1 Universidade de São Paulo, São Paulo, Brazil
Introduction: Type I diabetes show decreased motor performance due to the loss of skeletal muscle and strength. Resistance training (RT) is a strategy recommended to increase muscle size and their function and, in addition to leucine (LEU), is known as a key regulator of muscle protein synthesis. Therefore, the aim of this study was to examine whether LEU supplementation improves motor performance in diabetic rats. Methods: 5-day old male rats received streptozotocin (120 mg/kg). After 21 days, the animals were randomly divided into 4 groups: D: diabetic; DT: diabetic submitted to RT; DL: diabetic fed 5% of LEU supplemented diet; DLT: diabetic, LEU and RT. A functional test (grip strength, length and width between two footprints) was performed on week 11. The maximum score of grip strength was measured by grip meter and for ambulation test in a corridor (length: 90 cm; width: 11 cm) and the mean length and width of steps were determined by measurement of their ink footprints. Results: After 8 weeks, there was no difference in strength, in length and in width of footprints between D and DL. However, DLT (14.29N) and DT (14.01N) groups improved strength compared to their non-trained groups DL (10.29N) and D (9.10N). The ambulation results showed that the length between two footprints in DLT (14.43 cm) and DT (13.91 cm) groups was higher when compared to D (12.13 cm) group; and the width of footprints of DLT (2.94 cm) and DT (2.69 cm) groups was superior to their non-trained groups DL (2.31 cm) and D (2.04 cm). Conclusion: The LEU supplementation alone did not further increase muscle strength, length and width between two footprints in diabetic rats. The stimulus of RT was probably responsible for favorable adaptive responses observed in both experimental groups trained, leading to improved motor performance.