Fig. 1

3D ultrasound methodology. (A) Ultrasound scans of the vastus lateralis were collected in longitudinal direction distally to proximally, covering the entire muscle belly. Location and orientation of the ultrasound probe were collected over time using a cluster marker set attached to the ultrasound probe, traced by a pose tracking device, enabling the construction of a 3D vastus lateralis muscle. (B) Representative example of a 3D ultrasound image reconstruction. (C) A segmented vastus lateralis anatomical cross-sectional area at 50% muscle length in the transversal plane using reconstructed images.