“…Based on previous studies reporting that hip muscle strength in patients with groin pain or FAI is approximately 10%-35% lower than that in healthy individuals (Casartelli et al, 2011;Frasson et al, 2020;Harris-Hayes et al, 2014;Kloskowska et al, 2016), simulations were performed under three conditions of each muscle for each squat task: full-strength simulation (without muscle weakness), mild muscle weakness (15% decrease), and severe muscle weakness (30% decrease). In the muscle weakened models, before inverse dynamics analysis, muscle volume was modified by 15% and 30% decrease of the original muscle volume against the following muscle for exploring the effects of each muscle volume on hip internal contact force, separately: superior and inferior gluteus maximus (sGlutMax and iGlutMax), anterior and posterior gluteus medius (aGlutMed and pGlutMed), anterior, middle, and posterior gluteus minimus, semitendinosus (ST), semimembranosus (SM), biceps femoris long head (BF), distal, middle, and proximal adductor magnus, gracilis (Grac), adductor longus (AddLong), psoas major, iliacus, rectus femoris, sartorius, tensor fasciae latae, deep external rotator muscles (ExtRot) including piriformis, obturator internus and externus, gemellus superior and inferior, and quadratus femoris, and combined iGlutMax and ExtRot (iGlutMax+ExtRot).…”