Handgrip Strength, Appendicular Lean Mass, And Muscle Quality Are Lower In Adults With Down Syndrome

Individuals with Down Syndrome (DS) experience accelerated musculoskeletal aging, including reduced strength, poor body composition, and a higher prevalence of sarcopenia, all of which contribute to functional limitations and increased health risks. Muscle quality index (MQI) offers a simple assessment of muscle efficiency that may be valuable for adults with DS; however, no literature exists comparing MQI differences between individuals with DS against individuals without down syndrome (non-DS). PURPOSE: This study compared MQI, hand grip strength (HGS) and total appendicular lean mass (ALM) between individuals with DS and non-DS. METHODS: Individuals with DS (n = 13) were weight-matched against a group of non-DS. All dependent variables were compared between groups using a Kruskal-Wallis analysis of variance and Cohen’s d effect sizes, with all outcomes reported as mean ± standard deviation. RESULTS: For this sample, 13 DS (5 males; aged: 26.2 ± 8.9 years; height: 149.0 ± 9.7 cm; weight: 72.5 ± 15.8 kg; body mass index: 32.5 ± 5.7 kg/m2) and 13 non-DS (6 males; aged: 21.3 ± 4.6 years; height: 171.2 ± 9.6 cm; weight: 72.5 ± 14.9 kg; body mass index: 24.7 ± 4.5 kg/m2) were included in all analyses. After matching for weight, the DS group showed lower mean values for arm (4.02 ± 1.45 kg vs 6.14 ± 2.58 kg, d = 1.01) and appendicular lean mass (15.78 ± 3.98 kg vs 24.12 ± 7.37 kg, d = 1.42) against the non-DS group. Regarding handgrip, non-DS showed large practical differences for HGSRight, HGSLeft, and HGSTotal when compared to DS (d = 1.62 (right), d = 1.50 (left); d = 1.58, all p < 0.001). Additionally, the non-DS group exhibited large differences in MQIARMS (11.92 ± 1.92, d = 1.41) versus individuals with DS (8.91 ± 2.32). Lastly, MQIALM was greater in non-DS (2.92 ± 0.46, d = 1.04) than the DS group (2.25 ± 0.79). CONCLUSION: Current study findings demonstrate that individuals with DS possess lower HGS, ALM, and MQI compared to non-DS. These findings highlight the need for tailored interventions to enhance muscle health in adults with DS, addressing unique muscle deficits when compared to weight-matched peers without DS. Supported by: Research reported in this abstract was supported by the National Institute of Child and Human Development of the National Institutes of Health under Award Number R21HD115191