Ischemic preconditioning increases muscle perfusion, oxygen uptake, and force in strength-trained athletes

Abstract

Muscle ischemia and reperfusion induced by ischemic preconditioning (IPC) can improve performance in various activities. However, the underlying mechanisms are still poorly understood. The purpose of this study was to examine the effects of IPC on muscle hemodynamics and oxygen (O2) uptake during repeated maximal contractions. In a cross-over, randomized, single-blind study, 10 strength-trained men performed 5 sets of 5 maximal voluntary knee extensions of the right leg on an isokinetic dynamometer, preceded by either IPC of the right lower limb (3×5-min compression/5-min reperfusion cycles at 200 mm Hg) or sham (20 mm Hg). Changes in deoxyhemoglobin, expressed as a percentage of arterial occlusion, and total hemoglobin ([THb]) concentrations of the vastus lateralis muscle were monitored continuously by near-infrared spectroscopy. Differences between IPC and sham were analyzed using Cohen's effect size (ES) ± 90% confidence limits, and magnitude-based inferences. Compared with sham, IPC likely increased muscle blood volume at rest (↑[THb], 46.5%; ES, 0.56; 90% confidence limits for ES, -0.21, 1.32). During exercise, peak force was almost certainly higher (11.8%; ES, 0.37; 0.27, 0.47), average force was very likely higher (12.6%; ES, 0.47; 0.29, 0.66), and average muscle O2 uptake was possibly increased (15.8%; ES, 0.36; -0.07, 0.79) after IPC. In the recovery periods between contractions, IPC also increased blood volume after sets 1 (23.6%; ES, 0.30; -0.05, 0.65) and 5 (25.1%; ES, 0.32; 0.09, 0.55). Three cycles of IPC immediately increased muscle perfusion and O2 uptake, conducive to higher repeated force capacity in strength-trained athletes. This maneuver therefore appears relevant to enhancing exercise training stimulus.

Sex-Specific Impact of Ischemic Preconditioning on Tissue Oxygenation and Maximal Concentric Force

“…The present data demonstrated clear differences between sexes; compared with males, females exhibited a lower force decrement over the five sets of maximal, isokinetic contractions. The lack of change in males is in keeping with previous studies reporting no differences between SHAM and IPC conditions in the measured fatigue index, despite higher peak and mean power outputs during the first repetitions of a series of ten 6 s cycle sprints (Patterson et al, 2015), or higher average force during maximal voluntary knee extensions after IPC (Paradis-Deschenes et al, 2016). This apparent sex difference in response to IPC could be attributed in part to the fact that males increased their initial and total force leading to greater subsequent metabolic and ionic perturbations (Balsom et al, 1994; Glaister, 2005).…”

“…Interestingly, extraneous infusion of adenosine, which is a key acting molecule released during IPC, preferentially enhances vasodilation of arterioles to type II fibers (Wunsch et al, 2000). Therefore, due to the greater O 2 extraction of type II fibers when highly perfused (Wilson et al, 1977), it has been suggested that these fibers might benefit more from an increase in blood perfusion than the more aerobic type I fibers (Faiss et al, 2013; Paradis-Deschenes et al, 2016), which could explain the higher Δ[HHb] avg in strength-trained males in the present study.…”

“…This technique promotes local vasodilation, improves O 2 delivery (Enko et al, 2011; Bailey et al, 2012a), and enhances the efficiency of muscular contraction (Pang et al, 1995; Moses et al, 2005). Higher muscle O 2 utilization was also demonstrated in the quadriceps of strength-trained male athletes after performing IPC compared to placebo compressions (Paradis-Deschenes et al, 2016). It is not surprising, therefore, to observe that IPC can improve maximal physical performance in various exercise modes in male participants (De Groot et al, 2010; Bailey et al, 2012a; Paradis-Deschenes et al, 2016), although this is not a universal finding (Incognito et al, 2015).…”

“…Higher muscle O 2 utilization was also demonstrated in the quadriceps of strength-trained male athletes after performing IPC compared to placebo compressions (Paradis-Deschenes et al, 2016). It is not surprising, therefore, to observe that IPC can improve maximal physical performance in various exercise modes in male participants (De Groot et al, 2010; Bailey et al, 2012a; Paradis-Deschenes et al, 2016), although this is not a universal finding (Incognito et al, 2015). Before exercise sport performance applications, IPC was originally studied for its potential clinical relevance, and in this context, it is interesting to note that females appeared to display smaller clinical benefits compared with their male counterparts.…”

The effect of ischaemic preconditioning on central and peripheral fatiguing mechanisms in humans following sustained maximal isometric exercise

“…Early findings suggested enhanced oxygen delivery to be the primary mechanistic change induced by IPC; however, recent research has proposed that IPC might also affect neural drive to working skeletal muscle (Barbosa et al., ; Crisafulli et al., ; Cruz, de Aguiar, Turnes, Salvador, & Caputo, ; Cruz, Pereira, Lisboa, & Caputo, ; Paradis‐Deschênes et al., ; Tanaka et al ., ). Barbosa et al.…”