Here’s a pretty graphic illustration, from a recent paper by Dr. Vonda Wright and her colleagues (hat tip to Laura McIntyre for the forward), of the importance of lifelong physical activity:
It’s from a new study freely available at The Physician and Sportsmedicine that took detailed measurements of 40 masters athletes between the ages of 40 and 81, and found a surprising lack of age-related muscle loss:
This study contradicts the common observation that muscle mass and strength decline as a function of aging alone. Instead, these declines may signal the effect of chronic disuse rather than muscle aging.
An interesting figure from a new Australian study in the European Journal of Applied Physiology:
The subjects in the study did eight weeks of heavy weight training — using only one leg (their dominant one). As you can see, they dramatically increased strength in both legs. This effect is well known, but I still think it’s pretty cool! The goal of this particular study was to try to figure exactly how this happens, using magnetic pulses to the brain to help assess the role of the nervous system. They did indeed find a significant reduction in “corticospinal inhibition” in both legs, suggesting that the training improves the transmission of the signal from the brain to the muscle, and this improvement applies to both sides of the body.
The point? Well, as the researchers note, it’s something to bear in mind if you have an injury in one leg or one arm. You might be able to keep the injured limb strong without even exercising it. Of course, you have to balance that against the risk of creating physical imbalances. I guess the ideal would be to train enough to increase strength without actually putting on muscle. As the researchers conclude, clinical trials of this approach are needed.
Another study on whole-body cryotherapy (or “cryosaunas,” or whatever you want to call them), from the same group at the French National Institute of Sport that published a similar study last summer. The full text is freely available online, along with a press release.
The study took nine well-trained runners, and had them perform three “hilly” treadmill runs, each time with a different recovery routine:
- Cryotherapy (3 minutes at -110 C), taken immediately, 24 hours, and 48 hours after the run;
- Far infrared therapy, also taken at the same three intervals;
- Nothing (“passive”).
The basic results, according to the paper: cryotherapy “accelerates recovery from exercise-induced muscle damage to a greater extent than far infrared or passive modalities.” That’s based on better results for perceived pain and maximal voluntary muscle contraction. Here’s the muscle data:
So yeah, one hour after the run, the cryotherapy allowed the runners to clench a little harder, and those results appeared to more or less persist for a couple of days. But these aren’t placebo-proof, since the runners weren’t blinded to the modality. What about a more placebo-proof measure of recovery? Well, not so good. Creatine kinase levels in the blood weren’t improved. In fact, if you look at the data and squint a bit, you might conclude that far infrared is the best choice! Uh oh.
Seriously, this study is a good start, but cryotherapy still has a ways to go. I would have liked to see it compared to conventional ice-bath therapy (which itself seems to produce more ambiguous results than you’d expect when it’s tested). Because surely we’re hoping that this therapy is actually an improvement on the current standard-of-care (which is not far infrared), rather than just a way to save seven minutes after a game or workout.
A new study in the American Journal of Physiology revisits a very familiar topic — cardio versus weights — to determine which is better for reducing dangerous visceral and liver fat. A total of 155 subjects completed one of three eight-month training programs:
- Aerobic (AT): ~12 miles per week at 75% VO2max;
- Resistance(RT): 3 days a week, 8 exercises, 3 sets of 8-12;
- Aerobic/resistance (AT/RT): both the above programs combined.
At the end of the eight months, they used some pretty sophisticated tools to measure the outcomes, including CT scans to measure levels of visceral and liver fat. Here are some of the key outcomes:
And here’s how the researchers sum up the findings:
First, a resistance training program–even a very substantial one–did not significantly reduce body mass, visceral fat, liver fat or ALT liver enzyme levels. RT also did not reduce total abdominal fat, nor did it improve fasting insulin resistance. Second, in contrast to RT, a typical vigorous AT program resulted in significant reductions in visceral fat, liver fat and abdominal subcutaneous fat, and also led to improvements in circulating ALT and HOMA (fasting insulin resistance).
The results aren’t too surprising: as the researchers note, this particular aerobic training program likely burned about 67% more calories than the resistance program. It does seem a bit strange to me that adding resistance training to the aerobic training seems to make things worse rather than better — but the overall analysis in the paper says that AT and AT/RT are statistically indistinguishable. In other words, the weights add nothing. Don’t get me wrong: weights are useful for a lot of things, and this study was only testing a few specific outcomes. But on those outcomes — and they’re very important ones, particularly if you’re overweight — cardio trumps weights.
