Overweight and obesity in young adults with patellofemoral pain:Impact on functional capacity and strength

Purpose:This study aimed to(a)investigate the proportion of overweight/obesity in a cohort of young adults with patellofemoral pain(PFP)and(b)explore the association of body mass index(BMI),body fat,and lean mass with functional capacity and hip and knee strength in people with PFP.Methods:We included a mixed-sex sample of young adults(18-35 years old)with PFP(n=100).Measurements for BMI,percentage of body fat,and lean mass(assessed by bioelectrical impedance)were obtained.Functional capacity was assessed by the Anterior Knee Pain Scale,plank test,and single-leg hop test.Strength of the knee extensors,knee flexors,and hip abductors was evaluated isometrically using an isokinetic dynamometer.The proportion of overweight/obesity was calculated based on BMI.The association between BMI,body fat,and lean mass and functional capacity and strength was investigated using partial correlations,followed by hierarchical regression analysis,adjusted for covariates(sex,bilateral pain,and current pain level).Results:A total of 38%of our cohort had their BMI categorized as overweight/obese.Higher BMI was associated with poor functional capacity(ΔR^(2)=0.06-0.12,p<0.001)and with knee flexion strength only(ΔR^(2)=0.04,p=0.030).Higher body fat was associated with poor functional capacity(ΔR^(2)=0.05-0.15,p≤0.015)and reduced strength(ΔR^(2)=0.15-0.23,p<0.001).Lower lean mass was associated with poor functional capacity(ΔR^(2)=0.04-0.13,p≤0.032)and reduced strength(ΔR^(2)=0.29-0.31,p<0.001).Conclusion:BMI,body fat,and lean mass should be considered in the assessment and management of young people with PFP because it may be detrimental to function and strength.

Exploring overweight and obesity beyond body mass index:A body composition analysis in people with and without patellofemoral pain

Background:We compared body mass index(BMI),body fat,and skeletal muscle mass between(1) a mixed-sex nonathletic cohort of people with patellofemoral pain(PFP) and pain-free people,and(2) a nonathletic cohort of people with PFP and pain-free people subgrouped by sex(i.e.,men and women with PFP vs.pain-free men and women).Methods:This cross-sectional study included 114 people with PFP(71 women,43 men) and 54 pain-free controls(32 women,22 men).All participants attended a single testing session to assess body composition measures,which included BMI,percentage of body fat(%BFBioimpedance),and skeletal muscle mass(both assessed by bioelectrical impedance analysis),and percentage of body fat(%BFskinfoid)(assessed by skinfold caliper analysis).A one-way univariate analysis of covariance(age and physical activity levels as covariates) was used to compare body composition measures between groups(i.e.,PFP vs.pain-free group;women with PFP vs.pain-free women;men with PFP vs.pain-free men).Results:Women with PFP presented significantly higher BMI,%BFBiompedance,and %BFSkinfold,and lower skeletal muscle mass compared to pain-free women(p≤0.04;effect size:-0.47 to 0.85).Men with PFP and men and women combined had no differences in BMI,%BFBioimpedance,%BFSkinfold,and skeletal muscle mass compared to their respective pain-free groups(p> 0.05).Conclusion:Our findings indicate that BMI and body composition measures should be considered as part of the evaluation and management of people with PFP,especially in women,who have demonstrated higher BMI and body fat and lower skeletal muscle mass compared to pain-free controls.Future studies should not assess body composition measures in a mixed-sex population without distinguishing men participants from women participants.