From The Desk Of Clarence Bass
“Perhaps the most interesting finding from our work is that
hypertrophy in the 80% [3 sets] and 30% [3 sets] conditions was equivalent… [but
training load] did have a clear impact on…strength gains.”
Study Confirms Light and Heavy Weights
Equally Effective for Building Muscle
A training study from the Stuart Phillips-led research team at McMaster University in Canada confirmed their earlier finding that light weights are just as effective for building muscle as heavy weights; the key to building muscle is the effort put into each set. In an important new finding, their data hewed to the long-established specificity principle in building strength; to lift heavy weights you must lift heavy weights. Finally, their results also suggested that additional volume—more sets—may build more muscle.
What they found and what it means is of interest to everyone who lifts weights.
A distinguishing feature of the new study is its 10 week time-span. Their two earlier studies tested the effect of a single bout of training. One study (Burd, PLoS, August 9, 2010) compared the effect of training to failure with 30% and 80% of 1RM, while the second study (Burd, Journal of Physiology, August 15, 2010) compared training to failure with 70% of 1RM for 1 set and 3 sets. The first study found no difference in the resulting muscle gain, while the second study found that 3 sets builds more muscle than 1 set.
The new study (2012) tests the effect of training to failure three times a week under three different training conditions: 1) One set at 80% of maximum load, 2) Three sets at 80% of maximum, and 3) Three sets at 30% of maximum.
The test exercise was the unilateral knee extension (for building the muscles on the front of the thigh). Changes in muscle size were measured by magnetic resonance imaging (MRI) and strength by increases in one-rep maximum (1RM).
All three training conditions produced significant increases in quadriceps volume. The heavy and light groups doing 3 sets gained essentially the same: 30% load produced an increase of 6.8%, and 80% produced a gain of 7.2%. The group doing a single set to failure with 80%, however, showed a gain of only 3.2%, about half as much as the groups doing 3 sets.
Strength gains were more tightly bunched. All three training conditions produced significant increases in 1RM strength, but the increase was a bit greater in the groups lifting 80% for 1 and 3 sets. The difference in strength gain was small, but undeniable.
So what does it all mean?
First and foremost, the 10-week training study confirms the findings of the earlier single-bout studies by the same group—and largely validates Dr. Ralph Carpinelli’s concept of effort-based training. (See article # 230) For muscle building, it makes no difference whether the weight used is heavy or light. The choice is yours. Professor Stuart Phillips summed it up for Science Daily (April 30, 2012): “Our study provides evidence for a simpler paradigm, where a much broader range of loads including quite light loads can induce muscle growth, provided it is lifted to the point where it is difficult to maintain good form.”
The departure came in building strength, where heavy weights provided a slight but significant advantage. The long-established specificity principle asserted its primacy. “These data confirm the specificity principle of training in regards to muscle strength and endurance,” Cameron-Phillips and colleagues wrote in summarizing their findings.
“These results suggest that practice with a heavy relative load is necessary to maximize gain in 1RM strength,” the researchers wrote. “These observations are in line with previous work which has shown that strength gains are specific to the movement that is trained and strength gains are due to a combination of muscle hypertrophy and neural [nerve impulse] adaptations,” they continued. “However, it appears that neural adaptations are largely specific to the movement and load used in training.”
Think about that; it makes sense. Lifting an 80% load requires a more dynamic nerve impulse than lifting a 30% load, especially on the first rep or two. That explains why Olympic weightlifters, who must marshal all their muscle fibers for one Herculean effort, spend the lion’s share of their training time doing single lifts.
On the other hand, an endurance athlete would probably be well advised to lift lighter weights for more repetitions. Notably, the 30% load group in the new study recorded a 30% increase in type 1 endurance fibers compared to only 18% in type 2 strength fibers. Interestingly, the group lifting 80% for 3 sets produced a balanced increase in endurance and strength fibers, 17% and 16%, respectively.
For the vast majority of people—who aren’t concerned with how much weight they can lift one time—the point to remember is that both light and heavy weights produce significant gains in muscle size and strength. “These data show that hypertrophy is generally beneficial to all strength and power tests…,” the Cameron-Phillips team reported. Muscle drives functionality; it helps you stand up, walk, run, jump, and do the things necessary to live a rewarding and independent life.
Finally, we have the conundrum of sets and muscle size. As noted, the group doing one set showed only half the increase in muscle size seen by the groups doing three sets. Their earlier study produced a similar result—and called for a training study “to delineate the superiority of 1 set or 3 sets for inducing hypertrophy.”
We now have the training study, but the jury is still out. Unfortunately, the difference between the 1 set and 3 set groups was not significant. “Interestingly, there was no statistical difference in the degree of quadriceps hypertrophy between the 80%-1 and 80%-3 conditions, despite a mean gain...of ~7% in the 80%-3 condition and only ~3% in the 80%-1 condition,” the researchers wrote. “It appears that longer-term training studies may be required to manifest these differences more clearly.”
The statistical problem apparently arises out of “the inherent variability in individual response to resistance training,” the researchers related. “In fact, when subjects are stratified as high and low responders 20-25% of subjects exhibit very limited hypertrophic response whereas the top 20-25% show robust muscle hypertrophy that is four to five times greater than that seen in low responders.”
Cameron-Phillips and colleagues cautiously concluded: “The results from our study…suggest that additional training volume in the form of more sets may results in greater muscle hypertrophy.” (Emphasis mine)
Unfortunately, that may be as good as it’s going to get on the sets issue. It may come down to a matter of personal preference.
Cameron-Phillips et al are however clear on the main finding: “A lower load lifted to failure resulted in similar hypertrophy as a heavy load lifted to failure.”
* * *
As I see it, the problem with doing multiple sets is focus. It is very difficult to maintain quality—or intensity—and do many sets. While that’s not likely to be a problem in a research setting with a technician overseeing every rep, it is a problem in actual practice. When you plan to do multiple work sets, consciously or unconsciously, you pace yourself; you hold back on the early sets, saving energy for the sets to follow. Like a long-distance runner, you husband your strength. The likely end result is that some muscle fibers go unused.
On the other hand, do only one work set and you can focus totally on that set without thinking about the sets to come. You are free to make an all-out effort; you don’t have to hold anything in reserve. As in a 100-yard dash, you give it all you’ve got from start to finish. The result is a more intense set, which forces more muscle fibers into action.
Nevertheless, I know that many readers will want to do or try three (or more) sets—as I do from time to time. The difference is that I change the movement or the load on each set; I rarely do the same thing twice. That keeps the challenge fresh and the effort intense. I’ll give two examples. (I almost always do one or more warm-up sets before the work set.)
On the leg press, I do the heaviest set first, and then one or two drop-back sets. (I rest between sets.) The top weight wakes up muscle fibers that go unused in the warm-up sets, producing an enhanced response on the drop-back set or sets. For example, I might do 12 reps with 500, 20 with 450, and 25 with 400. The response is staggering; I can barely walk afterward.
Secondly, I do one all-out set with three different exercises for the same body part. For example, for the upper back I do the Nautilus pullover, the lat pulldown, and the dumbbell bent row. This is my normal workout pattern for most body parts; it works especially well for the upper back and chest.
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