Epimuscular myofascial force transmission between the levator scapulae muscle and the upper fiber of the serratus anterior or rhomboid minor muscles

This study investigated the epimuscular myofascial force transmission between the levator scapulae, serratus anterior, and rhomboid minor muscles. The participants included 10 healthy males (a total of 20 shoulders). Differences in the shear moduli of the levator scapulae, serratus anterior, and rhomboid minor muscles were measured in the resting and levator scapulae stretching positions using shear wave elastography. The correlation between the rates of change for each muscle was also verified. The results demonstrated a notable increase in the shear modulus from the resting to stretching positions for levator scapulae (42.9 ± 17.6 kPa vs. 52.4 ± 15.2 kPa) and serratus anterior (32.8 ± 12.9 kPa vs. 58.4 ± 18.5 kPa) (P = 0.02, P