There are only so many ways you can curl a dumbbell. Rather than changing things like tempo or grip, most lifters simply try to go heavier or do more reps to stimulate new growth. But this nearsighted approach isn't helping their gains.

With the curl being such a small movement, it doesn't take long before your biceps need new stresses to adapt and grow. Ask yourself this:

• When's the last time you increased the weight in curls?
• When's the last time you did anything other than 3 sets of 10?
• When's the last time your arms actually grew?

Hypertrophy is caused by an adaptive response from stress, making our muscles grow bigger. If you're not introducing new stresses in one way or another, whether it's lifting heavier or changing the tempo, you won't get any better.

Here's one way to stress-out your biceps:

The Isometric Curl Drop-Set

Use this as a finisher on your upper-body workouts. Choose a weight you can strictly curl for 20 reps. You can use dumbbells or a barbell.

1. Curl the weight to 90 degrees and hold for 10 seconds. Then do 10 full-range of motion curls. Rest 40 seconds.
2. Curl the weight up to 90 degrees and hold for 8 seconds. Do 8 curls. Rest 30 seconds.
3. Curl the weight up to 90 degrees and hold for 6 seconds. Do 6 curls. Rest 20 seconds.
4. Curl the weight up to 90 degrees and hold for 4 seconds. Do 4 curls. Rest 10 seconds.
5. Curl the weight up to 90 degrees and hold for 2 seconds. Do 2 curls.