Effects of short‐term detraining following blood flow restricted low‐intensity training on muscle size and strength

Summary We investigated the effects of 3 weeks of detraining on muscle cross‐sectional area ( CSA ) and one‐repetition maximum strength (1‐ RM ) in young men who had previously participated in 6 weeks (3 days week −1 ) of bench press training [blood flow restricted low‐intensity ( LI ‐ BFR ; n  = 10, 20% 1‐ RM ) or high‐intensity ( HI ; n  = 7, 75% 1‐ RM )]. Bench press 1‐ RM and muscle CSA of triceps brachii ( TB ) and pectoralis major ( PM ) were evaluated before (pre) and after training period (post) as well as after detraining period (detraining). Bench press 1‐ RM was higher at both post and detraining than at pre for LI ‐ BFR ( P <0·01) and the HI ( P <0·01). TB and PM muscle CSA were higher at both post and detraining than at pre for the HI group ( P <0·01), while the LI ‐ BFR group only increased ( P <0·01) at post. Relative dynamic strength (1‐ RM divided by TB muscle CSA ) was higher at both post and detraining than at pre for the HI group ( P <0·01), while the LI ‐ BFR group only increased ( P <0·01) at detraining. In conclusion, increased muscle strength following 6 weeks of training with LI ‐ BFR as well as HI was well preserved at 3 weeks of detraining. HI ‐induced muscle strength appears to be dependent upon both neural adaptations and muscle hypertrophy with training and detraining. On the other hand, LI ‐ BFR ‐induced muscle strength appears to be related primarily to muscle hypertrophy with training and to neural adaptations with detraining.