Short foot exercises have additional effects on knee pain, foot biomechanics, and lower extremity muscle strength in patients with patellofemoral pain

BACKGROUND: Patellofemoral pain (PFP) is a common knee problem. The foot posture in a relaxed stance is reported as a distal factor of PFP. However, the effects of short foot exercise (SFE) on the knee and functional factors have not yet been investigated in patients with PFP. OBJECTIVE: This study aimed to investigate the additional effects of SFE on knee pain, foot biomechanics, and lower extremity muscle strength in patients with PFP following a standard exercise program. METHODS: Thirty patients with a `weak and pronated' foot subgroup of PFP were randomized into a control group (ConG, n = 15) and a short foot exercise group (SFEG, n = 15) with concealed allocation and blinded to the group assignment. The program of ConG consisted of hip and knee strengthening and stretching exercises. SFEG program consisted of additional SFE. Both groups performed the supervised training protocol two times per week for 6 weeks. Assessment measures were pain visual analog scale (pVAS), Kujala Patellofemoral Score (KPS), navicular drop test (NDT), rearfoot angle (RA), foot posture index (FPI), and strength tests of the lower extremity muscles. RESULTS: Both groups displayed decreases in pVAS scores, but it was only significant in favor of SFEG. NDT, RA, and FPI scores decreased in SFEG whereas they increased in ConG. There was a significant group-by-time interaction effect in hip extensor strength and between-group difference was found to be significantly in favor of SFEG. CONCLUSIONS: An intervention program consisting of additional SFE had positive effects on knee pain, navicular position, and rearfoot posture. An increase in the strength of the hip extensors may also be associated with improved stabilization by SFE.