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Posts Tagged ‘resistance’

Sarcopenia: muscle loss is the new bone loss?

August 31st, 2010

For an article I’m working on, I’ve been digging through the literature on sarcopenia, the age-related loss of muscle mass that most of us face starting in our 30s. I’ve found several conflicting estimates of how much muscle you can expect to lose, with a high end of 1-2% per year starting in your fourth decade (from this paper). That’s a lot more aggressive than I’d expected. I get the sense that it’s one of those problems whose implications we’re just now beginning to grasp — so I was interested to see this article by Andrew Pollack in the New York Times, which offers a good introduction to the topic:

Bears emerge from months of hibernation with their muscles largely intact. Not so for people, who, if bedridden that long, would lose so much muscle they would have trouble standing.

(Nice lede!)

Why muscles wither with age is captivating a growing number of scientists, drug and food companies, let alone aging baby boomers who, despite having spent years sweating in the gym, are confronting the body’s natural loss of muscle tone over time.

Comparisons between age groups underline the muscle disparity: An 80-year-old might have 30 percent less muscle mass than a 20-year-old. And strength declines even more than mass…

Much of the article focuses on attempts to agree on a clinical definition of the condition — which would then make it possible for drugmakers to win approval from regulators for drugs to treat it. But the key point for me is:

Researchers involved in the effort say doctors and patients need to be more aware that muscle deterioration is a major reason the elderly lose mobility and cannot live independently.

In other words, I need to start doing my push-ups again. Soon.

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Building muscle with light weights

August 11th, 2010

Another interesting strength-training study just popped up, this one published in PLoS One. The claim in the press release is quite eye-catching: “Building muscle doesn’t require lifting heavy weights.” This is a leap of logic that isn’t quite supported by the paper itself, whose claims centre on “stimulating muscle protein synthesis ” and “inducing acute muscle anabolism” rather than actually demonstrating big muscles. Still, it’s a very surprising study, from a well-respected group (Stuart Phillips at McMaster University).

The study compared three different weights routines:

(1) lift at 90% of one-rep max until failure;

(2) lift at 30% of one-rep max until you’ve lifted as much as you did in the first routine;

(3) lift at 30% of one-rep max until failure.

Deeply entrenched dogma tells us that the best way to build big muscles is to lift heavy weights — option (1) in the workout routine. But the researchers injected tracers and took muscle biopsies four and 24 hours after each workout to find out what was happening on a cellular level. They found that the first and third routines were the same on most measures of protein synthesis, and the third routine was even better on some measures. Those new proteins being synthesized are what accumulate, over time, to produce bigger muscles. So as long as you’re lifting until can’t lift anymore, you’ll do as well or better with light weights as you would with heavy weights.

This is some serious heresy being proposed, and it’s important to note that they didn’t actually observe bigger muscles, just cellular markers. The researchers themselves note that “a training study in which these distinctly different exercise loads are utilized is clearly warranted to confirm our speculation.”

Whatever the training study eventually shows, it’s hard to imagine that this will affect how serious muscle-builders train. However, the researchers believe it could have important implications for “people with compromised skeletal muscle mass, such as the elderly, patients with cancer, or those who are recovering from trauma, surgery or even stroke,” since it minimizes the risk of orthopedic and soft-tissue injury. I’d generalize that even further — there are many, many people who are intimidated by the prospect of trying to lift heavy weights, but might be willing to lift a lighter weight 20 or 30 times until they can’t lift it anymore. Of course, that’s the crux: the method only works if you reach failure, so it’s still going to hurt. You’re just less likely to cause a scene at the gym by dropping the weight on your foot.

Ballistic power vs. strength training for athletic performance

August 11th, 2010

If you’re trying to step up your basketball (or tennis or soccer or whatever) game, which weights routine is better:

(1) three sets of three back squats at 90% of one-rep max; or

(2) seven sets of six jump squats at less than 30% of one-rep max?

The conventional wisdom is that ballistic power training carries more bang for your performance buck, since it simulates the movements you’ll be making at realistic speeds. Other than in sports like weightlifting and football, it seldom matters what your absolute maximum strength is, especially if you can’t summon it instantly.

Certainly, if you’re Roger Federer, you’ve got a custom-tailored, periodized training plan that incorporates both pure strength and ballistic work. But what if you’re an average, non-professional athlete? A study by New Zealand researchers in the current issue of Medicine & Science in Sports & Exercise pits these two workout regimens against each other in a group of 24 “relatively weak” volunteers, measuring functional outcomes like maximal power output, jump height, movement velocity and sprint performance. The result: after 10 weeks, the two groups were pretty much identical (and significantly better than untrained controls in all measures).

