Effects of injury proneness and task difficulty on joint kinetic variability

Med Sci Sports Exerc. 2000 Nov;32(11):1833-44. doi: 10.1097/00005768-200011000-00004.


Purpose: The purpose was to investigate the effects of lower extremity overuse injury proneness and landing height on the variability of selected joint moment characteristics.

Methods: Ten subjects from each of two groups (healthy and injury prone) performed 10 landings from a platform (heights: 50, 100, and 200% of maximum vertical jump). Force platform (1000 Hz) and video (200 Hz) information were collected and used to compute ankle, knee, and hip joint moment values during impact (0-100 ms post contact). Moment peak, time to peak, and impulse values were used to determine variability across 10 trials for each subject and height. MANOVAs and univariate follow-up tests were used to assess variability differences between groups and among heights.

Results: Results revealed ankle moment variability differences (P < or = 0.05; Tukey) between groups for peak and time to peak variables at the 100% and 50% heights, respectively. The injury-prone group exhibited greater variability for the peak variable, whereas the healthy group showed greater variability for the temporal variable. Groups also differed on the impulse variables (P < or = 0.02; MANOVA), but follow-up tests failed to determine specific joints or directions of differences. Both groups exhibited tendencies for greater variability (P < or = 0.05; Tukey) with increases in height up to 100% MVJ and decreases in variability with further height increases.

Conclusions: Results suggest that groups differed in joint moment variability, possibly indicating a relationship between variability and overuse injuries, although the variables and directions of differences were inconsistent. For some variables, variability increased and then decreased with height increases for both groups, suggesting a range of heights within which the neuromuscular system adapted.

MeSH terms

  • Adult
  • Ankle Joint / physiology*
  • Female
  • Hip Joint / physiology*
  • Humans
  • Kinetics
  • Knee Joint / physiology*
  • Male
  • Movement
  • Video Recording
  • Wounds and Injuries / etiology*