Author(s): BONATO, M., MARMONDI, F., GALLI, L., CERIZZA, C., ANNICHIARICO, G., BAGLIVI, A., DELLA TORRE, R., CASTAGNA, A., SCONFIENZA, L.M., BANFI, G., CINQUE, P., Institution: UNIVERSITÀ DEGLI STUDI DI MILANO, Country: ITALY, Abstract-ID: 237

INTRODUCTION:
Sarcopenia is a progressive and generalized decline in muscle strength, mass and physical performance, associated with ageing. These consequences create a major public-health and socio-economic burden due to reduced quality of life and the growing demand for long-term care. Although exercise is considered a cornerstone for prevention and treatment, evidence from long-term randomized controlled trials conducted in real-life, home-based settings remains limited. The Grow Your Muscle (GYM) project was designed to address this gap by testing whether a digitally monitored, home-based resistance-training program delivered via smartphone application could improve muscle functional capacity, body composition and muscle quality over 48 weeks in older adults with sarcopenia. The study specifically aimed to determine whether a greater proportion of participants in the Exercise Group would achieve a clinically meaningful improvement in handgrip strength (≥20%) compared with a Control Group receiving standard lifestyle recommendations.
METHODS:
Sedentary adults ≥60 years with sarcopenia (low appendicular skeletal muscle mass index by bioimpedance analysis and/or low handgrip) were randomized 1:1 to Exercise Group (EG) or Control Group (CG; WHO lifestyle advice). EG completed 4 weekly ~40-min sessions delivered via app (progressive resistance and balance), with chest-strap heart-rate monitoring to quantify adherence and intensity. Assessments at baseline and week 48 (W48) included handgrip, 30-s chair-stand, isometric knee-extensor strength (right/left), Mini-BESTest and 6MWT; body composition by DEXA (arm/leg/total lean mass, ASMMI) and thigh morphology by MRI (CSA, IMAT). Proportions were compared with Chi-square; within-group changes with Wilcoxon; between-group differences with Mann–Whitney.
RESULTS:
Of 196 enrolled participants, 142 (72.4%) completed W48 (drop-out 27.6%). Median adherence in EG was 78% (IQR 59–92). A ≥20% handgrip increase was achieved by 8/73 (11%) in EG vs 0/69 (0%) in CG (p=0.022). EG improved handgrip (p=0.003), chair-stand (p<0.0001), 6MWT (p=0.023), bilateral knee-extensor strength (p<0.0001) and Mini-BESTest (p<0.0001). Between-group differences favored EG for handgrip (p=0.0003), chair-stand (p<0.0001), and knee-extensor strength (right p=0.008; left p=0.012). DEXA showed reduced upper-limb lean mass in both groups (EG p=0.001; CG p=0.029) and increased lower-limb lean mass in EG (p=0.02), without significant between-group differences. MRI showed increased thigh CSA in EG (p=0.032) vs CG (between-group p=0.05), with no IMAT changes.
CONCLUSION:
A 48-week digitally monitored home-based resistance-training program is feasible, safe and clinically effective for improving strength and functional capacity in older adults with sarcopenia, with selective lower-limb morphological adaptations. These findings support scalable, digitally guided long-term exercise prescriptions for real-life sarcopenia management.