Does Reformer Jumping “Count” for Bone Health?

Why less impact does not mean no benefit—and why the honest answer is more nuanced than social media suggests

You may have heard that jumping is good for your bones. You may also have heard that jumping on a Pilates Reformer does not “count” because you are lying down rather than landing upright with your full bodyweight.

There is some truth inside that argument: upright jumping has been studied far more extensively, and the forces created during a standing landing are not the same as those created on a spring-loaded moving carriage.

But that does not make Reformer jumping meaningless. And it certainly does not mean that a person who cannot—or simply does not—jump while standing receives no useful physical stimulus from a jumpboard.

The better question is not, “Does it count?”

It is: What does this version of jumping train, what do we know about its effect on bone, and what should come next for this particular body?

Bone responds to loading, not simply movement

Bone is living tissue. It adapts to mechanical loading, but the signal is more complicated than one force number. The magnitude of the strain, how quickly it is applied, its direction, how novel it is and how often it is repeated can all influence the response. Muscular contractions also contribute to the forces experienced by bone.

Research supports the importance of loading rate. In an experimental study that applied the same peak strain to bone at different rates, faster strain rates produced more bone formation than slower rates.[1] That does not give us a formula for a human Pilates session, but it helps explain why rapid force production may offer something different from another slow repetition of footwork.

This is where the often-repeated claim that bone requires “three times bodyweight” becomes misleading.

One frequently cited trial asked women to perform 50 vertical jumps six days per week. The younger women produced average ground-reaction forces of approximately three times bodyweight and increased femoral bone mineral density. The postmenopausal women produced approximately four times bodyweight, yet did not show a significant bone-density benefit.[2]

In other words, that study did not establish three times bodyweight as a universal threshold. In fact, its results demonstrate why a single force multiple cannot predict who will build bone.

What is different on the jumpboard?

During a standing jump, the body accelerates against gravity and then lands on a stationary surface. The resulting force travels through the feet and lower extremities while the person supports their body upright.

On the Reformer, the carriage supports the body against gravity. The feet press into the jumpboard while the carriage moves horizontally against spring resistance. The footplate still returns a reaction force to the feet—the interaction does not become force-free because the person is lying down—but its direction, magnitude and distribution are different from those of an upright landing.

Spring choice, spring extension, carriage and participant mass, carriage velocity, jump technique and landing strategy will all affect the forces involved. Because these variables have not been adequately measured in published jumpboard research, we cannot honestly assign a bodyweight multiple to a Reformer jump or claim that it delivers the same skeletal stimulus as standing impact.

We also cannot honestly conclude that it delivers none.

What Reformer jumping can train

For a person who otherwise performs no jumping, well-programmed jumpboard work can introduce several valuable capacities:

● producing force quickly enough to leave the board

● coordinating the ankle, knee and hip during takeoff

● accepting and decelerating force during landing

● repeating faster lower-extremity loading

● developing lower-body power and muscular endurance

● building confidence with flight and landing

Those qualities matter. Power—the ability to produce force quickly—is important for climbing stairs, recovering from a misstep and getting the body where it needs to go before a fall occurs. Landing practice also gives us an opportunity to work on alignment and force absorption with substantially more support than a standing jump provides.

Progressive jumping exercise has improved leg-extensor power, dynamic balance and cardiovascular fitness in postmenopausal women even in a trial where it did not significantly change lumbar-spine or femoral-neck BMD.[3]

That distinction matters: an exercise can be valuable for function and fall-risk reduction without our needing to market it as a proven bone-building intervention.

Do lighter springs make the exercise more useful?

More spring is not automatically better.

Heavier springs increase resistance, but they can also turn an intended jump into slower, heavily resisted leg work. An appropriately lighter setting may allow the participant to accelerate the carriage, produce an actual moment of flight and practice a responsive landing. The appropriate setting is the one that preserves control while still asking the person to push with intent.

That is not the same as saying that the lightest spring creates the greatest bone stimulus. We do not have the measurements needed to make that claim. It means spring selection should match the training objective: strength, velocity, landing skill, endurance or some combination of them.

What about holding five-pound weights?

Two five-pound hand weights add some mass to the moving system and can increase whole-body effort. If the arms move dynamically, they can also add an upper-body power and coordination challenge.

