Does quadriceps strength asymmetry is able to predict functional decline, gait abnormalities and falls in community-dwelling older adults? A cohort study

Abstract Introduction. Aging and articular degenerative inflammatory diseases, such as osteoarthritis, decline quadriceps strength. The reduction on quadriceps strength usually is asymmetric, and it may leads to an inefficient pattern to absolve ground reaction forces on the weaker limb during walking. Objective. The present study aimed to identify the ability quadriceps strength asymmetry to predict gait abnormalities, functional decline and falls prevalence in community-dwelling older adults. Methods. Participated of this study 52 older adults who live on a community-dwelling setting. The participants were separated into two groups according having or not knee extensor muscles strength asymmetry. Strength asymmetry was considered when the difference of strength between right and left maximal quadriceps maximal strength is higher than 20%. Twenty-four participants composed the strength asymmetry group and twenty-eight participants composed the control group. For the data collection: participants answered a characterization form; performed Short Physical Performance Battery and 400-m walking tests; three maximal isometric voluntary knee extensors contraction of right and left legs were recorded; and gait kinematics data was collected. The follow-up of the study was conducted after six months. A multivariate analysis of variance was used to compare the parameters, stepwise test was used to identify the predictive parameters and a ROC curve was used to determine the sensitive and specificity. The significant level was set at p < 0.05. Results. The quadriceps strength asymmetry was 28.9% in the group with strength asymmetry and the control group have 15% of quadriceps asymmetry. A strength asymmetry of 25% was able to predict functional a decline on the 400-m walking test (sensitivity = 78% and specificity = 82%); falls prevalence (sensitivity = 76,9% and specificity = 96,1%); and gait abnormalities, such as increased stance and stride time variability (sensitivity = 68% and specificity = 80%; and sensitivity = 71% and specificity = 84%, respectively). Conclusion. Quadriceps strength asymmetry higher than 25% may predict falls prevalence in community-dwelling older adults. Also, the quadriceps strength asymmetry predicts a functional decline, and temporal and spatial gait abnormalities those could reduce gait performance, promote early fatigue, and increase the risk of falls in older adults.