Is lower limb muscle power by vertical jump a sensitive and specific measure for screening sarcopenia compared to...

Muscle power declines earlier and more sharply than strength with aging, yet it is not included in sarcopenia diagnosis, partly due to limitations in assessment methods.

To evaluate the sensitivity and specificity of vertical jump performance, measured via a mobile app, for sarcopenia screening and compare its accuracy with established strength tests.

This cross-sectional study included 214 older adults (mean age 70.6, range 60-88 year; 84.6% women) without mobility limitations. Sarcopenia was defined using the European Working Group on Sarcopenia in Older People (EWGSOP2) algorithm (low muscle strength and mass). Jump height was measured using an app, and power was estimated using a validated equation. Sensitivity, specificity, and area under the curve (AUC) were analyzed using Receiver Operating Characteristic (ROC) curves.

Sarcopenia prevalence was 4.7%, and probable sarcopenia was 12.1%. Jump height showed 50% sensitivity, 92.5% specificity, and an AUC of 0.7349. Jump power demonstrated higher discriminative ability (90% sensitivity, 82.1% specificity, AUC 0.9146), comparable to handgrip strength (90% sensitivity, 93.6% specificity, AUC 0.8824). The FTCS test showed lower accuracy when based on time (88.9% sensitivity, 45.1% specificity, AUC 0.701), while power estimation improved performance to diagnosis (77.8% sensitivity, 80.9% specificity, AUC 0.8489).

Vertical jump power showed high sensitivity and specificity for sarcopenia screening, suggesting its potential as a sarcopenia tool. However, among the tests evaluated, the handgrip appears to be the most accurate and most effective, because it can be applied to older adults with restricted mobility in their lower limbs.