Acute remote ischemic preconditioning has no effect on quadriceps muscle endurance

We previously reported that the beneficial effects of ischemic preconditioning (IPC) on whole-body and local exercise performances may be due to enhanced skeletal muscle function, such as improved O2 availability. We and others also demonstrated that remote IPC (RIPC) enhanced whole-body exercise performance. Nevertheless, our previous study indicated that the beneficial effects of RIPC on whole-body exercise performance may not involve enhanced skeletal muscle function. To clarify this issue, the present study examined the effects of RIPC on quadriceps muscle endurance and deoxygenation dynamics during local knee extensor exercise. Fourteen men performed a sustained isometric unilateral knee extensor exercise at 20% of maximal voluntary contraction until task failure. Prior to the exercise, the subjects underwent RIPC (3 × 5 minutes non-exercising leg occlusion) or control (CON; no occlusion) treatment. During the exercise, near-infrared spectroscopy-derived deoxygenation dynamics in the quadriceps vastus lateralis muscle were continuously recorded. The endurance time to task failure did not differ significantly between RIPC and CON conditions. Furthermore, the quadriceps muscle deoxygenation dynamics during exercise did not differ significantly between the two conditions. These findings suggest that RIPC may not enhance muscle endurance, which corresponded with the ineffectiveness of RIPC on skeletal muscle function during local exercise.