Comparative Evaluation of Core and Knee Extensor Mechanism Muscle Activation Patterns in a Stair Stepping Task in Healthy Controls and Patellofemoral Pain Patients Journal title: Journal of Rehabilitation Sciences and Research Authors: Alireza Motealleh, Nader Maroufi, Javad Sarrafzadeh, Mohammad Ali Sanjari, Nasrin Salehi Subject(s):