Written by justis berg
10 May 2010
Muscle Growth Update

By Robbie Durand, M.A.

Senior Web Editor

Can You Train Lighter and Still Grow?

After watching Branch Warren's new training DVD "Train Insane," bodybuilders may be thinking it's time to 'nut up' and start going balls-to-the-wall! I visited Branch a few weeks ago, and to my surprise he was taking some much-needed time to rest his body after the Olympia. He was still training, but not using the same kind of weights he was throwing around in "Train Insane."

Just a note on how strong Branch is— he was on 'active recuperation' and still military pressing 315 for 12 reps. Branch told me he was going to start ramping his training up real soon, but as I learned, even the most hardcore bodybuilder on the planet does not train balls-to-the-wall, year-round.

Eight-time Mr. Olympia Ronnie Coleman's famous quote was, "Everyone wants to be a bodybuilder, but no one wants to lift any heavy-ass weight!" As a lifter myself, I love to train heavy but sometimes the mental will to train heavy and hard is surpassed by the nervous system's ability to recuperate. I recently spoke to Dorian Yates about this and he told me, "Robbie, if I could do it all over again, I would have taken more time off and not gone so heavy close to the show. To me, training was an addiction, like sex— I just loved doing it."

Dorian told me it was not uncommon for him to be back in the gym a week after the Olympia, training again, while some bodybuilders took a month or more off. No one was more hardcore than Dorian. Those observations, coming from him, made me think— Can a person train lighter and actually grow and make progress, or is he going to turn into a fitness model?

I was going through my weekly research journals and an article jumped out at me that answered my question. The article was published in the Journal of Strength and Conditioning Research and titled, "Effects of Different Intensities of Resistance Exercise on Regulators of Myogenesis." Myogenesis refers to muscle growth. Based on the past literature, after heavy resistance exercise, genes for muscle growth are turned on. Basically, satellite cells— which just hang around muscle— are waiting to be activated to fuse with existing muscle fibers to turn on muscle growth. All they need is a stimulus. That stimulus is resistance exercise, but the question is: How heavy does one need to go to activate this process?

In the past, Myo-D and myogenin— genes involved in kick-starting the muscle growth process— have been shown to be significantly elevated in the hours following a high-intensity resistance exercise bout.1,2 So the question is, what is the minimum intensity that you can lift weights at and still turn on genes for muscle growth while your nervous system is recuperating?

Researchers from Texas did something unique— they had men train on the leg press and leg extension at two different intensities, and took muscle biopsies and examined genes for muscle hypertrophy. Participants performed two separate bouts of resistance exercise separated by two weeks during the course of the study. Each participant completed a 65 percent and 85 percent bout of single-leg resistance exercise. Each set was performed over the course of 15-20 seconds, and followed by 90-second rest periods, while 150 seconds of rest was also allowed between the two exercises. So one group was training fairly light (approximately 65 percent of 1 RM) while the second time, they returned to the lab and trained fairly heavy (around 85 percent of 1 RM). If you squatted 405 for your best lift, this equates to squatting 265 pounds during one session, and squatting 345 pounds during the other session.

You Can Trains Lighter and Still Grow!

When the researchers measured gene expression for potent stimulators of muscle growth such as IGF-1 and mechano growth factor (MGF), there was no difference between the two groups. The group that trained at 65 percent intensity had the exact same changes in genes for muscle hypertrophy as the group that trained at 85 percent intensity.

Additionally, decreases in myostatin were similar between the groups. There were virtually identical changes in gene expression for muscle growth, despite one group training much lighter. This data demonstrates that resistance exercise performed in the intensity range of 60-85 percent regulates genes for muscle growth.

It's interesting that a previous study measuring muscle protein synthesis rates found no difference in muscle protein synthesis rates when exercises were performed at intensities between 65 percent and 85 percent of a 1 RM.3

So there you have it— you can have some 'downtime' at the gym and not train as heavy. Based on the research, you will still have similar gains in muscle mass. The minimum threshold for exercise appears to be 65 percent of a 1 RM. You can ramp up your training intensity when you feel your body can handle the intense demand, but take the words of Dorian and Branch and don't be afraid to back off from the poundages— you will still make gains.

References:

1. Willoughby DS and Nelson MJ. Myosin heavy-chain mRNA expression after a single session of heavy-resistance exercise. Med Sci Sports Exerc, 34: 1262-1269, 2002.

2. Yang Y, Creer A, Jemiolo B, and Trappe S. Time course of myogenic and metabolic gene expression in response to acute exercise in human skeletal muscle. J Appl Physiol, 98: 1745-1752, 2005.

3. Wilborn CD, Taylor LW, Greenwood M, Kreider RB, Willoughby DS. Effects of

different intensities of resistance exercise on regulators of myogenesis. J Strength Cond Res, 2009 Nov;23(8):2179-87.

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