Abstract
Aim: To investigate the correlation of lower-limb muscle function with clinical status, balance, and quality of life in individuals with Parkinson disease (PD).
Methods: Twenty-five participants were included. Outcome measures were assessed through scales and questionnaires. Quadriceps muscle function was assessed through a maximal isometric voluntary contraction. Spearman's correlation coefficient ([rho]) analysis was performed.
Results: Quadriceps peak force was negatively correlated with scores of the Unified Parkinson's Disease Rating Scale (UPDRS) part III ([rho]= 0.610) but positively correlated with scores of the Mini-BESTest ([rho]= 0.484) and the Timed Up and Go test ([rho]= 0.528). The rate of force development was negatively correlated with scores of the UPDRS II ([rho]=-0.437) and III ([rho]=-0.577). Force variability was positively correlated with the quality of life (Parkinson's Disease Questionnaire 39; [rho]= 0.455).
Conclusion: Better quadriceps muscle function is associated with better clinical status, balance, and quality of life in people with PD.