The Effect of Mechanical Loading During Sports Exercises on Degradation of Human Articular Cartilage

Design

A prospective, parallel-group randomized control trial was designed. Mustafa Kemal University (MKU) Ethical Board approved the study (B.30.2.MKU.0.01.01.00/255). The exact nature of the study was explained to participants and they were asked to sign a written consent. The tests were carried out at Middle East Technical University Medical Center, Ankara, Turkey between January and June 2008. The independent variables were groups (n=4) and time (n=2). The dependent variable was serum cartilage oligomeric matrix protein (COMP) levels measured at three phases of exercise: before (Recovery), immediately after (Fatigue), and 30-min after the exercise (Regeneration). Participants were subjected to the following tests prior to and at the end of the intervention period: body mass index (BMI), isokinetic leg muscle strength, maximum oxygen consumption (VO2max) and serum COMP levels.

Participants

115 applicants volunteered to take part in this study. Eligibility screening was performed according to inclusion criteria. From 104 eligible applicants, 48 healthy, sedentary male university students aged between 18 to 25 years old (Mage = 21.8±1.9) were selected by a simple drawing. However, study completed with 44 participants, because of 4 dropouts. Participants were randomly assigned in 1:1:1:1 ratio to parallel groups, three exercise groups (swimming, cycling and running) and one control. In order to have a random allocation, each participant received a number unknown to researchers which was written on a piece of paper and then drawn from a box that allowed to assign individuals to the control and exercise groups. Baseline blood samples were stored in -80°C and they were not analyzed during participants' allocation. Exclusion criteria, surveyed by a questionnaire, were: osteoarthritis, rheumatoid arthritis or other inflammatory joint disease, intra-articular steroid injection, mal-alignment of the knees (varus/valgus) larger than 15°, and recent (within six months) fracture of lower extremity. Active athletes and volunteers with previous sports background were not included. During the intervention period, one participant was excluded from the study because of sudden kidney disease and another one decided to withdraw from further participation. In addition, two participants were excluded from the study before biochemical analyses since one subject from running group didn't meet minimum requirement of 75% of exercise session attendance, and one subject from control group didn't complete the posttests. Descriptive data of participants are presented in.

Interventions