Low bone mineral density in highly trained male master cyclists

Abstract

The purpose of this study was to determine total and regional bone mineral density (BMD) in highly competitive young adult and master male cyclists. Three groups of men were studied: older cyclists (51.2+/-5.3 years, n=27); young adult cyclists (31.7+/-3.5 years, n=16); and 24 non-athletes matched by age (+/-2 years) and body weight (+/-2 kg) to the master cyclists. All of the master cyclists had been training and racing for a minimum of 10 years (mean 20.2+/-8.4 years) and engaging in little to no weight-bearing exercise. The younger cyclists also engaged in little weight-bearing exercise and had been training and racing for 10.9+/-3.2 years. Age-matched controls were normally active. The History of Leisure Activity Questionnaire was used to determine the influence on BMD of self-reported total and weight-bearing exercise during three periods of life: 12-18 years, 19-34 years, and 35-49 years. BMD (measured by DXA) of the spine (L2-L4) and total hip was significantly (P<0.033) lower in the master cyclists compared to both age-matched controls and young adult cyclists. Total body BMD was lower in the master cyclists compared to the young-adults (P<0.033). Furthermore, four (15%) of the master cyclists, but none of the men in the other groups, had T-scores (spine and/or hip) lower than -2.5. Weight-bearing exercise performed during teen and young adult years did not appear to influence BMD, as there were no differences at any site between those within the upper and lower 50th percentiles for weight-bearing exercise during the 12-18, 19-34, or 35-49 year time periods. These data indicate that master cyclists with a long history of training exclusively in cycling have low BMD compared to their age-matched peers. Although highly trained and physically fit, these athletes may be at high risk for developing osteoporosis with advancing age.

Bone Loss Over 1 Year of Training and Competition in Female Cyclists

“…Studies have been predominantly cross-sectional comparisons of male cyclists with other groups of athletes or non-athletes. In such studies, proximal femur and lumbar spine aBMD have been 3.3% to 17.7% lower in road cyclists than in age-matched runners or untrained controls 7,8,10,11,13 , despite cyclists having greater lean mass in some studies 7,10,11 . Differences persisted when adjusted for lower body mass 8 .…”

“…Differences in aBMD and BMC between cyclists and controls aged 17-21 years were larger than the differences between cyclists and controls under 17 years of age 12 . Master cyclists have also been found to have lower hip and spine aBMD values than young adult cyclists or age-matched controls 11 . Studies with longer follow-up are needed to determine if these observations reflect a progressive decline in aBMD in cyclists that exceeds the expected age-related decline 30 .…”

Ground reaction forces and osteogenic index of the sport of cyclocross

“…The downhill run-up sequence demanded the greatest number of loading cycles, and also yielded the largest OI calculation. While there are obvious cardiovascular and metabolic health benefits associated with exercise, research has shown that bone mineral density of endurance athletes may be jeopardised due to lack of weight-bearing activity (Duncan et al, 2002; Nichols et al, 2003; Rector et al, 2008; Stewart & Hannan, 2000). In contrast to road cycling, cyclocross incorporates bouts of running and jumping while pushing or carrying a bicycle, in addition to pedalling on uneven terrain; these activities may induce external gravitational loads that benefit skeletal health.…”

“…The positive correlation between weight-bearing activities and bone mineral density may be partly attributable to mechanical stress imparted on the skeleton during ground impacts absent in non-weight-bearing sports (Kohrt et al, 2004). There is evidence that endurance athletes such as road cyclists exhibit significantly lower bone mineral density in the spine and hip compared to non-athletes; therefore there is concern that the biomechanics of road cycling may not adequately stimulate bone formation (Burnfield, Jorde, Augustin, Augustin, & Bashford, 2007; Nichols, Palmer, & Levy, 2003; Nichols & Rauh, 2011; Stewart & Hannan, 2000). Warner et al’s study comparing competitive male mountain bikers and road cyclists revealed significantly higher bone mineral density in mountain bikers (Warner, Shaw, & Dalsky, 2002).…”

Dairy-Based Preexercise Meal Does Not Affect Gut Comfort or Time-Trial Performance in Female Cyclists

“…These guidelines focus on bone health, where dairy foods are identified as a unique source of well-absorbed calcium. Low bone mineral density is prevalent in both male (Barry & Kohrt, 2008;Campion et al, 2010;Lombardi et al, 2012;Medelli et al, 2009;Nichols et al, 2003;Olmedillas et al, 2011;Rector et al, 2008) and female cyclists (Sherk et al, 2013), possibly owing to the absence of load-bearing exercise (Milgrom et al, 2000) and low energy availability (Barry & Kohrt, 2008;Loucks et al, 2011).…”