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You Don't Have to Lift Very Heavy Weights

Exciting research from McMaster University in Hamilton, Ontario shows that you do not have to lift very heavy weights to grow large muscles (PLoS ONE. August 10, 2010).

The heaviest weight that you can lift once is called your "One Repetition Maximum" (1RM). This study questions what many non-competitive lifters do. They find their 1RM and do three sets of five repetitions at 90 percent of their 1RM.

In the Ontario study, fifteen men were assigned four sets of leg presses with one leg. They were asked to continue to extend and contract their leg muscles until they were exhausted against 30 percent of their 1RM, and against 90 percent of their 1RM. At 90 percent of their 1RM, they were usually exhausted at five to ten lifts. At 30 percent of their 1RM, they could do about 24 lifts before they were exhausted. So the lighter the weight, the more repetitions they could do. The authors used sophisticated tests for muscle growth (mixed, myofibrillar, and sarcoplasmic protein synthesis) to show that those who lifted more times at a lighter weight have greater immediate muscle growth.

This is just another case of scientists explaining and supporting training methods after athletes have used them to be successful in competition. Richard A. Winett, a professor at Virginia Tech who has published extensively on strength training, says "the stimulus from resistance training for muscle growth comes from the effort at the end of a set, where the last repetition in good form can be performed. There's no reason to use heavy resistance; moderate resistance, good form with controlled repetitions, and a longer time under tension is effective."

Dr Winett explains that for muscle growth:
• You do not have to use very heavy weights
• You should make an effort to exhaust your muscles (lift towards failure).
• Optimal growth comes from three sets to failure for each muscle and two or three exercises per muscle group.
• You should feel mild soreness on the next day. If you are very sore, you may have used too much resistance, too much volume, too large a range of motion on an exercise, too much emphasis on the eccentric part of the repetition, or you did not get enough sleep for recovery.

Do not lift weights that are so heavy that you lose form and do only partial contractions of your muscles. Try to find a workout that is not painful when you do it, but that makes your muscles feel mildly sore on the next day. As with all exercise, check with your doctor before starting a weight lifting program.


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Exercise for arthritis


Dear Dr. Mirkin: What causes osteoarthritis?

More than 27 million North Americans suffer from osteoarthritis, a painful destruction of the cartilage in joints that has no known cause and no effective treatment. Recent data from studies of moose suggest that osteoarthritis in humans may be caused by nutritional deficiencies early in life, rather than by aging, overuse or obesity as is currently thought (Ecology Letters, August 2010).

Researchers have studied moose in Isle Royale, Michigan for more than 50 years and have found from analysis of skeletons that the moose have the same type of osteoarthritis as humans. Moose who are most likely to suffer arthritis are smaller than other moose, as demonstrated by short metatarsal foot bones, which indicates that they suffered from a nutritional deficiency before they were born or in the first few years of life.

Since moose with arthritis are smaller, they had to have become susceptible to the arthritis early in life when they were still growing. Arthritis caused by wear and tear would occur later in life after the animals are fully grown. Furthermore, arthritic moose had plenty to eat in later life, which makes later life nutritional deficiency a less likely cause.

A similar pattern for poor nutrition early in life could also cause osteoarthritis in humans. People who weigh less than five pounds at birth are at increased risk for osteoarthritis (Journal of Rheumatology, April 2005). The graves of 16th-century American Indians in Florida and Georgia showed that they developed osteoarthritis after Spanish settlers arrived and taught them to farm. This shifted their diet from fish and wild plants to corn, and their children became shorter and died earlier.

The results of research on osteoarthritis are now approaching that on osteoporosis. When children are deprived of basic nutrients, they develop bones that are less dense than those of other non-deprived children. Humans have the biggest and strongest bones at ages 20 to 30. After that, they lose bone progressively for the rest of their lives. If a child has 10 percent less bone than other children, he usually has no problems in childhood. However, even if he loses bone progressively at the same rate as a non-deprived child, he will still reach a critical point in later life when he will break his bones with minimal trauma long before the children who were not deprived in early life.

What can you do now if you have osteoarthritis? Keep moving because inactivity worsens joint destruction. However you have to restrict pressure on your weakened joints and do low- impact exercises such as walking, pedaling, swimming, and squeezing a soft sponge ball. No medications delay joint destruction. Medications such as ibuprofen can reduce pain. Diets have not been shown to cure osteoarthritis, but the same rules of dieting for healthful living also apply to treating osteoarthritis: Eat lots of fruits, vegetables, whole grains, beans, seeds and nuts. You can eat eggs, fish, and poultry. Restrict mammal meat, lunch meats, and all fried and burnt foods. Maintain a healthful weight.


Dear Dr. Mirkin: Should I avoid red meat completely?

Extensive epidemiological data show that people who eat mammal meat are at increased risk for heart disease, strokes and at last 17 different cancers. However, according to a new study, it may be enough just to cut back on the amount of meat you eat. In this study, doctors followed 85,000 middle-aged female nurses for an average of 26 years, during which time 2,210 of the women had heart attacks and 952 died from heart disease (Circulation, published online August 16, 2010). Women who eat two servings of red meat per day had a 30 percent increased risk of heart disease compared to women who average three to four servings per week. Cutting back from one serving daily to one serving every other day reduces risk for heart attacks.

Many recent studies have made it unlikely that meat causes heart attacks because of its saturated fat content ( or cholesterol ( I've reported recently on the two leading theories linking meat to various diseases:
1) The sugar-protein called Neu5Gc that may cause inflammation; and
2) Methionine, an amino which increases cell growth.
Cutting back on red meat will reduce your consumption of both Neu5GC and methionine.


Recipe of the Week:

Trail Mix Bars

You'll find lots of recipes and helpful tips in The Good Food Book - it's FREE

June 21st, 2013
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About the Author: Gabe Mirkin, MD

Sports medicine doctor, fitness guru and long-time radio host Gabe Mirkin, M.D., brings you news and tips for your healthful lifestyle. A practicing physician for more than 50 years and a radio talk show host for 25 years, Dr. Mirkin is a graduate of Harvard University and Baylor University College of Medicine. He is board-certified in four specialties: Sports Medicine, Allergy and Immunology, Pediatrics and Pediatric Immunology. The Dr. Mirkin Show, his call-in show on fitness and health, was syndicated in more than 120 cities. Read More
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