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Eighteen young (23 ± 4 yr) and 25 older (70 ± 4 yr) male sprinters were examined for ground reaction force (GRF) and temporal-spatial variables. The data were collected during maximum-speed phase, and variability and symmetry indices were calculated from a total of 8 steps. There was little variation (CV < 6%) in vertical and resultant GRF and kinematic variables, while impact loading had high variability (CV: 10–21%). Overall, the pattern of variability was similar in both groups. Yet, a small but significant age-related increase in CV was evident in horizontal GRFs. There was a variable-specific asymmetry between legs but it was not related to leg dominance. No age differences existed in the symmetry indices. Results indicate that only selected force platform variables are symmetric and repeatable enough so that their use for comparison purposes is appropriate. Data also suggest that aging may increase variability in certain biomechanical measures, whereas symmetry is not affected by age.
Marko T. Korhonen (Corresponding Author) is with the Department of Health Sciences, University of Jyväskylä, Jyväskylä, Finland. Harri Suominen is with the Department of Health Sciences, University of Jyväskylä, Jyväskylä, Finland. Jukka T. Viitasalo is with KIHU—Research Institute for Olympic Sports, Jyväskylä, Finland. Tuomas Liikavainio is with the Department of Physical and Rehabilitation Medicine, Kuopio University Hospital, Kuopio, Finland. Markku Alen is with the Department of Medical Rehabilitation, Oulu University Hospital and Institute of Health Sciences, University of Oulu, Oulu, Finland. Antti A. Mero is with the Department of Biology of Physical Activity, University of Jyväskylä, Jyväskylä, Finland.