Women who did a high-intensity aquatic workout for six months increased their strength and suffered fewer falls, in a study that suggests bone- and muscle-building resistance can be achieved with the right kinds of exercises.

“What we did was to test the model for muscle training in the gyms and put it inside the pools,” said lead author Linda Moreira, a researcher at the Universidade Federal de São Paulo.

The study should encourage postmenopausal women at risk for osteoporotic bone-thinning that pool-based exercise can increase muscle and bone strength.

Aquatic aerobics became popular in the 1990s as a way for older people to exercise without straining their joints or being injured in falls.

However, aquatic exercise fell out of favour, experts said, because of concerns that the bone and muscle-building benefits of resisting gravity in standard exercises were diminished when someone is buoyant in water.

To test a water workout Moreira’s group designed to increase resistance and build strength, they recruited just over 100 inactive women in their 50s and 60s.

All the women took 1,000 international units of vitamin D3 and 500 milligrams of calcium daily – both vitamins known to help build bone and muscle – during the six-month study.

Half the women were also assigned to aquatic exercise to combat osteoporosis by preventing falls, named HydrOS.

Instead of the more typical, high-repetition, low-impact aqua-aerobics, the HydrOS interval training included bursts of intense activity between 10 to 30 seconds at up to 90 per cent of maximum heart rate.