In both cases, the adaptations were primarily neuromuscular — signals from the brain to the muscles were transmitted and executed more effectively. (The precise neuromuscular changes were different in the two groups: the ballistic group was able to produce force more quickly, while the strength group increased the magnitude of their contractions, but the performance results were the same.) These neuromuscular adaptations are precisely the point of ballistic training — to some extent, that’s all you get from it. The surprising result in this study was that, for “weak” people who haven’t already done a lot of weightlifting, ordinary strength training produces comparable neuromuscular benefits. But if you keep at it, strength training will eventually also produce significant structural changes — i.e. bigger muscles — that provide further performance benefits.

So the moral of the story, according to the researchers, is that recreational athletes who’d like to improve their performance should choose strength training. It’ll give them all the benefits of neuromuscular training, with the possibility of additional muscle growth if they keep at it.

From my point of view, there’s another moral we can draw from it, which is that, if you haven’t been lifting any weights, pretty much anything you do is going to trigger those neuromuscular gains and improve your performance — so don’t get hung up on the details, just do it.

Jockology: does a personal trainer help?

May 3rd, 2010
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A new Jockology column is now posted on the Globe and Mail website, taking a closer look at some of the research into personal trainers (a topic I blogged about a few months ago):

The question

Will I get a better workout if I hire a personal trainer?

The answer

In a famous study at Ball State University in Indiana, researchers put two groups of 10 men through identical 12-week strength-training programs. The groups were evenly matched when they started, and they did the same combination of exercises, the same number of times, with the same amount of rest.

At the end of the experiment, one group had gained 32 per cent more upper-body strength and 47 per cent more lower-body strength than the other. No performance-enhancing pills were involved – the only difference was that the more successful group had a personal trainer watching over their workouts.[READ ON…]

One of the key punchlines: people with personal trainers choose to lift heavier weights, and thus make more progress. Left to their own devices, many people choose weights that are less than 40-50% of their one-rep max, and thus pretty much ineffective for stimulating strength gains.

Can strength training combat chronic back pain?

March 4th, 2010

This week’s Jockology column takes a look at some rather surprising research from the University of Alberta on back pain and lifting weights:

The question

My lower back is killing me. What can I do about it at the gym?

The answer

It’s the classic moving-day injury: You’re hoisting a dresser or grabbing one end of a sofa, then – bam! – you throw out your back.

So it may come as a surprise to hear that a promising solution for chronic lower-back pain, according to a series of recent studies from the University of Alberta, is lifting weights. A whole-body strengthening program dramatically outperforms aerobic exercise for those whose nagging back pain lingers for many months, the researchers say. And the more you lift, the better. [read on…]

There’s always a risk in reporting on research like this that it will get taken out of context. I should emphasize here this research applies to chronic (i.e. not immediately after you throw your back out) and non-specific (i.e. not related to a specific disc or muscle problem) back pain. And it’s not advocated strengthening the lower back itself — it’s strengthening other areas of the body, like the arms and legs, to take some load off the back.

For that matter, even that diagnosis remains controversial:

This one-size-fits-all approach has limitations, though, according to Stuart McGill, a professor of spine biomechanics at the University of Waterloo .

“There’s actually no such thing as non-specific back pain,” he says. “It just means you haven’t had an adequate assessment.”

Still, the results of the studies are interesting — and very much worth thinking about, in my opinion. They’re just not for everybody with back pain.

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Is hiring a personal trainer worth it?

February 15th, 2010

Hiring someone to tell you what exercises to do seems like a reasonable proposition — after all, there’s a big difference between a well-planned exercise program and just puttering around the gym. But what about after you’ve learned the details of the program: is it still worth paying someone to come and watch you work out?

According to a new study in the Journal of Strength and Conditioning Research, yes. (And yes, I’m aware that JSCR is the official organ of the National Strength and Conditioning Association, which may have a vested interest in promoting this idea.)

The study, by researchers at the University of Brasilia in Brazil, builds on previous studies that have found that people doing weight training build more muscle and gain more strength when they’re supervised than when they’re on their own. In this case, the study compared 124 untrained young men, and had them undertake an 11-week training program with either a coach for every five athletes or a coach for every 25 athletes. Sure enough, the more highly supervised athletes gained significantly more strength in bench press and knee extensor exercises.

As the paper explains, personal trainers “may help to control important training variables such as load, rest intervals, and exercise technique and to provide motivation and psychological reinforcement,” so it’s hard to nail down exactly what’s happening. But the data provide some interesting insights.

One initially confusing fact is that the total volume of weight lifted was pretty much the same between the two groups. On closer examination, what happens is that the less-supervised group picks a slightly lighter weight and lifts three sets in a nice, controlled manner. The heavily supervised group picks a more ambitious target, reaches failure during the third set, and has to stop a few reps earlier. Total volume is the same, but the guys reaching failure get bigger training benefits.

