Intro: Maximizing physiological adaptations is the key for optimal performance. Ischemic preconditioning is well-known to improve acute exercise capacity and performance. Aims/Objectives: The purpose of this study was to examine whether endurance training with ischemic preconditioning would enhance work of training and thus fortify physiological adaptations and increase performance.
Methods: Sixteen male distance runners (age: 34.1±5.1 yrs, weight: 70.8±4.1 kg) participated in the study. Training consisted of 2 high-intensity interval sessions (90-100% VO2max) and 3 continuous sessions (70-80% VO2max) per week for 2 months. Participants were divided into two groups of equal fitness level. Before interval training the ischemic preconditioning group (ISC, n=8) underwent 5 min total blood flow occlusion of each leg separately 3 times per session with pressure cuffs (250mmHg), while the control group (CON, n=8) underwent the same protocol but without pressure being applied. Pre and post training measurements of VO2max, hematological and cardiovascular variables were performed, while a field-specific test of 5x1000m with 2 minutes recovery was executed.
Results: Weekly running volume was similar between groups (ISC: 80.2±3 km vs CON: 80.6±4 km). ISC acheived faster (p<0.05) interval training average speed (18±0.4 km/h) than CON (17.4±0.3 km/h). Training increased VO2max (p<0.01) in both groups (ISC: 55.3±1.2 vs 60.1±1.8 ml/kg/min, CON: 55±2 vs 57.6±1.9 ml/kg/min) but the increase was higher in ISC (training x group interaction: p<0,05). Maximal aerobic speed (vVO2max) was also increased in both groups (p<0.01) (ISC: 18.4±0.9 vs 19.6±0.9 km/h, CON:18.2±0.7 vs 18.9±0.6 km/h) with a higher increase in ISC (training x group interaction: p<0.05). Post training running times during the 5x1000m test were faster in ISC than CON (p<0.05). ISC compared to CON showed a more pronounced increase in blood volume (5415±438 vs. 5103±517 ml) and plasma volume (3114±271 vs 2912±246 ml) (training x group interaction: p<0.05). Moreover, there was a training effect (p<0.05) on cardiac output, stroke volume, mass of hemoglobin and red cell volume without differences between groups.
Conclusions: Muscular ischemic preconditiong applied prior to a regular training mode may enhance physiological adaptations mainly through hematological alterations and, thus, improve athletic performance.
Ethical standards: The study was approved by the University’s Ethical Committee for human experimentation and conformed to the Declaration of Helsinki.