SUBJECTS AND METHODS
In this single randomized controlled trial study, the participants were selected through a simple non-probability sampling method and were randomly divided into two equal groups using sequences of random numbers. The first group (n=15) performed stabilization exercises, and the second group (n=15) performed McKenzie exercises. The examiner who assessed the outcomes was blinded to group assignment. The training program consisted of 18 sessions of supervised individual training for both groups, with the sessions performed 3 times per week for 6 weeks. Each training session lasted an hour and was performed at the Physiotherapy Clinic in the School of Rehabilitation, Tehran University of Medical ciences, Tehran, Iran, between 2011 and 2012. Outcomes were measured in both groups before and after treatments. The study protocol was approved by the ethics committee of Tehran University of Medical Sciences. All patients provided written informed consent to participate in the study.