Remote Ischemic Preconditioning Effects On Muscular Strength And Endurance In Young Adults

PURPOSE: Remote ischemic preconditioning (RIPC) is an intervention where brief periods of 3 or 4 cycles of 5 minutes of blood flow blockage with an occlusion pressure of 200-220 mmHg is followed by 5 minutes of reperfusion. This intervention has been used in clinical settings to reduce ischemic reperfusion injury and to improve cardiovascular functions. Since RIPC stimulates growth factors, it may also improve skeletal muscle strength and endurance. However, studies have yet to conclude whether RIPC training could be effective in facilitating muscular strength and endurance improvements. Thus the purpose of this study is to test to the extended to which four weeks of RIPC intervention improves lower limb muscular strength and endurance in healthy young adults. METHODS: 8 healthy young participants without cardiovascular disease risk factors were recruited from the local community (n = 8; 2 M, 6 F, 21.2 ± 0.8 yr.; BMI 23.6 ± 3.3 kg/m2). RIPC training has applied for 4 weeks in the sequence of 6 days of training with a 1-day break (total 24 days) using 4 cycles of 5 minutes occlusion with 200 mmHg pressure followed by 5 minutes of reperfusion RIPC protocol. Lower limb strength and endurance were assessed by isometric (90° knee angle) and isokinetic knee extension (180° per second) movements using Biodex System 4. Paired t-tests were used to analyze the data. RESULTS: Current data analysis showed that 4 weeks of repeated RIPC intervention significantly improved total work (-198 ± 492.4 vs.-444 ± 525.2, p < 0.5 )and average IKPKTQ (-6.4 ± 14.4 vs. -11.76 ± 15.61 Nm, p = 0.05) while isokinetic peak torque (IKPKTQ) (-0.8 ± 12.41 vs. -6.8 ± 16.5 Nm, p = 0.07) and ∆average power (1.7 ± 33.7 vs. 23.43 ± 30.43v W, p = 0.06) tended to improve. However, no significant changes were seen in isometric peak torque (base vs. 4 weeks: 152 ± 81.6 vs. 157.8 ± 79.4 Nm, p = 0.16) in addition to in addition to ∆work fatigue (18.9 ± 11.5 vs. 11.1 ± 16.1%, p = 0.26). CONCLUSION: Current preliminary data showed that 4 weeks of RIPC intervention improved muscular strength and limited muscular endurance improvement. These outcomes suggest that repeated RIPC could be an intervention to improve muscular strength and endurance. Further research is needed to elucidate physiological mechanisms to explain these outcomes.