Muscle Ischemic Preconditioning does not Improve Performance during Self-Paced Exercise

Abstract

Muscle ischemic preconditioning (IP) has been found to improve exercise performance in laboratory tests. This investigation aims at verifying whether performance is improved by IP during self-paced exercise (SPE) in the field. 11 well-trained male runners performed 3 randomly assigned 5 000 m self-paced running tests on an outdoor track. One was the reference (RT) test, while the others were performed following muscle IP (IPT) and a control sham test (ST). Average speeds were measured during each test. Mean values in oxygen uptake (VO2), aerobic energy cost (AEC) during race and post-race blood lactate (BLa) were gathered. Data showed that none of the studied variables were affected by IPT or ST with respect to the RT test. Average speeds were 4.63±0.31, 4.62±0.31 and 4.60±0.25 m·s(-1) for the RT, the ST and the IPT tests, respectively. Moreover, there was no difference among tests in speed reached during each lap. VO2 was 3.5±0.69, 3.74±0.85 and 3.62±1.19 l·min(-1). AEC was 1.04±0.15, 1.08±0.1 and 1.09±0.15 kcal·kg(-1)·km(-1). Finally, post-race BLa levels reached 12.85±3.54, 11.88±4.74 and 12.82±3.6 mmol·l(-1). These findings indicate that performance during SPE is not ameliorated by ischemic preconditioning, thereby indicating that IP is not suitable as an ergogenic aid.

Ischemic preconditioning: Potential impact on exercise performance and underlying mechanisms

“…IPC had no beneficial effects on the mean V ・ O2, V ・ E, and HR during a 5 km running time trial 22) , the submaximal V ・ O2 during maximal incremental leg cycling 13,14) , or during leg cycling at an exercise intensity of 90% V ・ O2peak at the gas exchange threshold 12) . However, IPC decreased LA at the submaximal running speed compared to SHAM 21) .…”

“…Bailey et al (2012a) found that IPC improved 5 km treadmill running time 21) . Meanwhile, Tocco et al (2015) reported that 5000 m selfpaced running test results on an outdoor track were not improved 22) .…”

“…IPC also resulted in increases in HRmax and V ・ Epeak during maximal incremental leg cycling exercise 10) . Because the peak values of blood lactate concentration (LApeak) after exercise may be an indicator of anaerobic capacity, several studies compared the LApeak between IPC and the control (or SHAM), and no effect in LApeak after exercise with IPC was found 4,[9][10][11][12][13][14]18,19,22) . Two studies focused on muscle activity, assessed by electromyography (EMG), between IPC and CON, and no differences in EMG were found during cycle sprints 4) or isometric leg extension 26) .…”

“…As mentioned previously, the results are equivocal. Several studies found an improvement in exercise performance, i.e., time to failure (time trial performance), peak power output, and repetitions, to name a few, after IPC on the primary or a part of the engaged limbs 4,8,[10][11][12][13][18][19][20][21]26) , whereas other studies did not show any beneficial effects [5][6][7]9,10,[14][15][16][17]22,24,25) . A few studies investigated the effects of remote IPC on exercise performance.…”

“…Further, the numbers of ischemic-reperfusion cycles were also varied in previous studies. For example, one study used 2×5 min cycles 8) , nine studies used 3×5 min cycles 5,7,10,[12][13][14]18,23,26) and 13 studies used 4×5 min cycles 4,6,9,11,[15][16][17][19][20][21][22]24,25) . As a result, a manipulation of 2 cycles showed improvement of exercise performance (100%), seven of nine studies using 3 cycles also showed improvement of exercise performance (78%), whereas, only five of 13 studies using 4 cycles showed positive effects with IPC (38%).…”