Low-volume strength and endurance training prevent the decrease in exercise hyperemia induced by non-dominant forearm immobilization

We examined the effect of 3-week upper limb immobilization on conduit artery cross-sectional area and peak hyperemia (BFpeak) after exhaustive dynamic handgrip exercise (Exdyn), and that of low-volume strength and endurance training during immobilization. Healthy volunteers (n = 21; mean age, 22 years) were divided into 3 groups: immobilization only (IMM; n = 7), immobilization with training (STR + END; n = 7), and control (no immobilization or training, CNT; n = 7). Endurance training comprised Exdyn at 30% maximum voluntary contraction (MVC) (duration of each session, ~60 s; twice weekly). Strength training involved intermittent isometric handgrip exercise at 70% MVC (duration of each session, 40 s; twice weekly), repeated 10 times. We used ultrasound methods to measure the brachial artery cross-sectional area and the BFpeak after Exdyn for 5 min pre- and post-immobilization. We found a significant group by time interaction in BFpeak (p < 0.05). A significant decrease was found in BFpeak in the IMM (p < 0.05) between pre- and post-immobilization and a protective effect in the STR + END. The 3-week upper limb immobilization did not influence the baseline artery cross-sectional area. In conclusion, BFpeak decreased after 3-week upper limb immobilization and a combination of strength training and endurance training preserved the blunted BFpeak.