| Why you should weight train |
By Dr. Michael Colgan Reproduced
with permission of Les Mills Australia
Need a reason to weight train? Here is a summary of
the latest research on the benefits of weight training.
Between the ages of 20 and 40 the average female loses 3.6 kg of muscle
and gains 10 kg of fat. Between 20 and 80 the average male loses one
quarter of his muscle mass. Running, cycling or other aerobic sports
will not prevent this loss. In a representative study of the evidence,
researchers at McMaster University, USA, compared a ten week program
of weight training plus aerobic exercise against aerobic exercise alone.
The aerobic group showed only a 2% increase in cardiovascular capacity
and an 11% increase in endurance. The weight training plus aerobics
group showed a 15% increase in cardiovascular capacity and a massive
109% increase in endurance. For strength the results favoured weight
training even more. The aerobics group showed no increase in arm or
leg strength. The weight training group showed a 43% increase in arm
strength and a 22% increase in leg strength.
Muscle is the engine in which body fat is burned for fuel, so if you
don't have much muscle you can't lose much fat. A representative study
published in the American Journal of Clinical Nutrition compared the
levels of body fat in groups of women, showing sedentary women have
21 % body fat, aerobic exercisers have 16% body fat, and resistance
exercisers have 14% body fat.
The bone benefits of weight training are well illustrated by a study
of bone density in weightlifters from 14 different countries, compared
with healthy subjects who didn't lift weights. On average the weightlifters'
bones were 46% more dense and an estimated 50% stronger.
Bone strength and muscle strength are highly correlated not only in
weightlifters but also in healthy young women. A study at Stanford University
showed clearly that about 20% of bone mineral density is dependent on
maintaining muscle.
A new study reported in February 2000 in the British Journal of Sports
Medicine shows that even in elderly women, a one-year weight training
program increased their strength by 19-29%, with a concomitant increase
in bone density
Immune strength depends on availability of the amino acid glutamine,
and your muscles have to supply the glutamine to your immune system
in order for it to work. The more muscle you have the more abundant
the glutamine supply, and, other things equal, the better your immune
system works.
New studies published between 1995 and 1999 show that weight training
has an unexpected benefit - it improves glucose tolerance in patients
with Type 2 (adult-onset) diabetes. In one of these studies, post-menopausal
women with diabetes followed a weight training program for four months.
Their glucose sensitivity to a challenge improved by an average of 29%.
At Tufts University, researchers gave patients with rheumatoid arthritis
12 weeks of high-intensity weight training. Results showed significant
reductions in joint pain and fatigue and a big gain in strength. Another
study at the University of Nebraska gave a group of patients with osteoarthritis
of the knee an 8-week strength training program. Another patient group
with the same arthritis was used as a control. Results showed that the
weight work caused a significant decline in arthritis activity.
Research shows that weight training causes fewer heart symptoms than
traditional rehabilitation exercises like fast walking, jogging or cycling.
It also yields better coronary artery flow, greater muscle strength,
greater submaximal endurance and less fatigue.
In one new study, a 12-week weight program was added to a conventional
heart rehabilitation aerobic exercise program. The group doing weights
plus aerobics showed much greater increases in strength (90% as opposed
to 9% on aerobics alone). They also lost more body fat (2.8 kg as opposed
to 1.3 kg). And they showed greater improvements in endurance.
This handout is provided by Network for Fitness
Professionals
P0 Box 57, Neutral Bay, NSW 2089.
Web site: www.globalfit.net
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