Methods <p>One hundred seventy patients were enrolled in this study and 141 patients were analyzed. Hand grip strength (HGS) was measured with Jamar dynamometer, muscle mass was measured with ultrasound, and sarcopenia diagnosis based on low muscle strength and low muscle mass. Muscle specific strength is calculated as HGS to muscle thickness (kg/cm) and cross-sectional area (kg/cm²). Osteoporosis is diagnosed if the T score was below − 2.5 or fragility fracture is present. The patients with both osteoporosis and sarcopenia were accepted as osteosarcopenia.</p> Results <p>Mean age of the patients was 76.86 ± 6.74 and 121 (71.2%) were female. Ten percent of the patients was osteoporotic, 25.9% was sarcopenic and 27.1% was osteosarcopenic. In patients with osteosarcopenia, HGS/ Rectus femoris thickness (kg/cm) was 11.35 (2.47–37.5); HGS / Rectus femoris cross sectional area (kg/cm2) was 5.16 (0.82–27.3) and HGS/ Quadriceps femoris thickness (kg/cm) was 5.4 (1.43–13.04). When compared to control, osteoporosis and sarcopenia groups, muscle specific strength was lower in the osteosarcopenia group (p &lt; 0.001, p = 0.009, p &lt; 0.001, respectively). Linear regression analyses revealed that muscle specific strength was significantly associated with timed up and go (TUG) (β = − 0.236, p = 0.030) and L1-L4 T score (β = − 0.233, p = 0.032).</p> Conclusion <p>Muscle specific strength- especially rectus femoris and quadriceps femoris thickness—is associated with TUG and L1-L4 scores in osteosarcopenia patients.</p>