We’ve all heard about the post-exercise “window” for refuelling to maximize recovery and adaption: you need to take in carbs and protein with 0.5-2 hours. But does the timing really matter for building muscle? A new study from Stuart Phillips’ group at McMaster University compared two tactics for post-workout protein intake. Once group took 25 grams of whey protein immediately after a set of leg-extension exercises; the other group received the same 25 grams of whey protein in 10 2.5-gram doses every 20 minutes for 200 minutes. They measured “muscle protein synthesis” — basically a very accurate way of assessing how well you’re stimulating muscle growth after a single bout rather than having to run the experiment for several months to actually see muscle growth — and found that it was much higher in the group that took their protein all at once. After six hours, protein synthesis was elevated by 193% in the single-shot group and just 121% in the prolonged group.
The question this study was seeking to answer actually relates to the difference between whey protein (which is absorbed quickly) and casein (which is absorbed more slowly: the 2.5 grams of whey every 20 minutes was chosen to mimic the absorption pattern of casein). The problem is that if you compare two different proteins in a study, then you’re changing a bunch of different factors at once — the absorption timing, but also factors like the amount of leucine, a branched-chain amino acid thought to be key for muscle growth. Since both groups received 25 grams of whey (and thus identical amounts of leucine), this shows that absorption rate is key.
Practical takeaway: this was a muscle protein synthesis study, not a training study, so you have take the results cautiously. But it does suggest that if you’re trying to build muscle, taking in a big dose (i.e. 25 grams) of protein as soon as possible is preferable to snacking over the course of a few hours. It also confirms previous findings suggesting that whey (found in dairy products) has some advantages over other protein sources.
Also in today’s Globe, I have a very short piece about foot strength for runners:
During a one-hour run, your feet push off the pavement about 10,000 times – enough of a workout to build some pretty impressive foot muscles, you’d figure.
“Considering the countless miles that runners put in, most think that they have very strong feet,” says Matt Ferguson, the president of Vancouver-based Progressive Health Innovations. “And they do – but only for one motion.”
Running does wonders for the muscles involved in plantar flexion – pointing your toes toward the floor – but leaves a host of other small muscles throughout the foot and ankle weak. The result is an increased risk of common running injuries like plantar fasciitis, shin splints, Achilles tendon problems and even ankle sprains… [READ THE REST OF THE ARTICLE]
The article takes a brief look at a few difference ways of strengthening your feet, ranging from barefoot running to old-school soup-can-in-a-sock exercises to fancy new gadgets like the AFX Ankle Foot Maximizer.
The links between strength training and efficiency in sports like cycling and running have been studied for over a decade, but a study in the European Journal of Applied Physiology offers a new twist: the role of strength training becomes increasingly important as you get older.
Researchers in France studied nine masters cyclists (average age 51.5) and eight younger cyclists (average age 25.6), and measured their “delta efficiency” before and after a three-week strength training program focused on knee extensions. Each workout consisted of 10 sets of 10 bilateral knee extensions. While the younger cyclists improved their cycling efficiency by 4.1%, the older group improved by 13.8%.
Traditionally, researchers have figured that the big decline in endurance performance with age comes from lower maximal oxygen consumption, which seems to reduce performance by about 10% per decade. The new study suggests that the muscle loss that accompanies aging could also play a key role in endurance, perhaps because inefficient fast-twitch muscle fibres have to be recruited earlier in an exercise bout. That would explain why the older athletes saw a bigger jump in efficiency when they improved their strength, even after only three weeks.
You’d expect the same thing to apply in running. Bottom line: another reason that I need to get more consistent with strength training!
I did a radio interview today with Angela Kokott on QR77 in Calgary, and one of the questions we discussed was the perennial claim that lifting weights is better than aerobic exercise for burning calories. It’s a claim that isn’t totally crazy — even the most recent American College of Sports Medicine position stand on weight loss reverses earlier stands by acknowledging the possibility that resistance training could contribute to weight loss by elevating resting metabolic rate, increasing fat oxidation, and making people more active generally. Here’s the funky flowchart they use to illustrate this process:
Still, the “evidence statement” endorsed by the position stand is: “Resistance training will not promote clinically significant weight loss.” In other words, it’s a nice theory, but the studies of actual people losing weight don’t back it up.
