Type 2 diabetes mellitus (T2DM) is a prevalent, chronic metabolic disease. Sodium-glucose cotransporter-2 (SGLT2) inhibitors and aerobic exercise (AE) have shown promise in mitigating insulin resistance (IR) and T2DM. This study investigated the effects of dapagliflozin (Dapa) monotherapy and combined AE on mitochondrial quality control (MQC) in skeletal muscle and IR in T2DM rats. T2DM rats, induced by a high-fat diet/streptozotocin model, were randomly assigned to the following groups: T2DM+vehicle group (DMV), T2DM rats treated with Dapa (DMDa, 10 mg/kg/d), T2DM rats subjected to combined Dapa treatment and AE (DMDa+AE), and the standard control group (CON). Blood and skeletal muscle samples were collected after 6 weeks of intragastric administration and treadmill exercise. The results showed that DMDa monotherapy could reduce the accumulation of white adipose tissue and skeletal muscle lipid droplets and improve HOMA-IR. While the combined AE led to further reductions in subcutaneous white adipose tissue and fasting glucose levels, it did not confer additional benefits in terms of HOMA-IR. Furthermore, Dapa monotherapy enhanced skeletal muscle mitochondrial biogenesis (PGC-1α, NRF1, TFAM, and COX IV), mitochondrial dynamics (OPA1, DRP1, and MFN2), and mitophagy (PGAM5 and PINK1) related protein levels. Nevertheless, the combination of Dapa with AE treatment did not yield an additive effect. In conclusion, this study highlights the potential of SGLT2 inhibitors, specifically Dapa, in ameliorating IR and maintaining MQC in skeletal muscle in rats with T2DM. However, combined AE did not produce an additive effect, indicating the need for further research.

This meta-analysis examined the efficacy of low-load resistance training with blood flow restriction (LL-BFR) versus high-load resistance training (HL-RT) on muscle strength and hypertrophy, exploring factors affecting outcomes. We searched Embase, CNKI, Wanfang, PubMed, Ovid Medline, ProQuest, Cochrane Library, Embase, and Scopus from inception to July 2024. After assessing the risk of bias using the Cochrane tool, a meta-analysis was conducted to calculate the overall effect size. Subgroup analyses were performed to explore the impact of different modulating factors on training effects. LL-BFR was found to be inferior to HL-RT with regard to muscle strength gains (SMD = −0.33, 95% CI: −0.49 to −0.18, p < 0.0001). However, subgroup analyses revealed that LL-BFR achieved muscle strength gains comparable to HL-RT under individualized pressure (SMD = −0.07, p = 0.56), intermittent cuff inflation (SMD = −0.07, p = 0.65), and a higher number of training sessions (SMD = −0.12, p = 0.30). No significant difference in muscle mass gains was observed between LL-BFR and HL-RT (SMD = 0.01, p = 0.94), and this conclusion remained consistent after controlling for modulating variables. HL-RT is superior to LL-BFR in enhancing muscle strength gains. Nevertheless, under appropriate conditions, including individualized pressure prescription, intermittent cuff inflation, and a higher number of training sessions, LL-BFR can achieve muscle strength gains comparable to HL-RT, emphasizing the importance of tailored training programs. Both methods exhibit similar effects on muscle mass gains, indicating that LL-BFR serves as an effective alternative for individuals who cannot perform HL-RT because of physical limitations or injury concerns.

Beetroot juice (BRJ) supplementation has the potential to enhance the effects of blood flow restriction (BFR) training in improving muscle strength and fatigue resistance; however, evidence supporting their combined effects remains limited. This study investigated whether BRJ supplementation enhances the effects of BFR training on muscle strength and fatigue resistance. This randomized, double-blind, placebo-controlled trial included 20 male university students from the School of Sports, who were randomly assigned to a BFR group (n = 10, age: 21.9 ± 1.7 years) or a BFR + BRJ group (n = 10, age: 21.8 ± 1.5 years; nitrate: 8 mmol/day). Participants completed a one-week BRJ pre-supplementation phase followed by a four-week bilateral knee extensor/flexor BFR training program (40% limb occlusion pressure, 30% of peak torque load), performed three times per week. Knee extensor and flexor strength (at 60°/s, 180°/s, and MVIC) and countermovement jump (CMJ) performance were assessed using an isokinetic dynamometer and a force plate pre- and post-intervention. Both the four-week BFR and BFR+BRJ interventions significantly increased the relative peak torque of the knee extensors/flexors at 60°/s (Left: p_pre-post = 0.23, d = -0.89, ηp²_Time = 0.775; Right: p_pre-post = 0.017, d = -0.63, ηp²_Time = 0.744), 180°/s (Left: p_pre-post = 0.028, d = -1.32, ηp²_Time = 0.319; Right: p_pre-post = 0.007, d = -1.48, ηp²_Time = 0.822), and MVIC (Left: p_pre-post = 0.007, d = -0.11, ηp²_Time = 0.825; Right: p_pre-post = 0.009, d = -1.31, ηp²_Time = 0.842). They also improved the torque of the knee extensors in both the left and right legs during the 100-repetition maximal voluntary contraction test at 90°/s, with both initial (first 20 reps) and final (last 20 reps) values significantly increased (Left: p_pre-post = 0.029, d = -0.96, ηp²_Time = 0.612; Right: p_pre-post = 0.007, d = -1.21, ηp²_Time = 0.725). The CMJ test showed significant improvements in fatigued bilateral CMJ height (p_pre-post = 0.048, d = -0.534, ηp²_Time = 0.556), peak force (p_pre-post = 0.047, d = -0.913, ηp²_Time = 0.444), and rate of force development (RFD; p_pre-post = 0.044, d = -0.902, ηp²_Time = 0.656) following both BFR and BFR + BRJ interventions. Notably, single-leg countermovement jump performance showed no significant improvements for either the left or right leg. Notably, post-intervention, only the BFR+BRJ group showed significant improvements in fatigued bilateral CMJ height (p_pre-post = 0.012, d = -1.307, ηp²_Time = 0.846). The results indicate that four weeks of BFR training, with or without BRJ supplementation, can improve knee flexor and extensor strength and bilateral CMJ performance. However, the effects of BRJ were selective rather than broadly superior, as BRJ mainly enhanced BFR training by reducing fatigue-related declines in vertical jump performance.