In the field of exercise science, it is well-known that weight-bearing activity builds stronger bones. Yes, milk and supplements can help, but the body responds best to weight-bearing activities such as weightlifting.
Your bones behave similarly to muscles. Lift weights consistently, and muscles grow. If you bear a lot of weight on bones, they grow stronger over time. The body is always paying attention to what you are doing. Banging out 100 squats is a very stressful event for the thigh and shin bones. Doing too much of that can risk a small fracture. In response to a stressful event such as squats, the body activates the chemical processes to build more bone to prevent fractures. Your bones are porous, like a sponge. They’re filled with tiny holes. A heavy set of squats sends the message to the body to fill more of those holes. Do that consistently over time, and voila! Denser, stronger bones.
Having strong bones is essential to health. Dense bone has a lower likelihood of fractures and reduces the possibility of osteoporosis at later ages.
Women are at particular risk for weaker bones or low bone mineral density. One in two women over the age of 50 will suffer a fracture due to osteoporosis. This can mostly be blamed on a long history of menstrual cycles and hormonal fluctuations. Unfortunately, this is why stress fractures are more common in women’s sports. And no sport has a higher incidence of bone injuries than cross-country or other distance running athletes.
Researchers at Towson University conducted an extensive research study on hundreds of their female athletes. They studied the body compositions of basketball, gymnastics, cross-country, field hockey, softball, and swimming and diving teams.
Across the board, the cross country athletes had the least muscle mass and fat mass. Cross country also had the lowest bone mineral density in the arms and trunk and the second-lowest density in the legs, ahead of swimming in the conducted study. Such low density in the legs can be surprising since running is all about landing and pushing off the ground.
Cross Country’s Bone Problem
Other studies show that male cross country runners also have lower bone mineral
density compared to other athletes, yet females have the lowest numbers. Research shows that up to one-third of female cross country runners could have osteopenia in the spine, a mild form of osteoporosis.
The exact reason why runners have lower bone mineral density isn’t fully known, but the answer is probably a combination of issues.
- First, runners run, a LOT! They run so much that the bones, muscles, and tendons do not get sufficient rest to recover properly.
- All that running leaves little to no time for other activities like weightlifting. Lifting weights is THE most superior method of building bone density.
- Calories. Runners tend to be thin. In our referred study, collegiate distance runners have the least amount of muscle, fat, and bone weight. That makes for a lighter person. Lighter is better when you want to run fast. However, staying light means low nutrition, which may reduce the ability to recover from training.
- Supplements. Another study shows that 8 in 10 runners take at least one supplement per day, and roughly 1 in 2 runners takes three or more per day. Some supplements may benefit the runners. Others may not. However, there could be an overreliance on supplements if the athletes aren’t getting proper nutrition. Nutrients from real food are always better and more absorbable than supplements. Overuse and reliance on supplements may be doing more harm than good.
- For female runners, the menstrual cycle contributes to bone mineral losses. During that time of the month, the body produces a hormone called relaxin, which causes the ligaments in the body to relax and loosen. This can increase the burden and stress on the bones, causing them to be prone to leak calcium into the bloodstream.
Although running entails a lot of load-bearing activity, it is a very heavy impact activity with an extremely high repetition volume. Weightlifting demands a lot of load for a long time on the ground. That’s proven to be most effective for building bone. Running is the exact opposite. It entails a quick, light impact. Running doesn’t appear to be an effective method to build bone strength. Over time, the constant high-impact repetition with little recovery leads to low bone density. It poses an increased risk for stress fractures.
One in two female collegiate cross country runners will suffer a bone stress injury in
their careers. How can we fix such high injury rates? We start combating the contributing factors.
- Lift weights. Runners don’t need to be brutally strong but stronger than the average person. Running doesn’t develop much strength. More muscle means less stress on the bones, and lifting will build denser bones. It’s a win-win.
- Better nutrition. To support a more muscular frame, athletes need more calories. This will help speed up recovery processes and maintain their strength to bodyweight ratio, which is so crucial to efficient running.
- Better recovery practices. This is a loaded one. Lifting weights and better nutrition habits will speed up recovery rates. However, they still may not be enough to prevent overtraining. The simplest method is to train less. That may be the best strategy. Other considerations are reducing the training during the menstrual cycle, as that is when the athlete is particularly vulnerable. Tapering, rehab exercises, and modalities such as ice and compression sleeves can also enhance recovery.
Practicing these good habits will reduce the current incidence of pain and injuries such as shin splints and stress fractures for female athletes. Further, it will reduce the likelihood of osteoporosis later in life.
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