Background: lower-limb stress fracture is one of the most common types of running injuries. There have been several studies focusing on the association between stress fractures and biomechanical factors. In the current study, the ground reaction force and loading rate are examined. There is disagreement in the literature about whether the history of stress fractures is associated with ground reaction forces (either higher or lower than control), or with loading rates.
Methods: a systematic review of the literature was conducted on the relationship between the history of tibial and/or metatarsal stress fracture and the magnitude of the ground reaction force and loading rate. Fixed-effect meta-analysis techniques were applied to determine whether or not the ground reaction force and/or loading rate are different between the stress fracture and control groups.
Findings: thirteen articles were identified through a systematic search of the literature. About 54% of these articles reported significantly different vertical ground reaction force and/or loading rate between the stress fracture and control groups. Other studies (~46%) did not observe any significant difference between the two groups. Meta-analysis results showed no significant differences between the ground reaction force of the lower-limb stress fracture and control groups (P>0.05). However, significant differences were observed for the average and instantaneous vertical loading rates (P<0.05).
Interpretation: the currently available data does not support the hypothesis that there is a significant difference between the ground reaction force of subjects experiencing lower-limb stress fracture and control groups. Instead, the vertical loading rate was found to be significantly different between the two groups.
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