater relative torque than the runners to assist in propelling them forward. FUNDING: This research was co-funded by European union and Ministry of Education, Youth and Sports of the Czech Republic, grant number CZ.02.1.01/0.0/0.0/16_019/0000798 Program 4 Healthy Aging in Industrial Environment.