Effects of 4weeks of low-load unilateral resistance training, with and without blood flow restriction, on strength, thickness, V wave, and H reflex of the soleus muscle in men.

Abstract

To test the effects of 4weeks of unilateral low-load resistance training (LLRT), with and without blood flow restriction (BFR), on maximal voluntary contraction (MVC), muscle thickness, volitional wave (V wave), and Hoffmann reflex (H reflex) of the soleus muscle. Twenty-two males were randomly distributed into three groups: a control group (CTR; n=8); a low-load blood flow restriction resistance training group (BFR-LLRT; n=7), who were an inflatable cuff to occlude blood flow; and a low-load resistance training group without blood flow restriction (LLRT; n=7). The training consisted of four sets of unilateral isometric LLRT (25% of MVC) three times a week over 4weeks. MVC increased 33% (P<0.001) and 22% (P<0.01) in the trained leg of both BFR-LLRT and LLRT groups, respectively. The soleus thickness increased 9.5% (P<0.001) and 6.5% (P<0.01) in the trained leg of both BFR-LLRT and LLRT groups, respectively. However, neither MVC nor thickness changed in either of the legs tested in the CTR group (MVC -1 and -5%, and muscle thickness 1.9 and 1.2%, for the control and trained leg, respectively). Moreover, V wave and H reflex did not change significantly in all the groups studied (Vwave/M wave ratio -7.9 and -2.6%, and H max/M max ratio -3.8 and -4%, for the control and trained leg, respectively). Collectively, the present data suggest that in spite of the changes occurring in soleus strength and thickness, 4weeks of low-load resistance training, with or without BFR, does not cause any change in neural drive or motoneuronal excitability.