Biomechanical Implications of Training Volume and Intensity in Aging Runners.

Running speed is slower in middle-aged compared to younger runners due to reduced ankle but not hip and knee kinetic output. Running-specific training helps attenuate age-related declines in measures of endurance, muscle strength and gait speed. Considering the adaptability of the human body in response to imposed stresses, maintaining training volume and intensity may play a role in modifying running biomechanics in middle-aged runners. The purpose of this study was to compare running biomechanics between young and middle-aged runners when controlling for the confounding effects of training volume and intensity.

15 middle-aged runners, 15 young runners with similar training volume as the middle-aged group and, 15 young runners with similar preferred training paces (i.e. intensity) as the middle-aged runners participated in the study. Lower limb joint kinetics were calculated from kinematic and ground reaction force data during over-ground running at a submaximal speed and compared among groups.

Middle-aged runners ran with similar peak ankle power compared to volume-matched younger runners although peak plantarflexor moment was 10.5% lower in the middle aged group (p = 0.046; Cohen’s d = 0.78). Middle-aged runners ran with similar ankle plantarflexor moment and joint power compared to training pace-matched young runners. As expected, no age-related differences were observed in hip and knee kinetics when training volume or pace were matched between age groups. These results suggest that training pace may be more effective in attenuating age-related declines in plantarflexor kinetics in middle-aged runners.

From these findings, we propose the hypothesis that both training volume and training pace may play a role in maintaining plantarflexor kinetics but that training pace may have a greater impact on ankle plantarflexor kinetics in middle-aged runners.