Table 5. Reference values in healthy people detected with US.
| Parameter | Reference | Male | Female |
|---|---|---|---|
| RF muscle thickness | Minetto et al. (75), 2016 | 20 mm* | 16 mm* |
| Mean age: 26±3 years | |||
| Delaney et al. (85), 2010 | 2.3±0.3 cm; mean age: 24.6±1.45 years | N/A** | |
| Ema et al. (78), 2013 | 20.7±3.9 mm; mean age: 24±1 years | ||
| Strasser et al. (76), 2013 | 18.1±4 mm; mean age: 24.2±3.7 years | ||
| RF CSA | Seymour et al. (70), 2009 | 463±137 mm2; mean age: 63±9 years | |
| Delaney et al. (85), 2010 | 8.8±2.1 cm2; mean age: 24.6±1.45 years | N/A** | |
| QMLT | Tillquist et al. (71), 2014 | 2.01–2.09±0.50–0.52 cm; mean age: 30.6±8.4 years | |
| Arts et al. (77), 2010 | R: 4.16±1.02 cm; L: 4.07±0.97 cm; mean age: 47 years | R: 3.64±0.76 cm; L: 3.57±0.72 cm; mean age: 48 years | |
| PA | Strasser et al. (76), 2013 | RF***: –; musculus intermedius: 9.7°±2.6°; vastus lateralis: 14.7°±2.5°; vastus medialis: 12.1°±2°; mean age: 24.2±3.7 years | |
| EI**** | Strasser et al. (76), 2013 | RF: 101.9±14; musculus intermedius: 77.7±20.1; vastus lateralis: 96.2±14.9; vastus medialis: 94.3±17.8; mean age: 24.2±3.7 years | |
*, Values 2 SDs below the sex-specific means of the sample of young subjects have been taken from the indicated reference (cut-off values used to detect low muscle mass in the indicated study). **, Female gender not included in the study. ***, The orientation of the fibers of the RF was almost parallel to their fascia, so no PA was determined. ****, EI assessed with ImageJ (National Institutes of Health, USA) software. RF, rectus femoris; CSA, cross-sectional area; QMLT, quadriceps muscle layer thickness; R, right. L, left; PA, pennation angle; EI, echo intensity.