Sex-specific associations of body mass index with quadriceps neuromuscular function and self-reported function in individuals with and without patellofemoral pain.

OBJECTIVE

To examine the association of body mass index (BMI) with quadriceps neuromuscular function and self-reported function in individuals with and without patellofemoral pain (PFP).

METHODS

This cross-sectional study included 100 participants (50 PFP, 50 pain-free; evenly split by sex), who were evaluated for BMI, quadriceps neuromuscular function (strength, central activation ratio [CAR], rate of torque development [RTD], and endurance), and self-reported function (Lower Extremity Functional Scale). The association of BMI with quadriceps neuromuscular function and self-reported function was assessed using bivariate correlation analysis, followed by hierarchical regression analysis (covariates: age, physical activity level, pain laterality, pain duration, and pain severity for PFP; age and physical activity level for pain-free).

RESULTS

Higher BMI was associated with lower quadriceps strength (ρ = -0.445; P = .026), slower quadriceps RTD (r = -0.643; P < .001), and poorer self-reported function (r = -0.446; P = .025) among females with PFP; however, higher BMI was only associated with poorer self-reported function (r = -0.401; P = .047) among males with PFP. No significant associations were detected among pain-free females; however, higher BMI was associated with lower quadriceps CAR (ρ = -0.431; P = .032) among pain-free males. After adjusting for covariates, BMI uniquely explained 47 % of the variance in quadriceps RTD (ΔF = 18.73; P < .001) among females with PFP. No other significant regression effects were detected.

CONCLUSIONS

Higher BMI is associated with lower quadriceps neuromuscular function and poorer self-reported function, especially in females with PFP. In particular, BMI accounts for nearly half of the variance in quadriceps RTD in females with PFP.