Luke Zocchi is the trainer responsible for keeping Chris Hemsworth in superhero shape. And, if you've ever seen any of the Thor films, it's clear he's very good at his job. He's also a leading trainer for Centr, Hemsworth's venture into the world of the best fitness apps.
The app recently launched a 28-day arm workout challenge, with Zocchi leading the first workout – a six-minute session that targets the biceps with just a couple of dumbbells. So, as TechRadar's resident fitness guinea pig, I decided to take it for a spin.
"I'm going to be using the Smart Stack [Centr's new adjustable dumbbells, which are reduced in the Amazon Prime Day sale] but you can just use a normal set," Zocchi says.
Because they allow you to change their weight to suit the exercise you're doing, adjustable dumbbells are a brilliantly versatile tool for sans-gym strength training. But for this workout, I thought I would be able to complete it with a single low-tech set of 30lb fixed weight dumbbells. So I scooped them up and set to work.
How to do Chris Hemsworth's trainer's six-minute arm workout
- Dual dumbbell biceps curl x30 seconds
- Rest for 20 seconds
- Alternating dumbbell biceps curl x30 seconds
- Rest for 20 seconds
- Alternating to dual dumbbell biceps curl x40 seconds
- Rest x30 seconds
- Dual dumbbell hammer curl x30 seconds
- Rest 20 seconds
- Alternating dumbbell hammer curl x30 seconds
- Rest 20 seconds
- Alternating to dual hammer curl x40 seconds
1. Dumbbell biceps curl
- Stand upright with your feet shoulder-width apart, your chest up and a dumbbell in each hand. Your arms should be extended at your sides, with your palms facing forward.
- Keeping your elbows back, explosively curl the dumbbell up to your shoulder, pause for a split-second, then slowly control it back down to the starting position.
- For the dual dumbbell biceps curls, do this with both arms at the same time, and for the alternating variation do this with one arm at a time.
- For the alternating to dual version of this exercise, perform one repetition with your right arm, one repetition with your left arm, one repetition with both arms, then repeat this sequence.
Zocchi's top tips:
"We're going to focus on tempo, so you're going to explode up fast [toward the shoulder] then control the weight down for one second," says Zocchi.
"If your [arms are] swinging too much, you probably have too heavy a weight, and you need to bring that weight down."
2. Dumbbell hammer curl
- Stand with your feet shoulder-width apart and your chest up, holding a dumbbell in each hand. Your arms should be extended by your sides with your palms facing inward.
- Keeping your elbows back and pinned to your side, curl the dumbbell up to your shoulder, pause for a split-second, then lower it back to the starting position.
- For the dual dumbbell hammer curls, do this with both arms at the same time, and for the alternating variation do this with one arm at a time.
- For the alternating to dual version of this exercise, perform one repetition with your right arm, one repetition with your left arm, one repetition with both arms, then repeat this sequence.
Zocchi's top tips:
"Normally you will be a bit stronger in this lift, so I'm going to increase my weight [for it]," Zocchi says. "But you can stay at the same weight because you could have fatigued a little bit within [the first part of] this workout.
"We're using the same tempo, exploding up, one-second down, and pausing for a second [at the bottom] as well.
"…Always control that weight, that's going to activate muscle growth, and having that one-second pause between reps is going to slow down the momentum so your biceps are going to have to work harder."
He adds that this exercise strengthens your forearms, as well as your biceps.
My experience tackling Chris Hemsworth's trainer's six-minute arm workout
'Who doesn't like to train biceps?' an ever-chirpy Zocchi says as he grabs his dumbbells in preparation for the workout ahead.
I'm following the routine on the Centr app, which takes care of the workout's timings and makes me privy to Zocchi's steady stream of handy technique tips. However, while it's a bit of extra effort, the stopwatch on your phone will work as a timer for this routine too.
The first two sets of curls feel good, and reaffirm my choice of dumbbell weights – they feel challenging and my muscles are starting to burn by the end of each set, but I'm able to work for the full 30 seconds while maintaining Zocchi's desired form and tempo.
However, the third curl variation fires my arms up to new levels, and I find I have to fight the urge to swing my arms in a desperate attempt to give my biceps an easier ride.
The switch to hammer curls comes at just the right time (Zocchi says most people "will be a bit stronger in this lift"). However, because my biceps are already toasted, I decide to tactfully ignore his suggestion to up the weight and instead stick with my trusty 30lb dumbbells.
By this point in the workout, the short rest periods had created an intensity that sent my heart rate skyward, so much so that I could feel sweat beading on my brow. And when I came to the final set, my arms were on fire.
I stuttered to the finish line with questionable form on my final few reps. However, my efforts were rewarded when a quick glance in the mirror revealed this quick hit had delivered an enjoyably ego-boosting arm pump.
So, if you're after a fast, fun session to squeeze into a busy day, or you're looking for some supplemental arm-targeting exercises to tag on the end of your regular workout, I'd definitely recommend giving this one a go.
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