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Heavy Weights vs. Light Weights

by Fred Hahn on August 16, 2010

A new study has emerged that is being plastered all over the internet suggesting that more reps are better than less reps for building muscle. Some of the titles the writers use are different stating that lighter weights are superior for building muscle or pump less iron. Here’s another example.

These titles are a bit misleading. It is not a matter of light weights or heavy weights or pumping less or more iron. What this study is showing is that lifting weights to the point of muscular failure with a lighter weight gets the fast twitch fibers to participate equally as well as lifting a very heavy weight to failure does. So the point is when you lift, make sure to reach a point of complete muscle fatigue. However, “failure” is a negative word so we call it “muscular success” at Serious Strength.

Participants were able to lift the heavy weights in the 80-to-90 percent range from five to 10 times before fatigue set in. At 30 percent, subjects could lift that weight at least 24 times before they felt fatigue, according to lead study researcher Nicholas Burd, a doctoral student at McMaster University.

Another point here is the time spent performing a set. Most people lift and lower weights rather rapidly. Typically trainees lift and lower a weight in 1-2 seconds each way. If we use a 2/2 count (a 4 second rep), the group that used the heavy weights spent ~20-40 seconds to fatigue. The lighter weight group reached failure in ~96 seconds. Both are within the anaerobic range and will produce results.

So its your choice – use a heavy weight and get the sets over sooner and go home earlier, or use lighter weights and stick around in the gym a little longer. I do think that staying on the lighter side is better for beginners, kids, folks with orthopedic concerns and people with high blood pressure issues. I have advanced clients that simply prefer one over the other. But whichever you choose – heavy or lighter – push yourself to reach the deepest level of muscle fatigue you can to get to those fast twitch fibers. And do so safely of course.

More than one road leads to Rome. But be sure that you are at least on a road that leads there. Your sets should last no longer than 120 seconds and should be taken to complete success.

Enjoy the results!

I've been involved in exercise ever since I became a member of The Charles Atlas Club when I was 10 years old. In 1998, I founded and established Serious Strength on the Upper West Side of NYC. My clients include kids, seniors (and everyone in between), top CEOs, celebrities, bestselling authors, journalists and TV personalities.
my book. my Gym.

in Health/Fitness, Sports, personal training, strength training · 3 comments

{ 3 comments… read them below or add one }

Brandon Schultz, D.C. August 16, 2010 at 11:49 AM

Hi Fred,

Great post. I think tons of people get confused about “heavy”, “light” and what is meant by high “intensity” workouts. Close to 100% of a 1Rep Max versus high volitional effort.

HIT workouts are high in volitional effort, get a lot done in a short amount of time and, according to the studies, are effective at stimulating muscle growth. I think some assume that means heavy weights not high volitional effort.

Keep up the good fight of education Fred!

In health,
Brandon

Fred Hahn August 17, 2010 at 11:25 AM

Thanks Doc – indeed I shall!

Zach September 9, 2010 at 7:58 PM

a couple of smart guys have reviewed the study you are talking about:

http://evidencebasedfitness.blogspot.com/2010/08/if-youre-going-to-claim-to-improve.html

http://www.leangains.com/2010/08/high-reps-vs-low-reps-for-muscle-gain.html

in a nutshell, the study sucked. it claimed that light weights were just as good for building muscle, but didnt even measure hypertrophy. in fact, all it measured was protein synthesis, when hypertrophy is the result of the difference between protein synthesis AND protein degradation, but the study didn’t measure degradation. it also chose a obscure rep range, as 30% of a 1RM is ridiculously low and would often take hundreds of reps to reach exhaustion for some exercises. plus, it only looked at the short-term, and didn’t take into account any long-term adaptations that might occur

overall, this study is 100% meaningless.

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