How heavy is too heavy for lifting weights? Can you increase bone density with light weights? These are just some of the questions people are constantly asking about training for bone health and treating osteoporosis.
We have written on this matter many times, but this time, we decided to just ask Dr. Belinda Beck. Dr. Beck was the lead researcher in the LiftMor study, head of The Bone Clinic, and began the ONERO Academy. Here’s what she had to say.
Key Points You Need To Know!
The LIFTMOR study was a 2018 landmark study on resistance training and bone health.
Researchers found heavy loads of 80-85%1RM were vastly superior for increasing bone strength.
In addition, these heavy loads resulted in greater improvements in stature, functional capacity, and muscle strength.
Dr. Belinda Beck was the head researcher and reaffirms her belief in heavy strength training.
What Is The LiftMor Study?
Quick review on The LIFTMOR study. This was a 2018 landmark research project that examined the effect that strength training with heavy loads had on bone mineral density (BMD) (Watson et al., 2018).
The major findings were:
Heavy Loads of 80-85% 1RM were safe
Compound barbell exercises like the deadlift were safe
Strength training improved numerous health markers
Bone mineral density (BMD)
Functional performance
Stature
Bone Health
This had a massive effect on how strength training can be used in clinical settings to improve the health of lifters.
However, there’s still pushback and criticism of using heavy loads. This is why we think it’s important to spread the work of Dr. Belinda Beck, head researcher of this study.
5 Questions With Dr. Belinda Beck On Training For Bone Health
Back in May 2026, we asked Dr. Belinda Beck a quick 5 questions regarding strength training for bone health. She was more than happy to share her thoughts, and we greatly appreciate her insight!
In fact, we wish we had asked more! But here are the 5 questions and answers as is, and then we’ll give some final thoughts after.
1. What is the ideal load for BMD? Obviously, there’s nuance, but setting all that aside, you seem to like 85%1RM.
Until a side-by-side trial is done of all the different loading possibilities, it’s not possible to know for sure. That trial would require very big numbers (we are talking 10s of 1000s – IKR!), so it is unlikely to ever be funded even if some poor soul did have the energy.
In the absence of definitive data, we have to look historically. There, we see how disappointing trials that applied low to moderate intensity loading are for bone gains. LIFTMOR applied 85% 1RM intensity and observed results that outstripped those from more moderate studies, so we can infer it is a more effective stimulus.
The critics will say more frail people will improve with lower loads…which is true…but absolute load is not the metric. The same 2 loads will be a different % of different people’s capacity. Obviously.
The most exciting data is coming out of my research clinic – The Bone Clinic. We have been open for nearly 11 years now, and I have some fantastic data clearly showing a dose response to loading. I am hoping to publish this exciting data over the next year.
Long story short, I am very comfortable sticking to my guns that heavy lifting (as a % of a person’s capacity) is the way to increase bone mass in people at risk of OP fx.
(We break down the LIFTMOR study here for deeper insight!)
2. Is there a threshold that must be met for load to benefit BMD? I.e. 50% 1RM? 70% 1RM? Many comments will suggest >85%1RM might be better, but lighter weight still works. How true is this, and to what extent?
Light lifting will not grow bone. This is coming from people attempting to carve out a niche for themselves who do not fully understand the historical experimental animal work that has been done in this area.
3. In the LiftMOR study, your team mentions the prevalence of underdosing:
“The limiting feature of high-intensity resistance training in this demographic has traditionally been the perceived increased risk of fracturing fragile bone with heavy loading. We believe this overly conservative approach has contributed to an unnecessary stagnation in the field”.
Could you expand on this a little more? Is underdosing due to fear of lifting? Is inaccurate or outdated material being taught in the industry? Why is there so much pushback against heavy lifting?
Fear of fracture. This is the catch-22 of HiRIT in an OP demographic.
(We have a full article on this topic here!)
