Abstract Purpose Ιschemic preconditioning is well-accepted to improve exercise capacity and performance. The purpose of this study was to examine whether ischemic preconditioning performed prior to endurance training in a long-term fashion enhances physiological adaptations and performance. Methods Sixteen male distance runners (age: 34.1 ± 5.1 yrs, VO 2 max: 55.0 ± 2.0 ml/kg/min) participated in the study. Training consisted of two high-intensity interval sessions (90–100% VO 2 max) and three continuous sessions (70–80% VO 2 max) per week for eight weeks. Participants were divided into two groups of similar fitness level. Before interval training the ischemic preconditioning group (ISC, n = 8) underwent 3 × 5 min total blood flow occlusion in each leg (applied external pressure using cuffs: 250mmHg), while the control group (CON, n = 8) underwent the same protocol but without pressure being applied. Pre and post training VO 2 max, hematological profile, and blood pessure was evaluated, while a field-specific test of 5 × 1000 m with 2 min break was executed. Results Training increased VO 2 max ( p < 0.01) in both groups (ISC: 3.92 ± 0.1 vs. 4.22 ± 0.1 L/min, CON: 3.94 ± 0.20 vs. 4.05 ± 0.19 L/min) but the increase was higher in ISC (training group x time interaction p = 0.001). Post training average running time during the 5 × 1000 m test was faster in ISC than CON (ISC: 211 ± 3 vs. 200 ± 4 s, CON: 210 ± 4 vs. 205 ± 5 s) (training group x time interaction p = 0.020). Pre versus post values in ISC compared to CON showed a more pronounced increase in blood volume (ISC: 4887 ± 448 vs. 5415 ± 438 ml, CON: 4788 ± 489 vs. 5103 ± 517 ml) (training group x time interaction p = 0.012) and plasma volume (ISC: 2663 ± 309 vs. 3114 ± 271 ml, CON: 2620 ± 306 vs. 2912 ± 246 ml) (training group x time interaction p = 0.009). Moreover, there was a training effect ( p < 0.05) for hemoglobin mass and red cell volume without differences between groups. Conclusions The intervention of ischemic preconditioning prior to interval training may enhance physiological adaptations mainly through hematological alterations and, thus, improve athletic performance.
Loukas et al. (Fri,) studied this question.