Abstract
BACKGROUND: Sarcopenic obesity (SO) is associated with the highest risk of physical disability. While meta-analyses support resistance training to improve strength and function in this population, the optimal training modality remains unclear. This study compared the effects of high-speed (HSRT) and low-speed resistance training (LSRT) on body composition, hormonal responses, and physical function in adults with SO. METHODS: Seventy-three adults aged > 50 years with sarcopenia and obesity were randomly assigned to the control (n = 26), LSRT (n = 24), or HSRT (n = 23) group. Both LSRT and HSRT groups performed progressive resistance training twice weekly for 16 weeks at 70% 1-RM, differing only in concentric contraction speed. The control group maintained their usual lifestyle throughout the study period. All participants underwent assessments of body composition (by dual-energy X-ray absorption), salivary hormone levels (testosterone, dehydroepiandrosterone sulfate (DHEA-S), and cortisol), and physical function at baseline and after 16 weeks. Physical function was also assessed at mid-term (week 8). Intervention effects were analyzed using two-way repeated-measures ANOVA, with significance set at p < 0.05. RESULTS: Intervention influenced body composition, anabolic hormones, and physical functions of participants (p < 0.05). The LSRT group showed a significant increase in total body muscle mass (+ 1.14%), whereas no such changes were observed in the HSRT or control groups. Salivary DHEA-S levels were maintained in the LSRT and HSRT groups but significantly declined in the control group. Compared to the control group, both LSRT and HSRT groups exhibited significant improvements in all physical function measures at both 8 and 16 weeks. CONCLUSIONS: Both LSRT and HSRT improved physical function and may help maintain certain anabolic markers (such as DHEA-S) in adults with SO. A trivial increase in muscle mass was observed only in the LSRT group. TRIAL REGISTRATION: This study was registered with the Thai Clinical Trial Registry (TCTR) under the registration number TCTR20220107001. The registration was first posted on 07 January 2022, and the study commenced on 24 February 2022.