Your bones are not dead scaffolding. They are living tissue, and they pay close attention to how hard you land. A long, gentle walk tells them very little. A few sharp jumps tell them a lot. Over the past few decades, researchers have found that short bursts of impact, sometimes only a handful of hops a day, can make bones bigger and stronger, from schoolchildren to men in their seventies. Here is what jumping does to a skeleton, how little of it seems to be needed, and who should start small.
This article is for general information only and is not medical advice. If you have osteoporosis, past fractures, joint problems, or another health condition, talk with a doctor or physiotherapist before adding jumps or hops to your routine.
Bone is always listening
Every bone in your body is being rebuilt all the time. Cells called osteoclasts dissolve small patches of old bone, and cells called osteoblasts lay down new bone in their place. Buried inside the hard bone is a third kind of cell, the osteocyte. Osteocytes sit in tiny chambers linked by thin channels, and they act like a network of strain sensors. When a bone bends very slightly under load, fluid moves through those channels, and the osteocytes send out signals that tilt the balance toward building.
What the sensors seem to care about is not just how heavy a load is, but how fast it arrives. A quick, hard landing bends bone more sharply than standing still or strolling, even if your body weight is the same. That is why steady, supported exercise does less for bones than you might expect. The Royal Osteoporosis Society, a British charity, points out that swimming and cycling are great for general fitness but are not impact exercise, because the water or the bike carries your weight.
Bones also respond locally. The bone that gets the jolt is the bone that changes. Your hip does not get stronger because you did push-ups, and your wrist does not get stronger because you went jogging.
What happens when the load disappears
The clearest proof that bones need load comes from people who lose it entirely. In orbit, nothing presses down on the skeleton. NASA says astronauts on the International Space Station lose roughly 1 to 1.5 percent of their bone mineral density per month in weight-bearing areas like the hips and spine, on typical missions of four to six months. On Earth, that much loss takes older adults years.
That is why station crews exercise for long stretches almost every day, including running on a treadmill while strapped down by a harness and bungee cords. The cords pull them onto the belt so that each footstrike delivers some of the impact that gravity would provide at home.
Five jumps, then a rest
If bone likes impact, you might assume more is always better. Animal studies suggest otherwise. In a 1997 study at Chukyo University in Japan, young rats were trained to jump 5, 10, 20, 40, or 100 times a day, five days a week, for eight weeks. Just five jumps a day was enough to make their leg bones heavier and harder to break than those of rats that did not jump. The groups doing 10, 20, or 40 jumps a day did not end up much better off than the five-jump group.
A 2002 study from Indiana University added a second clue. Researchers gave rats the same total of 360 loading cycles a day on a forearm bone, either all at once or split into four bouts of 90 with three hours of rest between them. The split schedule built more bone and a stronger cross-section. Bone cells appear to tune out a signal that keeps repeating, and they need a few hours to become sensitive again.
For people, the practical takeaway is encouraging. A short set of jumps, done regularly, seems to matter more than a long, punishing session. Several small sets spread through the day may work even better.
The arm that got twice as strong
Some of the most striking human evidence comes from baseball. Pitchers spend years whipping one arm forward at high speed, while the other arm mostly comes along for the ride. That gives scientists a built-in comparison inside the same body.
In a 2014 study in the Proceedings of the National Academy of Sciences, Stuart Warden and colleagues scanned the upper arm bones of 103 professional baseball players at different stages of their careers. The humerus in the throwing arm had nearly double the strength of the one in the other arm. After players retired, much of the extra bone mineral faded. But about half of the gain in bone size and about a third of the gain in strength were still there in former players who had stopped throwing more than 50 years earlier. Those who kept throwing as they aged held on to even more.
The lesson is that bone built when you are young can last for decades, and that staying active later in life helps you keep more of it.
Jumping kids, hopping grandfathers
Childhood is when the skeleton is most responsive. In a randomized trial published in 2001, researchers in Oregon had 89 children aged about 6 to 10 either jump or stretch at school three times a week for seven months. The jumpers did 100 two-footed jumps off a box about 61 centimeters (2 feet) high each session, landing with forces of roughly eight times their body weight. By the end, bone mineral content at the hip had grown 4.5 percent more, and at the lower spine 3.1 percent more, than in the children who stretched.
Adults can respond too, with much smaller doses. In a 2006 study, young women who did just 10 maximum-effort vertical jumps a day, three days a week, for six months, gained bone density at the hip and spine, while women who did not jump stayed about the same.
