Cycling and Bone Health
Should we be concerned about spending too much time on the bike saddle? As an avid cyclist and a physician interested in successful aging, I have followed the literature on bone health in cyclists. Adult bone mineral density is dependent on many factors including genetics, nutrition, weight bearing exercise and other lifestyle factors. One of the key determinants to bone health as you age is the peak bone mass achieved during adolescent years. This has led to the description of Osteoporosis as a disease of adolescence, not aging.
Higher impact exercise leads to greater peak bone mass and in general, young athletes have greater bone density than their non-athletic counterparts. However, there is a concern for younger endurance athletes, including cyclists. There are several suggested etiologies for lower bone density in endurance athletes: genetics, nutritional errors or energy imbalances, training-related suppression of sex hormones, exertional loss of calcium and lack of sufficient mechanical stressors.
Related to the issue of the male endurance athlete, our Human Performance lab at Colorado Mesa University recently looked at the bone status using Quantitative Ultrasound (QUS) of 50 collegiate athletes from five sports. There was significant difference in the stiffness index of bone between cycling and all weight bearing sports (soccer, football, cross-country) as noted in the figure below.
Figure. Comparison of stiffness index (SI) values between dominate foot for each sport. There was significant difference (p < 0.01) between all sports and cycling. Error bars indicate standard error. Each group listed in the graph consisted of 10 currently participating collegiate athletes from Colorado Mesa University.
As health care providers or concerned parents, this information leads to several recommendations:
1. Avoid sports specialization in the young athletes
a. Including activities with weight bearing and multidirectional movement is key
2. Optimize nutrition – the Institute of Medicine recommends that adolescent athletes consume 1300 mg of calcium and 600 IU of Vitamin D daily. Achieving this through a balanced and varied diet would be ideal but the supplementation of Vitamin D may need to be considered.
3. Maintain a positive energy balance to support musculoskeletal health.
4. Consider screening for impaired bone health.
a. Risk Factors per Barrack et al (2017):
i. Low body weight
ii. History of stress fractures
iii. High weekly mileage
iv. Consuming fewer than one serving of calcium containing foods per day
Although the overall effect of exercise is so positive, it is important to consider bone health in the adolescent and collegiate aged athletes in our roles as coaches, parents and health care providers.
Dr. Mike Reeder, Monfort Family Human Performance Lab, Colorado Mesa University
Barrack MT, Fredericson M, Tenforde AS, et al. Evidence of a cumulative effect of risk factors predicting lower bone mass among male adolescent athletes. BJSM 2017 (in press)
Tenforde AS, Nattiv A, Ackerman K, et al. Optimizing bone health in the young male athlete, BJSM, 2016.
Beatty T et al. Bone density in competitive cyclists. Current Sports Medicine Reports, 2010.