Women who did a high-intensity aquatic workout for six
months increased their strength and suffered fewer falls, in a new study that
suggests bone- and muscle-building resistance can be achieved with the right
kinds of water 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 So Paulo. The study should
encourage postmenopausal women at risk for osteoporotic bone-thinning that
pool-based exercise can increase muscle and bone strength, according to
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.
Testing of water workouts
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 an aquatic exercise
program, which Moreira's group created to combat osteoporosis by preventing
falls, and 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% of maximum heart rate.
The water created the resistance that weights would provide on land, Moreira
Seven months later, the number of falls among aquatic
exercisers had dropped 86%, and the number of women who suffered falls dropped
44%. In the sedentary group, the number of falls remained unchanged, according
to results published in the journal Menopause.
Strength in body
The researchers also found that flexibility plus hand, back,
hip and knee strength increased in the aquatic exercisers. The women in the
sedentary group showed mild increases in balance and strength as well, but the
researchers attributed those improvements to the calcium and vitamin D
As people age, they lose muscles used for quick movements
that stimulate bone health. But, according to Moreira, typical aquatic aerobics
work muscles used for slower day-to-day movement."Physical instructors
were training the wrong muscle type," she said.
About a quarter of the study participants had osteoporosis,
half were at the beginning stage of the bone disease and the remaining quarter
had normal bones."There's this bias in the osteoporosis community against
doing any water-based exercise," said Andrea LaCroix, a researcher at Fred
Hutchinson Cancer Research Center, who studies health in older women.
LaCroix was not involved in the current study."This
study goes in the face of that," LaCroix told Reuters Health. "If
they show changes in bone density, that would be quite amazing and novel and
will be a paradigm changer in terms of osteoporosis prevention."
Exercise improved the
health of older adults
Moreira said that another
soon-to-be-published paper will show that over the six months of the study, the
aquatic exercise group maintained bone mineral density in their femur leg bones
while the sedentary women lost 1.2 % of bone density. Very little is known
about how water exercise can improve health in older adults, said Wendy Kohrt,
professor of medicine at the University of Colorado School of Medicine.
Kohrt was not involved in the current study."Without
knowing what the benefits are, it's difficult to recommend water exercise; (the
study) fills a gap in knowledge that is a pretty big gap," Kohrt
added."Improvements tended to be small (with the aquatic approach). It's a
little difficult to judge just how effective this type of exercise program
is," Kohrt told Reuters Health.
Kohrt noted that one serious limitation of the study was
that researchers didn't use equipment that could maximize muscle
resistance."There are ways to use devices in water to make it a more
effective strength training approach," Korht said, such as moving a milk
jug or webbed object through the water."The next step is to find out
whether water exercise can be as effective as more traditional land-based types
of exercises," Kohrt said.