Normative data of ultrasound quadriceps rectus femoris geometric values. The ECOSARC-2 Study

Abstract

Objectives

To describe geometric muscle ultrasound normative values of Quadriceps Rectus Femoris (QRF) at mid-thigh in Spanish community-dwelling older adults. Secondary objectives included evaluating the associations between ultrasound measurements and physical function, muscle strength, frailty, and dependency in basic activities of daily living.

Design

Cross-sectional study.

Setting

Outpatient clinics of Geriatric Departments at seven University Hospitals and three Primary care settings of Spain.

Participants

424 community-dwelling persons ≥70 years old.

Measurements

Ultrasound measurements were acquired using a Clarius® L7 HD3 probe. QRF thickness (QRFT), QRF area (QRFA), subcutaneous adipose thickness (SAT), total mid-thigh thickness (TTT), and pennation angle (PA) were calculated. Normative values are provided, and associations with comorbidity, dependency, strength, frailty and physical function are described.

Results

Mean age was 81.5 years (range 70−99), 66.7% were female. Mean Barthel index was 93 (SD 11), and mean FRAIL score was 1.1 (1.2). Mean SPPB was 8.7 (SD 2.9) and mean grip strength was 20.7 (8.0). Median values of QRFT, QRFA, SAT, TTT, and PA for women and men were 14.2 / 16.1 mm, 5.4 / 6.4 cm², 15.1 / 9.2 mm, 41.1 / 40.1, and 10.0 / 10.6 respectively. Functional variables were strongly associated with QRFT, QRFA, and TTT in men, and PA with SPPB in both sexes.

Conclusions

The ECOSARC-2 study provides normative values of geometric mid-thigh muscle ultrasound parameters in community-dwelling older adults. These values are essential for determining sex-specific cut-off points for conditions such as sarcopenia, frailty, malnutrition, and for predicting relevant outcomes.