An imbalance in the activation and onset time of the vastus medialis oblique (VMO) and vastus lateralis (VL) muscles may be one of the primary causes of PFPS. Several studies have discussed various exercise methods believed to selectively contract the (VMO) muscle for treating patellofemoral pain syndrome. VMO activity is higher during static closed-chain tasks combined with hip adduction, indicating that performing hip adduction exercises may selectively strengthen the VMO muscle.
Patellofemoral pain syndrome (PFPS) poses challenges in motor control and pain management, especially regarding balanced muscle activation of the vastus medialis oblique (VMO) and vastus lateralis (VL). This study introduces a home-based PFPS rehabilitation approach involving a squat exercise program with hip adduction, examining its effects on motor control and clinical outcomes. Thirty PFPS participants were randomly assigned to conventional squatting (SQU) or squatting with hip adduction (SQU-HA) groups. Participants performed exercises five days a week for 8 weeks, with pre- and post-assessments capturing clinical measures and motor control indicators using electromyography (EMG). This home-based program, integrating hip adduction into squats, enhances motor control, reduces knee stress, and improves daily function, ensuring continued care post-pandemic.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
SINGLE
Enrollment
30
The intervention comprised three sets of 15 repetitions with resting 5-min between sets, followed by IT band stretching for five repetitions. Each participant performed the respective exercise 5 days a week, with 2 days of rest, for 8 weeks.
China Medical University
Taichung, Taiwan
Amplitudes of muscle activation (unit: %MVC)
represented the mean RMSs for each muscle which was normalized by the maximal voluntary contractions (MVC).
Time frame: pre-intervention and after 8-week intervention
VMO/VL ratio
represents the amplitude ratio of VMO relative to VL.
Time frame: pre-intervention and after 8-week intervention
Onset time (unit: msec)
at 200 ms before the beginning of the trial, as the baseline, the onset of EMG activation was identified as the point at which the EMG amplitude was more than three standard deviations from the baseline level for at least 25 ms.
Time frame: pre-intervention and after 8-week intervention
VMO - VL (unit: msec)
represented the onset time differences of VMO relative to VL, with a positive (negative) value indicating a delayed (early) onset time of VMO relative to VL.
Time frame: pre-intervention and after 8-week intervention
Q angle (unit: degree)
The angle was calculated with the intersection formed by two lines crossing the center of the patella. The first line went from the ASIS to the center of the patella and the second from the anterior tuberosity of the tibia to the center of the patella.
Time frame: pre-intervention and after 8-week intervention
The visual analogue scale (VAS) (unit: mm)
VAS was used to assess pain severity. The participants were asked to mark their pain levels on a 100-mm ruler (ranging from 0 = "no pain" to 100 = "unbearable pain") before and after the exercise program.
Time frame: pre-intervention and after 8-week intervention
patellofemoral pain severity scale (PSS) (unit: score)
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PSS was used to measure PFPS associated with functional activities over the past week. The scale comprises 10 items, including climbing/descending stairs, squatting, walking, jogging, running/sprinting, participating in a sport, sitting with knees bent (for 20 min), kneeling, resting, and following an activity. The maximum score was 100 points. The participants rated their pain on a 100-mm VAS, ranging from 0 = "no pain" to 100 = "unbearable pain".
Time frame: pre-intervention and after 8-week intervention