Effect of isometric exercise with different load with and without blood flow restriction on fast twitch fibers recruitment

Recruitment of fast twitch muscles cause an increase in muscle mass and strength but these muscles are recruited in high intensities. Old people or persons in rehabilitation process couldn’t do intense training. On the other hand, it has been told that training with blood flow restriction could recruit fast twitch muscles in low intensity. Therefore, we decided to investigate the acute effect of isometric exercise with different load with and without blood flow restriction on fast twitch fibers engagement.
10 male college students participated in this clinical cross over trail. The study protocol was consisted of six 10-second isometric contractions, and between every two sets participants had 60 seconds of rest. Lactate concentrations were measured before, immediately after and 10 min later. IEMG index was recorded during every exercise session.
Lactate concentrations and IEMG were significantly different between exercise with 65% MVC with and without blood flow restriction and these indexes was higher in exercise with 65% MVC with blood flow restriction. Lactate concentrations and IEMG were similar in exercise with 65% MVC with blood flow restriction and 100% MVC without blood flow restriction.
It seems that in same intensity isometric exercise with blood flow restriction can cause more engagement of fast twitch fiber than exercise without blood flow restriction and engagement of fast twitch muscle in exercise with 65% MVC with blood flow restriction was same compared with exercise with 100% MVC without blood flow restriction.