Ask a kindergartener to show you her muscles, and she'll flex her biceps. Hand a dumbbell to a 10-year-old boy, and the first thing he'll do is a curl. Look around your gym on a typical day, and chances are at least half the people—male and female, young and old, lardy and lean—will be doing curls and extensions at any given moment.
You'd think, with all the time and attention we devote to our biceps and triceps, we'd know the best way to make them bigger and stronger than they are now. But three recent studies suggest we may know less than we think about building our favorite muscles.
Study #1: Split the difference
Let's start with a notion accepted by just about anyone who's read a bodybuilding magazine: If you want bigger arms, you have to devote entire workouts to training them.
According to this philosophy, total-body workouts, in which you work all your major muscles, are fine for beginners. But as you get more experienced and ambitious, you have to switch to split routines.
So you might have separate workouts for your back and biceps and chest and triceps, with other workouts that hit shoulders, abs, and lower-body muscles. In the most advanced programs, you might hit each muscle group just once a week.
A study in the July issue of The Journal of Strength and Conditioning Research put that idea to the test. The researchers recruited 20 experienced lifters and had them train three times a week for eight weeks. Half did split routines (chest and back; lower body; shoulders and arms), while the other half did total-body workouts. The programs were matched for total sets and reps, and the exercises were the same.
It's worth emphasizing that these guys were young (23, on average) and strong.
"There was a fairly wide spectrum of physiques, but the majority of them were pretty jacked," says Brad Schoenfeld, CSCS, author of The Max Muscle Plan and the study's lead investigator.
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All of them gained muscle. All of them got stronger. The surprise is that those doing the total-body routines got better results across the board. This was especially true for biceps thickness: It increased 8 percent for the total-body group, who did just two sets of curls each workout, vs. 5 percent for the guys doing split routines, who did all six sets on the same day.