I certainly don’t discount the effect of knowledge and supervision (e.g. to ensure correct form, especially in inexperienced exercisers), but my interpretation is that motivation is the key differentiator between the two groups. I think most people would agree intuitively that personal trainers can help people push harder than they would otherwise. But for those who can’t or don’t want to spring the cash, it seems to me that a good training partner can help serve a similar role — especially if you’re close to the same abilities, and you don’t want to have to re-rack the weights between each set!

How fast can you build muscle and strengthen tendons?

February 9th, 2010

There’s an interesting study in the latest issue of the Journal of Strength and Conditioning Research about how quickly your muscles and tendons adapt to exercise — and un-adapt when you stop exercising. (Thanks to Steve Magness for pointing this study out.)

The set-up: 8 subjects did three months of strength training (knee extensions), four days a week, and then stopped training for three months. Once a month, researchers from three Tokyo universities measured changes in the affected muscles and tendons, using high-voltage electrical stimulation, ultrasound, MRI and other techniques.

The results: The subjects were significantly stronger after two months, mostly because of better neural activation. The muscles didn’t get bigger until after three months. The tendons also didn’t get significantly stiffer until after three months.

When the subjects stopped training, the pattern was reversed. After just one month, muscle size dropped back to pre-study levels, while strength stayed significantly higher even three months later. Tendon stiffness dropped to pre-exercise levels after two months.

So what does this tell us? First of all, you need to start pumping iron at least three months before you hit the beach. But more generally, it confirms that tendons adapt more slowly to training than muscles (and then lose training more quickly than muscles). This, the authors hypothesize, is because tendons have slower metabolism — as mediated by blood flow and oxygenation — than muscles.

From a practical point of view, this tells us that there’s a period of mismatch after starting a new training program, where the muscles have adapted but the tendons haven’t yet caught up. This creates a risk of, for instance, Achilles tendon ruptures. The solution? Be cautious. Maybe start that weights program four months before beach season, so you don’t have to push it quite as hard.

Cooling your palms enables you to bench press more weight

February 9th, 2010

Another result from the Department of Weird and Unexpected Ergogenic Aids… A forthcoming paper in Medicine & Science in Sports & Exercise, by researchers at the University of New Mexico, finds that cooling your palms between sets of bench press allows you to lift more weight.

The details: 16 subjects performed four sets of bench press at 85% of one-rep max, with three minutes rest. Between sets, they stuck their hands in a Rapid Thermal Exchanger, which heats or cools while applying a negative pressure. Their palms were either heated to 45 C (113 F), cooled to 10 C (50 F), or left at room temperature. Sure enough, they lifted more when their palms were cooled, including a remarkable 30 percent increase in the second set.

So what does this tell us? Well, for one thing, it tells us that people are going to start buying Rapid Thermal Exchangers, or at least bring ice packs into the weight room. But more interestingly — and this is becoming quite a theme on this blog — it adds new evidence in support of the “central governor” model.

If cooling our palms (which are far away from the muscles involved) allows us to lift more weight when lifting to failure, this tells us that the “failure” wasn’t due to some mechanism in the muscle fibres themselves. Instead, when the input to the central nervous system was altered by triggering cold sensors far away from the relevant muscle, the shut-down signal didn’t get sent to exhausted muscles quite as soon. It’s far from clear exactly what’s happening with this weird effect, but the researchers are quite confident that it has something to do with centrally mediated nerve signals — and thus adds support to the idea of a central governor.

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Exercise for back pain

June 7th, 2009

The biggest conference in sports science, the annual meeting of the American College of Sports Medicine, wrapped up last week in Seattle. It’ll take a few weeks to sort through the rubble and pull out the worthy new studies, but I figured I’d start with a University of Alberta study on back pain, since it’s something that will afflict about 80 percent of North Americans at some point in their lives.

Researchers took 240 people with chronic lower-back pain, and had them exercise with weights two, three or four days a week, or else not at all. The verdict:

“While it could be assumed that someone with back pain should not be exercising frequently, our findings show that working with weights four days a week provides the greatest amount of pain relief and quality of life,” said Robert Kell, lead author of the study…

Over the course of the 16-week study, the four-a-week group reduced pain by 28 percent, the three-a-week by 18 percent, and the two-a-week by 14 percent. Obviously we’ll need some more details of what, exactly, the exercise program consisted of — but it seems to jive with the general trend towards active recovery rather than immobilization.

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Does aerobic exercise make you instantly smarter?

March 16th, 2009
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It’s old news that exercise is good for the brain. Dan Peterson of 80percentmental does a nice job of summing up some of the benefits here: increasing blood flow to the brain, making new brain cells, managing glucose. We usually think of that in terms of long-term benefits — stay active to avoid losing your marbles.

That’s why a forthcoming study (now available online) in Medicine & Science in Sports & Exercise caught my attention. Read more…

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