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Background: Patellofemoral pain syndrome (PFPS) is a prevalent musculoskeletal disorder marked by anterior knee pain and functional impairment. Although quadriceps weakness is considered a key contributor, evidence regarding its association with clinical factors in middle-aged adults remains limited. This study aimed to assess quadriceps muscle strength in individuals with PFPS and examine its relationship with body mass index (BMI), working hours, and symptom laterality.
Methods: A cross-sectional study was conducted involving 303 adults aged 35–60 years with clinically diagnosed PFPS, recruited from a tertiary care outpatient department. Quadriceps strength was evaluated bilaterally using Manual Muscle Testing (MMT). Demographic data, BMI, occupational status, working hours, and the affected limb were recorded. Descriptive statistics and comparative analyses between affected and unaffected limbs were performed.
Results: The mean age of participants was 44.67 ± 5.72 years, with females comprising 63.4% of the sample. A majority of participants were overweight or obese (77.2%). Quadriceps strength was significantly reduced in the affected limb (mean MMT 1.97 ± 0.78) compared with the unaffected side (left: 4.21 ± 0.81; right: 4.18 ± 0.74). Symptoms were most commonly observed in the left limb (38.0%), followed by the right (32.3%) and bilateral involvement (29.7%). Higher BMI and longer working hours were significantly associated with decreased quadriceps strength (p < 0.05).
Conclusion: Middle-aged adults with PFPS demonstrate significant quadriceps strength deficits in the affected limb. Increased BMI and prolonged working hours further contribute to strength reduction, highlighting the importance of individualized rehabilitation programs addressing these modifiable risk factors. Future studies employing objective strength assessment methods are warranted.
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