People’s bones have tended to become less dense as they get older, leading to increased risk of fractures. Having low bone mineral density puts you at high risk for fractures, including severely debilitating hip fractures. About 250,000 people break their hips every year in the US. This costs billions in health care and can result loss of mobility, bone necrosis (decay of the tissue), lots of pain and suffering and sometimes, death. Hip fractures can be extremely difficult to heal because bone breaks can result in loss of blood supply to sections of bone. Luckily bone density is something over which we have some control. There are several things that are important: diet, vitamin D, and weight-bearing exercise. They are important as a threesome.
Most of us are probably aware that weight-bearing exercise helps build bone. Weight stresses bones. Bone responds by getting thicker, stronger and more dense. It needs calcium to do this. If there is not enough calcium in circulation, your body will take calcium from bones that are not under particular stress and stick it where it thinks it needs it. This means you can build your femurs while weakening your wrists. Strengthening hip bones is important because the consequences of hip fracture can be devastating, but it is important to keep the whole picture in mind. Whole body workouts, along with a good diet, are best.
How much weight-bearing exercise do I need?
Research indicates one hour of weight bearing exercise three times a week is enough to prevent bone loss. This doesn’t mean that this is the ideal amount. It just means that it produced measurable results. More might be better. Less might be OK. But one hour, three times a week, works!
What type of weight-bearing exercise is best?
The aim is to put mechanical stress on your bones without causing injury. This can take any number of different forms. A major study used very basic lower body exercises, including jumping, with a weighted vest. Participants started out slowly, adding weight as they went along, with weights tailored to each individual. Participants were all older women described as “active and not sedentary”. They did lunges, lateral lunges, chair raises, stepping, and jumping down from an 8-inch step in a group exercise class. Vest weights were increased incrementally over the course of the study. The women were followed for five years, which is terrific. It is really hard to do these kinds of studies without losing people to moves, injuries, etc. A control group was instructed to refrain from new exercise, but to otherwise carry on life as they normally did. Measures of bone density were made at the beginning of the study and five years later.
Women who participated in the weighted vest exercise program increased bone density by about 1%. That may not seem like much until you look at the results from the women who did not do the weighted vest exercise. The control women, who were also described as active and not-sedentary) had about a 4% loss of bone mineral density. The extra weighted vest exercise prevented what used to be considered an inevitable part of growing older.
What I found particularly interesting was the amount of emphasis placed on jumping as a means of stressing bone. Jumping has been shown to produce measurable results in young women in as little as two weeks. (Kishimoto et al. 2012). Maybe we should be grateful for box jumps and burpees, instead of hating them, like I do. If you are someone who steps up as an alternative to jumping up on box jumps, consider stepping up and then jumping down. The landing will stress your hips and leg bones and help strengthen them. Jumping down may actually be more productive, in terms to increasing bone strength, than the trip up.
A note about rowing: rowing helps build bone in the spine. This is important too. Remember whole body training and care.
Here is a short video for those who want to learn more about hip fractures. I found this video series very helpful in medical school. There is something soothing about them too.
Shaw JM, & Snow CM (1998). Weighted vest exercise improves indices of fall risk in older women. The journals of gerontology. Series A, Biological sciences and medical sciences, 53 (1) PMID: 9467434
McNamara, A., Gunter, K., & Snow, C. (2005). Postmenopausal Women Who Participate In Rowing Exercise Have Higher Spine BMD Than Controls Medicine & Science in Sports & Exercise, 37 (Supplement) DOI: 10.1249/00005768-200505001-00815