Just six minutes of exercise per week - such as jumping - could help prevent bone thinning in women, a study suggests.
Simple exercises performed for two minutes, three times a week, could cut the risk of osteoporosis caused by the menopause, it found.
Researchers at Manchester Metropolitan University and the University of Hull examined the impact of counter-movement jumps, box-drops and heel-drops.
A counter-movement jump is performed from a standing position and involves swinging the arms to jump vertically off the ground.
To do box-drops, a person stands on a step or box set at knee-height and jumps down to land on two feet whilst bending the knees.
Heel-drops involve standing as high as possible on the toes before instantly relaxing the leg muscles and dropping on to both heels to create an impact with knees slightly flexed.
All the women in the latest study wore an accelerometer on their lower back to estimate the intensity and duration of movement.
Electrodes were also placed around the body, including at the muscle at the front of the thigh, a muscle in the hamstrings and a muscle in the back of the lower leg.
The 14 women did one jump every four seconds and then swapped to have a longer rest time, performing one jump every 15 seconds.
The results, published in the Journal of Electromyography and Kinesiology, showed both jumping regimes were beneficial for bone health.
The researchers recommended that women complete 30 jumps, three times a week.
Dr Gallin Montgomery, lecturer in sport and exercise biomechanics at Manchester Metropolitan University, said counter-movement jumps were most beneficial for women “as these had the highest muscle activation along with the highest impacts, which are really important for bone health”.
But box-drops and heel-drops also helped.
He added: “These movements are really easy and can be completed in the comfort of your own home. It would only take women seven minutes using the longer rest time and two minutes with the shorter rest time to complete.
“Often, just walking is not enough for bone health and we hope that this encourages more women to perform high-impact exercise and go some way in combating the issue.”
Osteoporosis is thought to affect around three million people in the UK, most of whom are women.