Older bones are slower to change, but they are not deaf. In a clever 2013 study from Loughborough University in England, 50 healthy men aged 65 to 80 hopped on one leg only, chosen at random, so the other leg could serve as a control. They built up to 50 hops a day in different directions, every day, for a year. Among the 35 men who finished, bone density at the femoral neck, the narrow part of the hip that often breaks in falls, rose 0.7 percent in the hopping leg and fell 0.9 percent in the resting leg. Those numbers sound small, but in older adults, simply stopping the usual yearly loss is a win. A later CT analysis of the same men found larger gains, above 6 percent, in particular spots on the femoral neck.
Can people with osteoporosis jump?
For a long time, the answer from many doctors was a cautious no. High loads seemed too risky for fragile bones. An Australian trial called LIFTMOR, published in 2018, challenged that view, at least for carefully screened people.
Researchers at Griffith University randomly assigned 101 women past menopause, with an average age of 65 and low bone mass, to one of two programs for eight months. One group did gentle home exercise. The other did two 30-minute supervised sessions a week of heavy lifting, including deadlifts, squats, and overhead presses at more than 85 percent of their one-lift maximum, along with jumping chin-ups that ended in a drop landing. Bone density in the lower spine rose 2.9 percent in the lifting group and fell 1.2 percent in the home group. At the femoral neck, it rose 0.3 percent versus a 1.9 percent drop. The only reported side effect was one minor back spasm.
Those results came from close supervision, careful technique training, and screening, not from people jumping off boxes on their own. But they helped shift expert advice. The Royal Osteoporosis Society now says most people with osteoporosis can exercise safely and recommends building up to about 50 moderate impacts, such as small jumps, skips, jogs, or hops, on most days of the week. The 50 can be spread through the day. People who have had spinal fractures or many broken bones are advised to stick with low-impact work, like brisk walking, marching, and stair climbing, building to about 20 minutes on most days, unless a doctor or physiotherapist says otherwise. Women in particular have extra reasons to keep moving as they age, as we covered in our piece on how women gain more from exercise.
A simple way to build up
The society’s own home plan starts gently and steps up in stages. Here is a version of that ladder. Move up only when the current level feels easy and steady.
| Stage | What it looks like | Examples |
|---|---|---|
| Low impact | One foot always stays on the ground | Marching on the spot, heel drops (rise onto your toes, then drop onto your heels), stair climbing, brisk walking |
| Moderate impact | Both feet leave the ground briefly and land with medium force | Small jumps, jogging on the spot, skipping rope, dancing |
| More varied impact | Moderate impacts in different directions | Hops, skater steps side to side, stride jumps, tennis |
A few habits seem to help, based on the research above:
- Keep sets short. Ten to 20 impacts at a time is plenty. Two or three short sets across the day line up with the animal finding that rest between bouts helps.
- Change direction. The hopping men in England jumped forward, backward, and sideways. Bones seem to respond best to loads they are not used to.
- Land with soft knees, on a firm, non-slip floor, in supportive shoes. The goal is a crisp impact through the legs and hips, not a jarring one through the knees.
- Pair it with strength work. Impact and resistance training work best together. Our guide to resistance training for stronger bones covers the lifting side.
Who should hold off or get advice first
Impact exercise is not for everyone, at least not right away. Get advice before starting if you have had a recent fracture, a spinal fracture, or several broken bones, or if you have painful arthritis in your knees or hips. If you feel unsteady on your feet, work on balance first, since a fall can do far more damage than a missed workout. Some people, especially after childbirth or around menopause, notice leaking when they jump. That is common and treatable, and a pelvic health physiotherapist can help. And stop if a jump causes sharp pain.
The bottom line
Your skeleton is shaped by the forces it feels. Long, gentle activity is good for your heart, but bones respond best to short, quick jolts, and they seem to need surprisingly few of them. A handful of jumps or hops, done most days and built up slowly, is one of the cheapest things you can do for your bones. Start where you are, even if that means heel drops in the kitchen, and let your skeleton catch up.
A rope to start with, and a book about your bones
Amazon Basics Jump Rope — A plain, inexpensive rope with padded foam handles. It is all you need for the skipping and small jumps in the moderate-impact stage above.
Bones: Inside and Out — Hand surgeon Roy A. Meals tours the skeleton, from how bones grow and heal to how they shape the way we live. A readable companion if this piece made you curious about what is going on under your skin.