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Background: Systemic lupus erythematosus (SLE) is a multisystem autoimmune disease that can affect multiple organs, including the musculoskeletal system [1]. Although evidence is mixed, people with SLE may exhibit reductions in muscle mass, muscle strength (the ability to exert force), and muscle power (the ability to generate force rapidly) compared with healthy controls and other disease populations [2, 3], increasing their risk of sarcopenia [4]. Muscle strength and power are key predictors of physical function and mortality in the general population [5]. Importantly, in individuals with SLE, greater muscle strength and power have been associated with lower tissue damage [6], reduced fatigue, and better quality of life [2]. This underscores the clinical relevance of identifying effective strategies to improve muscle mass, strength, and power, including structured exercise programs.
Objectives: To evaluate the effects of a 12-week walking-based aerobic exercise intervention on muscle mass, strength, and power in women with SLE.
Methods: This study reports secondary outcomes of a non-randomized clinical trial (NCT03107442). Fifty-eight women with SLE with mild disease activity were allocated to an exercise group (n = 26) or a control group (n = 32). The intervention consisted of a 12-week progressive brisk walk exercise program performed on a treadmill (2 sessions/week, 75 min/session) at 40–75% of heart rate reserve, following American College of Sports Medicine guidelines for aerobic exercise [7]. The control group received verbal advice on healthy lifestyle habits. Muscle mass was assessed by bioelectrical impedance analysis. Muscle strength was evaluated using handgrip strength (kg), and relative muscle strength was calculated as handgrip strength divided by muscle mass (kg). Muscle power was assessed using the 30-s chair stand test to estimate sit-to-stand power (W) [8], and relative muscle power was calculated as power output divided by muscle mass (kg). A total of 54 participants completed all assessments (exercise n = 26; control n = 28), and 49 were included in the per-protocol analysis (exercise attendance ≥75%). Groups were comparable at baseline with respect to age, disease duration, disease activity, sociodemographic characteristics, body mass index, and corticosteroid use. Between-groups differences in changes from baseline at week 12 were analyzed using an analysis of covariance (ANCOVA), including the dependent variable at baseline as a covariate.
Results: Table 1 shows baseline and 12-week changes in outcome measures. No significant between-group differences were observed in muscle mass, muscle strength, or muscle power from baseline to week 12 (all P > 0.05) in the complete-case analysis, with consistent results in the per-protocol analysis.
Conclusions: A 12-week aerobic exercise program did not improve muscle mass, strength or power in adult women with SLE with mild disease activity. Although this intervention has previously been shown to enhance cardiorespiratory fitness [9], these findings support the stimulus-specific nature of exercise adaptations. Consequently, commonly recommended aerobic activities in clinical practice such as brisk walking may be insufficient to induce meaningful neuromuscular adaptations. Improvements in muscle mass, strength, and power likely require more targeted exercise strategies, and future interventions incorporating resistance and high-velocity training should be explored in this population.
Complete-case analysis assessing the effects of a 12-week walking–based exercise intervention on muscle mass, strength, and power in women with systemic lupus erythematosus.
| Change from baseline | Exercise group (n=26) | Control group (n=28) | Exercise vs. Control | |||||
|---|---|---|---|---|---|---|---|---|
| Mean | SE | Mean | SE | Mean difference | 95% CI | P | ||
| Muscle Mass (kg) | 0,2 | 0,5 | 1,1 | 0,5 | -0,9 | -2,4 | 0,6 | 0,222 |
| % Muscle mass | 0,2 | 0,5 | 1,1 | 0,5 | -0,9 | -2,5 | 0,6 | 0,215 |
| Muscle Strength - Handgrip (kg) | -0,9 | 0,5 | -0,3 | 0,4 | -0,6 | -1,9 | 0,7 | 0,358 |
| Relative muscle strength
| 1,0 | 0,0 | 1,0 | 0,0 | 0,0 | -0,1 | 0,1 | 0,719 |
| Muscle Power (W) | 1,2 | 0,6 | 1,8 | 0,5 | -0,5 | -2,1 | 1,0 | 0,493 |
| Relative Muscle Power
| 0,1 | 0,0 | 0,1 | 0,0 | 0,0 | -0,1 | 0,1 | 0,929 |
Between-groups differences in changes from baseline at week 12 were analyzed using an analysis of covariance (ANCOVA). The analyses were adjusted for baseline values. CI, confidence interval; SE, standard error.
REFERENCES: [1] Siegel CH, Sammaritano LR. JAMA. 2024;331:1480–91.
[2] Balsamo S, et al. BMC Musculoskelet Disord. 2013;14:263.
[3] Peña É, et al. Clin Rheumatol. 2023;42:1237–48.
[4] Santos MJ, et al. Clin Exp Rheumatol. 2011;29:470–6.
[5] Araújo CGS, et al. Mayo Clin Proc. 2025;100:1319–31.
[6] Hernández-Martínez A, et al. ECSS Book of Abstracts. 2022.
[7] Garber CE, et al. Med Sci Sports Exerc. 2011;43:1334–59.
[8] Alcazar J, et al. Sci Rep. 2020;10:1–8.
[9] Soriano-Maldonado A, et al. J Clin Med. 2018;7:E477.
Acknowledgments: NIL.
Disclosure of Interests: None declared.