But the carriage still supports those weights against gravity. Holding ten additional pounds while supine does not reproduce wearing ten pounds while landing upright, nor can we assume that it substantially increases the osteogenic load reaching the hip or spine. No research currently tells us that adding hand weights to jumpboard work changes its bone-density effect.

Use the weights because they serve a clear programming goal—not to manufacture an unsupported bone-health claim.

Supported jumping can be a destination and a bridge

Upright impact and progressive resistance training have the stronger evidence for improving or preserving bone at clinically important sites. For example, the supervised LIFTMOR trial combined high-intensity resistance exercise with impact training in postmenopausal women with low bone mass. After eight months, the intervention group had better lumbar-spine and femoral-neck BMD outcomes than the low-intensity comparison group.[4]

Longer-term research has also found that a program combining weighted vests with upright jumping helped postmenopausal women maintain hip BMD over five years.[5] These findings support progressively challenging the body when that challenge is appropriate and well supervised.

But not every person begins there. Some adults have never jumped. Some are afraid to try. Others lack the strength, balance, foot tolerance or confidence to land safely while standing. Some may not be appropriate candidates for upright jumping at all.

Interestingly, researchers have even reported improved BMD and functional fitness following a 24-week high-intensity aquatic jumping program in postmenopausal women.[6] That study did not test the Reformer, and we should not pretend that it did. It does, however, reinforce the broader point that reduced-weight-bearing environments do not make vigorous muscular and mechanical loading automatically irrelevant.

For the right person, the jumpboard can therefore be both a meaningful training environment and a bridge toward greater loading. Progress might eventually include faster sit-to-stands, heel drops, step-ups, loaded carries, heavier resistance training, supported standing hops or upright jumps. It might also remain on the Reformer while the person develops power in a form they can perform confidently and consistently.

The honest conclusion

We do not currently have clinical evidence showing that Reformer jumpboard exercise alone increases bone mineral density. We should not promise that it does or describe it as equivalent to upright impact.

We should be equally cautious about declaring that it “does not count.” The jumpboard supplies resistance and reaction force, asks the muscles to produce and absorb force rapidly, and can make jumping accessible to someone who would otherwise receive none of that exposure.

Bone health programming is not an argument between Pilates and standing jumps. A complete approach may include progressive resistance training, balance work, weight-bearing activity and appropriately selected impact. The proportions depend on the person in front of us.

If you are ready to turn thoughtful programming into a stronger, more adaptable practice, try BaseBuilder—a practical resource for building progressive movement plans around the person in front of you.

Start with today’s body. Build the lesson. Then build the capacity for what comes next.

This article is educational and is not individual medical advice. People with osteoporosis, previous fragility fractures, significant joint conditions or other medical concerns should receive individualized guidance before beginning impact exercise. AI-assisted research was used and verified to support the information in this article, because manually researching every claim as a studio owner is not always practical.

References

1. Turner CH, Owan I, Takano Y. Mechanotransduction in bone: role of strain rate. American Journal of Physiology. 1995;269(3 Pt 1):E438-E442. https://doi.org/10.1152/ajpendo.1995.269.3.E438

2. Bassey EJ, Rothwell MC, Littlewood JJ, Pye DW. Pre- and postmenopausal women have different bone mineral density responses to the same high-impact exercise. Journal of Bone and Mineral Research. 1998;13(12):1805-1813. https://doi.org/10.1359/jbmr.1998.13.12.1805

3. Uusi-Rasi K, Kannus P, Cheng S, et al. Effect of alendronate and exercise on bone and physical performance of postmenopausal women: a randomized controlled trial. Bone. 2003;33(1):132-143. https://doi.org/10.1016/S8756-3282(03)00082-6

4. Watson SL, Weeks BK, Weis LJ, Harding AT, Horan SA, Beck BR. 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. 2018;33(2):211-220. https://doi.org/10.1002/jbmr.3284

5. Snow CM, Shaw JM, Winters KM, Witzke KA. Long-term exercise using weighted vests prevents hip bone loss in postmenopausal women. The Journals of Gerontology: Series A. 2000;55(9):M489-M491. https://doi.org/10.1093/gerona/55.9.M489

6. Aboarrage Junior AM, Teixeira CVS, Dos Santos RN, et al. A high-intensity jump-based aquatic exercise program improves bone mineral density and functional fitness in postmenopausal women. Rejuvenation Research. 2018;21(6):535-540. https://doi.org/10.1089/rej.2018.2069