Acute effect of hypoxia resulted from BFR, static and dynamic stretch methods in resistance exercise on growth hormone, lactic acid, nitric oxide in resistance trained male
Poster Presentation XML
1Secretary of Physical Education-Department of Education
2University of Guilan, Faculty of Physical Education and Sport Sciences, Rasht, Guilan, IRAN
This study aimed to compare growth hormone, nitric oxide and lactic acid responses during resistance exercise with blood-flow-restriction (BFR) compared with static stretch (SS) and dynamic stretch (DS) in young trained men.
28 healthy men with at least 1 year of regular resistance training prior to the study (mean age 22.28±1.5 years, body mass index of 23.72±1 kg/m2, and body fat percent 12.4±1%) volunteered to participate in this study and were randomly divided into 4 groups including BFR(30% 1RM), SS(75% 1RM), DS, (75% 1RM) and traditional resistance training(75% 1RM). In order to create an isovolumic condition resistance exercises consisted of 4×15 repetitions of knee extension for BFR condition and 4×12 repetitions for others which were implemented unilaterally on subjects' right foot. Intraset intervals were respectively considered 60 and 90 sec for BFR and other three groups. Serum levels of growth hormone, lactic acid and nitric oxide were measured before and immediately after the exercise sessions.

Growth hormone was significantly higher in SS versus other groups (p < 0.001). Despite increasing nitric oxide in post-test of DS and BFR groups, no significant differences were observed between four groups (p < 0.5). Lactic acid was significantly increased immediately after exercise in four training methods (p < 0.001).

This study partly confirms the efficacy and effectiveness of inter-set static and dynamic stretching intervention in resistance exercise as well as blood flow restriction which is confirmed through changes of hormonal and metabolic variables in current study. However, it is not possible to determine which of the conventional methods can be more effective due to the contraversing results in three studied variables.