Skeletal Muscle Index (SMI) Lab

Skeletal Muscle Index (SMI)

Appendicular Lean Mass & Sarcopenia Screening

Biometric Data

Biological Sex

Weight Unit

Weight (LBS)

Body Fat %

Height Unit

Height (CM)

Your SMI Score (kg/m²):

Clinical Classification:

SMI Norms for Masters Athletes (50+)

Sarcopenia Risk (Low Muscle Mass) Men: <7.0 | Women: <5.7

Average (Healthy Baseline) Men: 7.0–8.5 | Women: 5.7–7.0

High (Strong Sarcopenia Defense) Men: 8.5–9.5 | Women: 7.0–8.0

Elite (Academic Athlete Tier) Men: >9.5 | Women: >8.0

Higher SMI correlates with better mobility, metabolic health, and reduced frailty risk in later decades.

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[ Awaiting biometric data for sarcopenia risk calculation ]

Research: SMI vs Functional Aging

The Formula

The Skeletal Muscle Index (SMI) measures **Appendicular Lean Soft Tissue (ALST)** relative to the square of your height. Unlike BMI, which aggregates fat and bone, SMI isolates the functional engine. For the athlete 50+, this is the primary biomarker for mobility preservation.

Sarcopenia Prevention

Clinical thresholds (< 7.0 for men, < 5.7 for women) represent the "disability zone." Academic Athletes target the performance tier to buffer against the 1-2% annual muscle loss typically seen after age 50.

Male Elite: > 9.0
Female Elite: > 7.5

Diagnostic Disclaimer: This calculation uses an ALST estimation based on total lean body mass. For clinical precision, a DEXA scan (Appendicular Lean Mass) is required.