The reason I bring this up is that James Fell has a good article in the Los Angeles Times that tackles this topic — in particular, taking on the oft-repeated whopper that every pound of muscle burns an extra 50 calories a day. He turns to Claude Bouchard of Pennington Biomedical Research Center, who offers the following breakdown of resting metabolic rate (RMR):
Brain function makes up close to 20% of RMR. Next is the heart, which is beating all the time and accounts for another 15-20%. The liver, which also functions at rest, contributes another 15-20%. Then you have the kidneys and lungs and other tissues, so what remains is muscle, contributing only 20-25% of total resting metabolism.
The punchline, according to Bouchard: a pound of muscle burns about six calories a day while a pound of fat burns two calories a day. Don’t get me wrong: strength training is great for many reasons, and I certainly encourage everyone (including, reluctantly, myself) to do some. But it’s not a miracle weight-loss technique.
The traditional view is that it takes at least 6-8 weeks of hard resistance training before your muscles start getting bigger. You’ll see strengths gains long before that, the theory goes, but they come from neural factors (basically the “contract” signal from your brain gets the message to your muscle fibres more effectively). In the last few years, though, that orthodoxy has been challenged by a few studies that claimed to see muscle increases after just a few weeks of training. A new study from the University of Oklahoma, published in the European Journal of Applied Physiology, should help settle the debate. They set out to do a study with three key characteristics:
- Hard training: the subjects trained three times a week for eight weeks. The program was leg press, leg extension and bench press. Each exercise was three sets to failure with two minutes rest, with the weight chosen so that failure occurred after 8 to 12 reps in each set.
- Frequent testing: instead of just doing before-and-after measurements, the testers measured strength and muscle cross-sectional area every week for eight weeks.
- Sensitive measurement: a tape measure won’t cut it. They used a CT scanner to measure the muscle cross-sectional area at the midpoint of the thigh.
Here’s what they found:
The top line is muscle size, bottom is strength. The first two data points are the pre-training baseline measurements. It’s possible that the initial jump in muscle size after the first week (i.e. after just two training sessions) is predominantly due to swelling associated with muscle soreness. But the soreness had totally dissipated by week 3, so by then we’re unquestionably dealing with actual hypertrophy. By the end of the eight weeks, the total increase in muscle size (CSA) was 9.6%. Two comments. First, I was curious as to why they included bench press when all the measurements are on the legs. In discussing why an earlier study failed to see gains quite this early, the researchers note that
subjects only performed one exercise (leg extensions), so the training stimulus was not as great as that in the present study.
Does this mean that upper-body training can contribute to lower-body hypertrophy, perhaps by tweaking anabolic hormone levels and ramping up whole-body protein synthesis? I’m not sure — if anyone can clarify, please do so in the comments section. Second, this training program is hard. Three times a week, three sets of three exercises may not sound that tough — but every set is to failure (much like the controversial low-weight approach advocated by Stu Phillips, actually). If you really want to put on muscle quickly, you have to work hard.
This is a topic that should stir up some controversy: a study suggesting that you don’t need to lift heavy weights to put on muscle. I blogged about this when the study first came out a few months back; I’ve since had the chance to chat with Stuart Phillips, so I wrote a Globe column with more details:
For once, scientific studies, decades of practical experience in the gym, and logic all point to the same conclusion: you need to lift reasonably heavy weights to gain strength and muscle. The American College of Sports Medicine recommends 60 to 70 per cent of your “repetition maximum” or RM (the most you can lift for a given exercise) for novices, and 80 to 100 per cent for experts.
So recently published results from McMaster University, which suggest that you can build muscle just as well – or perhaps even better – with weights as light as 30 per cent RM, have been greeted with surprise, to put it mildly.
“There are plenty of people who just don’t believe it,” admits kinesiology professor Stuart Phillips, the senior author of the paper, which appeared in the journal PLoS ONE.
The results would be welcome news for older people and weight-room neophytes, but there is a catch. The key to stimulating muscle growth, Dr. Phillips believes, isn’t linked to any particular weight or number of repetitions – it’s reaching the point of failure, where you can’t lift anymore.
Phillips has since completed a training study that actually attempts to put these finding into practice. It’ll be exciting to see what the results of that study reveal when they’re analyzed and released.