Conor Theiss1, Sarah Martinez-Sepanski1, Kelton Mehls2, Dave Clark1. 1Middle Tennessee State University, Murfreesboro, TN. 2Duquesne University, Pittsburgh, PA.

BACKGROUND: Patellofemoral pain (PFP) is described as generalized knee pain behind or along the medial and/or lateral border(s) of the patella. The etiology of PFP is not fully understood; however, impaired motor control and quadriceps weakness is thought to be related to this disorder, which has been shown to lead to decreased quality of life. There has been little research on differences in muscle activity during functional movements of agonist/antagonist groups or synergistic groups in women with PFP. The purpose of this study was to determine whether women with PFP would exhibit different muscle activity patterns during functional movements, when compared to a control group. METHODS: The experimental group included those who self-reported anterior or retro-patellar pain during at least two of the following activities: kneeling, prolonged sitting, squatting, ascending stairs, descending stairs, jumping, hopping or running. Those that self-reported no pain and presented no other joint issues were placed in the control group. Participants were excluded if they presented a history of joint surgery, patellar dislocation, and signs or symptoms of any joint injury or pain that would prevent completion of any activity required for data collection. Muscle activity, using surface electromyography (sEMG), was assessed on the gluteus medius (GMED), gluteus maximus (GMAX), abductor longus (AL), and the tensor fasciae latae (TFL) during 5 reps of forward lunge, lateral step down, and single leg squat. Statistical analysis included independent samples t-tests to compare normalized peak activity of the previously listed muscles between groups, and Hedge's g was used to calculate effect sizes. RESULTS: Regarding sEMG, GMED, GMAX, and AL were not significantly different between groups across any movement; however, peak TFL was significantly higher in the experimental group during the descent phase (p = .015, g = -1.13), and ascent phase (p = .010, g = -1.13) of the forward lunge. In addition, peak TFL was significantly higher in the experimental group during the descent phase of the lateral step down (p = .042, g = -1.80). Lastly, peak TFL was significantly higher in the experimental group during the ascent phase (p = .046, g = -0.90) of the single leg squat. CONCLUSION: The experimental group, or those who had PFP, demonstrated higher peak TFL activity during functional movements. This could be indicative of increased TFL activation to provide stability in the lower extremity during functional tasks; however, future research would be needed to fully understand the relationship between PFP and these muscles.

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