Serum cartilage oligomeric matrix protein accumulation decreases significantly after 12 weeks of running but not swimming and cycling training - a randomised controlled trial.

BACKGROUND: Acute effects of physical exercise on the deformational behaviour of articular cartilage and changes in cartilage oligomeric matrix protein (COMP) are definite. However, conclusive positive effects of fitness exercise on functional adaptation of articular cartilage have not been proved. AIM: Therefore, in this parallel-group randomised controlled trial, we tested the hypothesis that adequate amount of physical exercise with enough impact would be able to stimulate the functional behaviour of articular cartilage. METHODS: We evaluated 44 healthy males for their physical-fitness levels and their blood samples were obtained before, immediately after and 0.5h after a 30-min walking exercise. Thereafter, participants were assigned to the running, the cycling, the swimming and the control groups. At the end of 12weeks of intervention, the same measurement procedures were applied. Mixed repeated-measures analysis of variance (ANOVA) design was used for statistics. ( LEVEL OF EVIDENCE: 2). RESULTS: Pre-test measurements showed that 30min of walking significantly increased serum-COMP levels in all groups. The post-tests revealed that the COMP level of all groups, except running, showed an increase after a 30-min walking activity. CONCLUSION: Overall, it was concluded that, 12weeks of regular, weight-bearing, high-impact physical exercise (i.e., running) decreases the deformational effect of walking activity. This finding is an evidence of functional adaptation of articular cartilage to specific environmental requirements.

The effect of hip rotation on bone mineral density of the proximal femur measured by dual energy X-ray absorptiometry.

OBJECTIVES: The aim of this study was to compare the effect of lower extremity position changes on hip bone mineral density measured by dual energy X-ray absorptiometry. PATIENTS AND METHODS: Sixty-nine healthy university students (30 men, 39 women; mean age 21.9+/-1.6; range 20 to 25 years) participated in this study. Participants were evaluated in two groups as male and female. A special positioning device was produced and used during bone mineral density measurements. Measurements were performed in positions of external 30 degrees , external 15 degrees , neutral 0 degrees , internal 15 degrees , and internal 30 degrees of hip rotations. Measurements were evaluated at shaft, wards and trochanteric region of proximal femur. Differences between positions at shaft, wards, trochanter and total values were compared using repeated measures of analysis of variance. RESULTS: External rotation significantly increased bone mineral density values measured by dual energy X-ray absorptiometry in both male and female. The lowest bone mineral density value was measured at 30 degrees internal rotation in both sexes. There were slight differences between neutral, 15 degrees and 30 degrees internal rotation positions, but these differences were not statistically significant. CONCLUSION: Our findings suggest that position differences are important in adult healthy male and female during bone mineral density measurements of proximal femur using dual energy X-ray absorptiometry.

Comparison of landing maneuvers between male and female college volleyball players.

OBJECTIVE: To compare differences in kinematic and kinetic parameters of knee, hip and ankle joints between male and female college volleyball players. DESIGN: Cross-sectional study. BACKGROUND: Landing injuries, which usually involve anterior cruciate ligament injuries, are common in volleyball with a higher incidence in females. Landing preferences of both male and female players may provide additional background about the mechanisms contributing to the anterior cruciate ligament injuries. METHODS: Eight female and eight male college volleyball players performed spike and block landings from 40 and 60 cm height platforms. Lower extremity joint kinetics and kinematics, and leg muscle strengths were recorded. RESULTS: Females demonstrated significantly lower knee and hip flexion angles compared to their male counterparts in knee flexion at 40 cm spike and hip flexion at 40 cm block landings. Group comparison also revealed that male players' peak knee extensor moment at 60 cm block landing was significantly different than female players. Additionally, female players applied significantly higher normalized ground reaction forces and males knee flexion angles and thigh muscle strength results positive and highly correlated but relation could not found in females. It is likely that females may not use their thigh muscles as effective as males in landing. CONCLUSION: Female volleyball players initiate different lower extremity mechanics during landings than that of males. RELEVANCE: Identifying the landing strategy differences between female and male college volleyball players may provide detailed perspective about the load distribution in lower extremity joints for determining major factors affecting the increased incidence of anterior cruciate ligament injuries in females.