We examined the effects of walk training combined with leg blood flow reduction (BFR) on muscle hypertrophy as well as on peak oxygen uptake (VO₂ peak) in older individuals. Both the BFR walk training (BFR-Walk, n = 10, age; 64 ± 1 years, body mass index [BMI]; 22.5 ± 0.9 kg/m²) and control walk training (CON-Walk, n = 8, age; 68 ± 1 years, BMI; 23.2 ± 1.0 kg/m²) groups performed 20 minutes of treadmill walking at an exercise intensity of 45% of heart rate reserve, 4 days per week, for 10 weeks. The BFR-Walk group wore pressure belts (160-200 mm Hg) on both legs during training. After the training, magnetic resonance imaging-measured thigh muscle cross-sectional area (3.1%, p < .01) and muscle volume (3.7%, p < .01) as well as maximal isometric (5.9%, p < .05) and isokinetic (up to 22%, p < .01) strength increased in the BFR-Walk group, but not in the CON-Walk group. Estimated VO₂ peak during a bicycle graded exercise test increased (p < .05) and correlated with oxygen pulse in both groups. In conclusion, BFR walk training improves both muscle volume and strength in older women.

We investigated the combined effect of low-intensity blood flow restriction and high-intensity resistance training on muscle adaptation. Forty young men (aged 22-32 years) were randomly divided into four groups of ten subjects each: high-intensity resistance training (HI-RT, 75% of one repetition maximum [1-RM]), low-intensity resistance training with blood flow restriction (LI-BFR, 30% 1-RM), combined HI-RT and LI-BFR (CB-RT, twice-weekly LI-BFR and once-weekly HI-RT), and nontraining control (CON). Three training groups performed bench press exercises 3 days/week for 6 weeks. During LI-BFR training sessions, subjects wore pressure cuffs on both arms that were inflated to 100-160 mmHg. Increases in 1-RM were similar in the HI-RT (19.9%) and CB-RT (15.3%) groups and lower in the LI-BFR group (8.7%, p < 0.05). Maximal isometric elbow extension (MVC) increased in the HI-RT (11.3%) and CB-RT (6.6%) groups; there was no change in the LI-BFR group (-0.2%). The cross-sectional area (CSA) of the triceps brachii (TB) increased (p < 0.05) in the HI-RT (8.6%), CB-RT (7.2%), and LI-BFR (4.4%) groups. The change in relative isometric strength (MVC divided by TB CSA) was greater (p < 0.05) in the HI-RT group (3.3%) than in the LI-BFR (-3.5%) and CON (-0.1%) groups. Following training, relative dynamic strength (1-RM divided by TB CSA) was increased (p < 0.05) by 10.5% in the HI-RT group and 6.7% in the CB-RT group. None of the variables in the CON group changed. Our results show that low-intensity resistance training with BFR-induced functional muscle adaptations is improved by combining it with HI-RT.

We examined the effects of high-intensity resistance training (HIT) and low-intensity blood flow-restricted (LI-BFR) resistance training on carotid arterial compliance. Nineteen young men were randomly divided into HIT (n = 9) or LI-BFR (n = 10) groups. The HIT and LI-BFR groups performed 75 and 30 %, respectively, of one-repetition maximum (1-RM) bench press exercise, 3 days per week for 6 weeks. During the training sessions, the LI-BFR group wore elastic cuffs around the most proximal region of both arms. Muscle cross-sectional area (CSA), 1-RM strength, and carotid arterial compliance were measured before and 3 days after the final training session. Acute changes in systolic arterial pressure (SAP), plasma endothelin-1 (ET-1), nitrite/nitrate (NOx), and noradrenalin concentrations were also measured during and after a bout of training session. The training led to significant increases (P < 0.01) in bench press 1-RM and arm and chest muscle CSA in the two training groups. Carotid arterial compliance decreased significantly (P < 0.05) in the HIT group, but not in the LI-BFR group. There was a significant correlation (r = -0.533, P < 0.05) between the change in carotid arterial compliance and the acute change in SAP during training sessions; however, ET-1 and NOx did not correlate with carotid arterial compliance. Our results suggest that muscle CSA and strength increased following 6 weeks of both HIT and LI-BFR training. However, carotid arterial compliance decreased in only the HIT group, and the changes were correlated with SAP elevations during exercise sessions.

High-intensity resistance training increases muscle size, but reduces arterial compliance. Muscular blood flow reduction (BFR) during low-intensity training has been shown to elicit muscle hypertrophy. However, the effect on arterial compliance is unknown. We examined the effects of walk training with BFR on carotid arterial compliance and muscle size in the elderly adults. Both BFR-walk training (BFR-W, n = 13, 66 ± 1 year) and control-walk training (CON-W, n = 10, 68 ± 1 year) groups performed 20 minutes treadmill walking at an exercise intensity of 45% of heart rate reserve, 4 days/week for 10 weeks. The BFR-W group wore pressure cuffs on both legs during training. Maximum knee joint strength (∼15%) and MRI-measured thigh muscle cross-sectional area (3%) increased in the BFR-W, but not in the CON-W. Carotid arterial compliance improved in both BFR-W (50%) and CON-W (59%) groups. Walk training with blood flow reduction can improve thigh muscle size/strength as well as carotid arterial compliance, unlike high-intensity training, in the elderly.

It is an undeniable fact that resistance training (RT) is a potent stimulus for muscle hypertrophy and strength gain, but it is less understood whether RT can increase maximal aerobic capacity (VO 2 max). The purpose of this brief review is to discuss whether or not RT enhances VO 2 max in young (20-40 years) and older subjects (>60 years). Only 3 of 17 studies involving young subjects have indicated significant increases in VO 2 max following RT, while six of nine studies in older subjects have reported significant improvements in VO 2 max following RT. There was a significant negative correlation between the initial VO 2 max and RT-induced change in VO 2 max. This result suggests that RT-induced increase in VO 2 max is dependent upon the subject's initial VO 2 max. The RT-induced increase in VO 2 max may be elicited when their initial relative VO 2 max is lower than 25 ml/kg/min for older subjects and lower than 40 ml/kg/min for young subjects. Thus, RT can be expected to improve concurrently both muscular and cardiovascular fitnesses within a single mode of RT when young and old persons have initially low fitness levels.

To investigate the effects of a single high-load (80% of one repetition maximum [1RM]) set with additional drop sets descending to a low-load (30% 1RM) without recovery intervals on muscle strength, endurance, and size in untrained young men. Nine untrained young men performed dumbbell curls to concentric failure 2-3 days per week for 8 weeks. Each arm was randomly assigned to one of the following three conditions: 3 sets of high-load (HL, 80% 1RM) resistance exercise, 3 sets of low-load [LL, 30% 1RM] resistance exercise, and a single high-load (SDS) set with additional drop sets descending to a low-load. The mean training time per session, including recovery intervals, was lowest in the SDS condition. Elbow flexor muscle cross-sectional area (CSA) increased similarly in all three conditions. Maximum isometric and 1RM strength of the elbow flexors increased from pre to post only in the HL and SDS conditions. Muscular endurance measured by maximum repetitions at 30% 1RM increased only in the LL and SDS conditions. A SDS resistance training program can simultaneously increase muscle CSA, strength, and endurance in untrained young men, even with lower training time compared to typical resistance exercise protocols using only high- or low-loads.

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Low-intensity NMES-BFR induces muscle hypertrophy and strength gain in untrained young male participants.