The 38-second daily exercise that transformed my mid-life body

Every other day, I have a ritual that leaves me breathless but triumphant. It takes 38 seconds, costs nothing and needs no equipment. It might make me look slightly unhinged, but it’s benefitting my health – and could help yours, too.

What is it? I jump. Or squat jump, to be precise. Starting with my feet flat on the floor, shoulder width apart, I squat, my elbows bent and hands in front of my chest, before jumping as high as I can, pushing my arms down to help make the movement as explosive as possible.

I land back in a squat with a thud. Then I go again, and again, until I’ve jumped 32 times (four sets of eight) and am gasping for air. Not (just) because I am mad or for the cardiovascular exercise, but because I am strengthening my bones, reducing my risk of fractures and breaks in later life.

As children, most of us jumped unthinking, from trees and climbing frames, over ropes, on bouncy castles. Then we got desk jobs, lost muscle and maybe some confidence, and the concept of propelling ourselves into the air for the sake of it begun to feel more jarring than joyous.

But, jumping is one of the best things we can do to improve bone density, which starts to decline after 30, says strength training coach Sarah Best (@findurfituk).

When we land after a jump, we create a ground reaction force – the force the ground pushes back on our body – “which stimulates bones to lay down more bone tissue,” she explains. The ground reaction force of walking is around 1.5 times our bodyweight, and running around 2.5 times. Research in the British Journal of Sports Medicine found “simple jumps” produced ground reaction forces of between 3.5 and five times our bodyweight – so are “brilliant for supporting our skeletal system,” says Best.

For mid-life women like me, they are more important than ever, because bone density decline is accelerated as levels of oestrogen – which suppresses the cells that break down old bone – also fall. No great time commitment is needed, stresses Best. “A couple of minutes three times a week is enough to benefit. You definitely don’t have to spend hours jumping.”

In fact, a study of 60 women aged 25 to 50 in Sage Journals found those who jumped 10 or 20 times, twice daily, for 16 weeks had “significant” improvement in hip bone density to those who did no jumping. The women rested for 30 seconds between each jump.

Another trial in the journal Bone found three jumping sessions a week with 10 seconds rest in between each jump improved the bone density of mid-life men after a year.

“Leaving a pause between jumps is as much about reducing the risk of knee injury as anything else, in what is essentially a repetitive loading exercise,” says sports scientist Dr George Bownes, founder of sports medicine clinic Citius Health. Thankfully for me, given I don’t break between jumps, he doesn’t believe these pauses have any additional benefit to bone density, although says holding my jump at the bottom of my squat will help improve my strength.

Jumping, a form of plyometrics – fast, explosive movements that also include hopping – engages fast-twitch muscle fibres, which decline quicker than slow-twitch muscle fibres, required for endurance, as we age.

It improves our power, or how fast we generate force, and our co-ordination. “It trains your nervous system to land safely, react quickly and control your body’s position in the air and on landing,” says Best.

Famous fans include actor Jennifer Garner, 54, who has filmed herself jumping onto a box as part of her fitness regime, and celebrity orthopaedic surgeon and longevity guru Dr Vonda Wright, who advises 20 jumps a day.

It only occurred to me to start jumping regularly as an adult after a beach holiday when my two teenage children were younger. Wanting some sort of workout, I jumped on the sand as I watched them play. Just 10 jumps felt challenging on hard sand – in part, perhaps, because I was barefoot. “If you can tolerate jumping without trainers it is better for your bones as you land with more impact,” says Best, who concedes, however, “it’s a balance between improving bone health and avoiding injury – after several knee operations I tend to keep my trainers on”.

In any case, I realised I should practice more and over the years have built my way up to 32 jumps, which I now tag on to my home weights routine.

Having enough muscle to support your joints and tendons as you jump is key or you risk injuring them, caveats Best, who says strength training is essential for jumpers, and suggests those new to jumping start with a heel drop: “Go up onto the balls of your feet then drop your heels to the floor as hard as you can.” Jumping on rebounders – mini trampolines designed for exercise – is “better than nothing but not really enough,” she adds.

Should I want an extra challenge, Best recommends single leg hops, which improve balance and proprioception – our body’s ability to sense where it is without looking, adding “jumping forwards, backwards and side to side will work the medial and lateral ligaments on the inner and outer knee, which can help protect against knee injuries”.

Broad jumps – “where you jump forward with both feet as far as you can” – will develop my explosive power, she says, as will jumping onto a box, a la Garner, which targets the glutes and quadriceps.

Compared to the effort of lifting dumbbells, jumping feels relatively fun, transporting me back to my youth, when exercise was part of playtime not a prerequisite for health. Up in the air, I feel childlike and free – even if I am fit to drop by the end.