Muscle strain is a common injury with a high recurrence rate. Due to the heterogeneity of strain injuries, experimental animals provide controlled and reproducible models to investigate such injuries. Sciatic Function Index (SFI) is a clinically feasible method to assess hind limb recovery in rodents after induced injuries. Objectives: To investigate time to recovery of SFI after induced-strain in tibialis anterior (TA) muscle in rats. Methods: Sixteen adult male Wister rats were randomly and

more »

... ually divided to a normal control group that received no intervention, and TA induced muscle strain group. Muscle strain was induced using an external weight that corresponded to 150% of the animal body weight. SFI was tested only once in the control group. For the muscle strain group, SFI was tested on the 1 st , 2 nd , 3 rd , 4 th , 7 th , 11 th , 20 th and 24 th days after strain induction. Results: Comparisons between group showed significant difference in SFI on the 1 st , 2 nd , 3 rd and 4 th days (p= 0.012, 0.012, 0.012 and 0.028, respectively). Conclusions: In a rat animal model of TA induced muscle strain, functional recovery measured by SFI is evident on the 7 th day post-injury, which corresponds to the sub-acute phase of injury. Level of evidence: V. KEY WORDS: sciatic function index, muscle strain, functional recovery, rats.