What is the primary muscle group involved in trunk flexion while standing during the eccentric phase of the movement?
a. iliopsoas
b. rectus abdominis
c. erector spinae
d. biceps femoris
Answer: c. erector spinae
What is the primary muscle group involved in trunk flexion while standing during the eccentric phase of the movement?
a. iliopsoas
b. rectus abdominis
c. erector spinae
d. biceps femoris
Answer: c. erector spinae