Introduction: Resistance training enhances muscle strength and size; however, high-load exercise (>85% 1RM) may increase the risk of injury. Low-load resistance training with hypoxia or blood flow restriction (BFR) offers safer alternatives, although comparative data are limited. Objective: To examine the effects of hypoxia and BFR on resting growth hormone (GH) levels after five weeks of low-load resistance training. Methods: Thirty male athletes (19–24 years) were assigned to three groups: RT (50% 1RM), RT + HPX (50% 1RM under hypoxia, FiO₂ = 0.137), and RT + BFR (50% 1RM with BFR). Participants performed knee extension and flexion (3 sets × 15 reps, 1-min rest) three times weekly for five weeks. Muscle thickness, strength, resting GH, and blood lactate levels were measured before and after training. Results: After training, RT + HPX and RT + BFR showed significant increases in rectus femoris and biceps femoris thickness. Strength improved in all groups, with knee extension strength higher in the RT+HPX (30.9 ± 16.3%, p = 0.047) than RT (16.1 ± 7.3%). The resting GH levels did not differ significantly between the groups (p > 0.05). Post-exercise lactate increased significantly only in the RT+BFR (68.7 ± 57.2%, p = 0.018). Conclusion: Low-load training with hypoxia or BFR enhances muscle hypertrophy and strength, and hypoxia produces greater strength gain. Resting GH levels appear to be unrelated to these adaptations, suggesting that further studies are needed to clarify the underlying mechanisms.

Low-load resistance training combined with vascular occlusion or hypoxia can increase muscle cross-sectional area (CSA), but the effect of such training on hormonal response and cardiovascular response is less clear. Thirty female netball athletes took part in a 5-week training of knee muscles in which low-load resistance exercise (20% 1-RM) was combined with either an occlusion pressure (KT, n = 10), hypoxic air (HT, n = 10), or no additional stimulus (CT, n = 10). Growth hormones (GHs), cardiovascular parameters, and CSA were measured before and after the training program. Compared to CT, both HT and KT showed a substantial increase in GH release after the first training bout (pre). After 5 weeks of training (post), the release of GH was substantially reduced in all groups. Compared to CT, HT showed a substantial decrease in SP (11.7 ± 11.3%, mean ± 90% CL) over the training period. The reduction in systolic blood pressure (SP) after hypoxic training resulted in a substantial decrease in the rate-pressure product (RPP) by 15.6 ± 9.6%, compared to CT. CSA from HT and KT is likely related to the heightened release of GH found after training. The hypoxic training protocol has a greater cardiovascular benefit than similar resistance training with blood flow restriction.

Background: The growing elderly population faces health problems like osteoporosis, but novel exercises like weighted vests (WV) and whole-body vibration (WBV) may help prevent bone loss. Methods: Thirty-one women aged 60–79 years with osteopenia or osteoporosis (T-score −2.15 ± 0.9) were randomly assigned to three groups: a control group performed exercise only; a whole-body vibration group performed the exercise on a 40 Hz, 2 mm vibration platform; and a weighted vest group performed the exercise while wearing a weighted vest. T-score, bone mineral density (BMD), muscle mass, and physical performance were assessed before and after 8 weeks. Results: The WV showed a greater T-score increase than the CT and WBV groups (WV: 0.08 ± 0.03; CT: −0.18 ± 0.04; WBV: −0.11 ± 0.16; p = 0.01, 95%CI). Leg BMD increased in the WV group (1.75 ± 0.13 to 1.79 ± 0.16 g/cm²; p = 0.02). Leg lean mass also increased in the WV (1.28 ± 0.91 kg) compared to WBV (0.17 ± 0.14 kg) and CT (0.06 ± 0.79 kg, p = 0.01, 95%CI). The WV group showed greater physical performance improvements (5TSTS and 6-MWT). The WBV group showed improved total lean mass compared to the CT group (WBV: 0.32 ± 0.17; CT = −1.20 ± 1.86, p = 0.006, 95%CI). Conclusions: WV exercise improved bone density, leg lean mass, and physical performance in older women. WBV exercise increased total lean mass and skeletal muscle index while reducing fat mass. WV exercise provides an additive effect beyond exercise alone or WBV.