Build Stronger Bones
No-one wants to break a hip, but the reality is nearly 300,000 Americans break a hip each year. While this number sounds scary, it only represents approximately 0.09% of the total U.S. population and this percentage is primarily made up of individuals over the age of 65.
Why does this happen?
From birth to our 30s our body is constantly laying down and rebuilding bone. Cells called osteoclast are breaking down old or damaged bone and cells called osteoblast come in and build new bone. It’s a constant well balanced cycle of breaking down old bone and building new bone. This leads to us having our strongest bones starting in our 20s and into our 40s.
However, as we age this well balanced cycle becomes unbalanced. The cells that break down the bone get more efficient at breaking down bone and the bone-building cells decrease their activity. This leads to an eventual loss of bone strength overtime that starts in our 40s-50s as you can see in the graph on the right. This loss of bone strength is also sped up due to the changes in our hormones. During menopause for women (primarily driven by the decrease in estrogen) and driven by the decrease in testosterone and estrogen in men.
However, this rapid bone loss and subsequent increase in risk of fracture isn't inevitable.
How We Can Maintain the Strength of Our Bones
Much like how we can make our muscles stronger and our heart more efficient we are also able to make our bones stronger. The reason for this is because our bones follow the same principles as our muscles - the principle of specificity - our body adapts to the demands we place on it (when we allow for proper recovery).
For our bones this means if our activity decreases - as it typically does as we age - we see a decrease in bone strength and an increase in risk of fracture. However, when we stay active we decrease our fracture risk and maintain the strength of our bones.
In fact a study that followed the activity of 61,200 women, aged 40 to 77 years over a twelve year period found that individuals who walked 8 hours a week had 55% reduction in hip fracture compared to those that walked less than an hour each week. The study also found.
6% reduction of hip fracture for each additional hour walked per week
41% reduction of hip fracture when walking 4+ hours vs <1 hour per week
55% reduction of hip fracture when walking 8+ hours vs being sedentary
Compared to not being active walking helps us maintain our bone strength and helps to reduce our fracture risk.
Is Walking Enough for Building Stronger Bones?
Just like we discussed in our recent post about getting out of breath going up the stairs, our bones follow the same fundamental principle - The Principle of Specificity.
Our bodies adapt to exactly what we ask them to do - no more, no less.
This means that while walking is fantastic for your overall health (and yes, it does help your bones), it might not be providing enough stimulus for optimal bone strength. Think about it this way: your bones are incredibly strong - they can withstand forces many times your body weight. So to make them stronger, you need to give them a reason to adapt.
Why Walking Isn't Enough
Walking provides what we call "low-impact" exercise it can help maintain bone density, especially in older adults. But here's the catch - while walking is beneficial, it might not provide enough stimulus for significant bone strengthening, particularly in individuals under 65. Activities like Yoga, Pilates, and Tai-Chi are other great low impact activities that have been shown to help maintain bone health but not necessarily increase it.
What actually builds bone strength?
To build stronger bones we have give our body a reason to create stronger bones to do this our bones respond best to:
Progressive loading: Gradually increasing the forces they need to handle(lifting weights).
Different directions of force: Not just up and down, but side-to-side and rotational movements
Impact activities: Activities that create ground reaction forces (skipping, jumping, running, power-cleans).
How You Can Build Stronger Bones
Don't worry - you don't need to become a competitive weightlifter or start jumping off boxes to build stronger bones. Here's how to build stronger bones while staying safe:
Keep walking, but add variety:
Include hills in your route
Pick up the pace occasionally
Try different terrains
Add resistance training:
Start with bodyweight exercises like squats and push-ups
Progress to using weights when ready
Focus on increasing weights, sets, reps and maintaining good form (progressive overload is key)
Strength training 2 times a week has been shown to be effective for increasing bone strength but 3 times a week has been shown to be more effective.
Include impact activities (if appropriate):
Step-ups
Controlled jumping (if your joints are healthy)
Dancing
Another Reason to Move
Walking is fantastic for your overall health, but for optimal bone strength, you need a bit more. By understanding the Principle of Specificity, you can make smart additions to your routine that will help build and maintain strong bones throughout your life.
Remember it's never too early or too late to start building bone strength. Your skeleton is constantly remodeling itself, ready to adapt to whatever challenges you give it. The key is to start where you are and progressively challenge yourself in safe, controlled ways.
References
Harding AT, Weeks BK, Lambert C, Watson SL, Weis LJ, Beck BR. A Comparison of Bone-Targeted Exercise Strategies to Reduce Fracture Risk in Middle-Aged and Older Men with Osteopenia and Osteoporosis: LIFTMOR-M Semi-Randomized Controlled Trial. J Bone Miner Res. 2020;35(8):1404-1414. doi:10.1002/jbmr.4008
Huovinen V, Ivaska KK, Kiviranta R, et al. Bone mineral density is increased after a 16-week resistance training intervention in elderly women with decreased muscle strength. Eur J Endocrinol. 2016;175(6):571-582. doi:10.1530/EJE-16-0521
Karinkanta, S., Kannus, P., Uusi-Rasi, K., Heinonen, A., & Sievänen, H. (2015). Combined resistance and balance-jumping exercise reduces older women's injurious falls and fractures: 5-year follow-up study. Age and ageing, 44(5), 784–789. https://doi.org/10.1093/ageing/afv064
Lee S, Kim JS, Park KS, Baek KW, Yoo JI. Daily Walking Accompanied with Intermittent Resistance Exercise Prevents Osteosarcopenia: A Large Cohort Study. J Bone Metab. 2022;29(4):255-263. doi:10.11005/jbm.2022.29.4.255
Shojaa M, Von Stengel S, Schoene D, Kohl M, Barone G, Bragonzoni L, Dallolio L, Marini S, Murphy MH, Stephenson A, Mänty M, Julin M, Risto T and Kemmler W (2020) Effect of Exercise Training on Bone Mineral Density in Post-menopausal Women: A Systematic Review and Meta-Analysis of Intervention Studies. Front. Physiol. 11:652. doi: 10.3389/fphys.2020.00652
Wang Z, Zan X, Li Y, Lu Y, Xia Y and Pan X (2023), Comparative efficacy different resistance training protocols on bone mineral density in postmenopausal women: A systematic review and network meta-analysis. Front. Physiol. 14:1105303.
doi: 10.3389/fphys.2023.1105303