Osteogenic effect of endurance cycling /

Abstract

The purpose of this dissertation was to determine a potential cause of low bone mineral density (BMD) in male cyclists and to test a novel treatment. Two studies were performed. The aim of the first study was to determine whether cortisol levels at the start or finish of a cycling competition were related to lumbar spine and hip BMD in road cyclists. A secondary aim of the first study was to determine factors associated with BMD in male cyclists. The sample included 35 male cyclists with a mean age of 43 years. Salivary cortisol was not correlated with BMD of the lumbar spine or hip. Cyclists who reported a higher number of minutes of weekly participation in weight lifting had higher BMD of the lumbar spine, total hip, femoral neck, and femoral trochanter. Cyclists with higher daily calcium intake had higher BMD of the lumbar spine and femoral neck. Cyclists with a greater number of years of experience had lower femoral neck BMD.

The aim of the second study was to administer calcium with vitamin D supplementation during training and racing in male cyclists in order to maintain and/or improve BMD across a 5-month competitive season. The sample concluded with 17 participating male cyclists with a mean age of 43 years. There were indicated no significant differences between the calcium supplement group and the control group. There was a significant decrease in femoral trochanter BMD across the competitive season (May to October) in the full sample.

Osteopenia was prevalent in these samples. It was found that half of the cyclists were considered at risk for fracture in the lumbar spine or hip in study one of this dissertation. Further, in the second study, 71% ( n = 12) of the cyclists were at risk for fracture in the lumbar spine or hip at the 5-month follow-up. Taken together, these findings suggest the importance of encouraging endurance cyclists to maintain a calcium-rich diet to help improve or maintain BMD. It is also important that cyclists include a weight training regimen to strengthen bones.