Dumbbell curls are a common alternative to the barbell on biceps day, but most trainers do them in a way that partially undermines their effectiveness. How? Let’s take a look.
When alternating arms in such a way that you do a complete rep (contraction/extension) for one side before switching to the other, you insert a three-second-or-so rest period at the bottom of each rep on each side. That means that what you think is a single set of 10 reps is rather 10 sets of 1 rep, each separated by some three seconds. Certainly, that’s one way to train, but all the scientific research relating to set construction points to you doing a single set using a weight in which you reach failure between 8 to 12 reps to maximize hypertrophy, so long as you keep constant tension on the muscle. In fact, if you dig deeper into the research, that set should be 40 to 60 seconds in total time under tension (TUT) to optimize musclebuilding processes. TUT means no rest periods to break up demands on the target muscle. (It also suggests that if you allow a weight stack to touch down between reps on machine movements, you’re repeating that mistake here, too.)
What’s a better way? Easy: do both arms simultaneously! Other options: do all reps for one side first before switching to the other, or hold the dumbbell not by your side at the bottom of the rep, but isometrically in the peak-contracted (up) position instead while the opposite side is working – just don’t pull your elbows forward from your sides, because that releases tension on the muscle! Another option is to keep both sides moving all the time. When you’re contracting one bicep, the other is extending, so there’s no rest stop! This applies to hammer curls, too.
As for pushing past failure, try this: do both arms simultaneously and when fatigue sets in, start alternating sides. This not only allows you to use a bit of momentum, but it also gives the opposite side a bit of a break between reps.
Go ahead and do alternating dumbbell curls on occasion, but for the most part, stick to methods that have a better track record of success!
