Low Reps or High Reps? Just Go to Failure, Bro
Mechanical tension drives muscle growth. Research shows that lifting a lighter load to failure produces gains in muscle size similar to those produced by lifting a heavy load to failure.
The scientific evidence on rep ranges tells us that there's no magical rep range for maximizing muscle size. You can use both heavy, low-rep (1-5) sets along with medium-load, high-rep (15-20+) sets if you'd like.
But many people focused on building muscle are usually not interested in using weights so heavy that they can only do five or fewer reps. And that's fine. Doing some sets in the 6-8 rep range serves as a nice middle ground.
But Keep Rep Quality in Mind!
The amount of weight you're using also determines the quality of reps you're doing. If the load is too heavy, you may not be able to do good, quality reps.
That said, at any given time at any big-box gym, you'll see at least one guy doing biceps curls or shoulder raises, and he'll have to thrust his lower back into it each time he brings the weight up.
It's easy to make this mistake. After all, you're in the gym to lift weights, and everyone knows heavy loads are an effective stimulus for muscle growth, right? Well, sort of.
Training to maximize muscle isn't about becoming a "weightlifter" as many seem to think. It's about using weights as a tool to increase your muscle size. Simply throwing as much weight around as you can to impress people is an ineffective approach.
Here's what happens when you use weights that are too heavy:
- You reduce the time under (mechanical) tension because you're forced to use momentum to cheat.
- You're unable to lower the weight slowly and with control, further reducing your time under (mechanical) tension.
- You use more muscles, which reduces the accumulated pump (metabolic stress) in muscles you're trying to target.
Training to maximize muscle isn't just about moving the weight from one point to another, as you would when weightlifting. It's about controlling the weight through the entire range of motion.
The point of emphasis on each rep is to avoid swinging the weight up or cheating by using other parts of your body to move the load.