4. Your LiftMOR and Medx-OP studies showed similar adherence and injury rates to the low-intensity group, yet saw tremendous benefits: BMD, strength/functional increases, improved stature, fractures, etc. – What are you doing or think can be done to change the mindset of those in the industry?
Depends what industry you mean – gym set or doctors. The answers are different for each, but I am currently changing it to one client and one ONERO licensee at a time.
5. I was hoping you could comment on my idea. Bone remodeling occurs through loading and strain – So, if I were to provide variables for training, would I be correct in suggesting you don’t need to approach failure? For example, if I were to use a load of 85%1RM, could I use sets of 2 reps instead of 5 reps?
Again, this is not known because the studies haven’t been done. I’m attaching a paper I wrote that will help answer this question.
FAQ: The LiftMor Study And Bone Health
1. What Is The Best Strength Training Load For Bone Density?
Current evidence suggests heavy resistance training may be the most effective stimulus for improving bone mineral density (BMD). Dr. Belinda Beck’s LIFTMOR study used loads around 85% of one-repetition maximum (1RM) and produced results that exceeded many lower-intensity interventions. While more research is needed, heavy loading remains one of the most promising strategies for bone health.
2. Does Lifting Light Weights Improve Bone Density?
Research suggests light resistance training is generally less effective for increasing bone mass than heavier loading. Bone responds to mechanical strain, and higher loads appear to create a stronger osteogenic stimulus. However, exercise selection, progression, and individual capacity still matter.
3. Do You Need To Lift To Failure For Bone Health?
Current research has not established that training to muscular failure is necessary for improving bone density. The primary factor appears to be sufficient mechanical loading rather than maximizing fatigue. More research is needed to determine the ideal combination of load, repetitions, and effort.
4. Why Is Heavy Resistance Training Recommended For Osteoporosis?
Heavy resistance training exposes bones to greater mechanical forces, which may help stimulate bone remodeling and adaptation. Studies such as LIFTMOR and MedX-OP found that properly supervised high-intensity training was both effective and well-tolerated in people at risk for osteoporosis. Fear of fracture has historically led to conservative exercise prescriptions.
5. Is Heavy Weight Training Safe For People With Osteoporosis?
When properly supervised and programmed, research suggests heavy resistance training can be performed safely by individuals with low bone density. Clinical trials have reported injury and adherence rates comparable to lower-intensity exercise groups. Proper technique, exercise selection, and progression remain essential.
6. What Exercises Are Best For Increasing Bone Density?
Compound exercises that place meaningful load through the skeleton are often recommended. Examples include deadlifts, squats, overhead presses, and other weight-bearing resistance exercises. The specific exercise matters less than applying sufficient load safely and progressively.
7. How Long Does It Take To Improve Bone Density With Strength Training?
Bone remodeling is a slow biological process, so measurable changes in bone density often take several months to appear. Most osteoporosis and bone health studies assess outcomes after 6 to 12 months of consistent training. Improvements in strength and physical function typically occur much sooner.
Final Thoughts
As you can see, there’s still research to be done on this topic, but one thing is clear: Dr. Belinda Beck strongly recommends using loads of 85% 1RM when training for bone health. In addition, while we didn’t ask in this interview, the LiftMor study used the deadlift.
This is yet another “issue” that has been making rounds on social media, yet it’s used in clinical settings with heavy loads safely! There has been a lot of scaremongering lately concerning gym training and lifting weights. While it’s always good to be aware, the reality is that not only can it be safe, in some cases, it can be the best option.
References
Watson, S. L., Weeks, B. K., Weis, L. J., Harding, A. T., Horan, S. A., & Beck, B. R. (2018). High-Intensity Resistance and Impact Training Improves Bone Mineral Density and Physical Function in Postmenopausal Women With Osteopenia and Osteoporosis: The LIFTMOR Randomized Controlled Trial. Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research, 33(2), 211–220. https://doi.org/10.1002/jbmr.3284
