Carving a defined pec line takes serious effort and consistency. The lower chest is often overlooked, and requires targeted movements using high-to-low pressing paths. That’s where the jackhammer pushdown comes in.

Spend enough time in the gym and you’ll eventually see someone hunched over a cable machine performing what looks like a poorly executed tricep extensions. Sometimes that’s exactly what it is. But in other cases, they’re doing jackhammer pushdowns – a movement that largely takes the triceps out of the equation and instead places significant emphasis on the lower chest.

On the surface, the exercise looks like a mix between triceps pushdowns and dips. But by flaring the elbows and leaning forward, the movement mimics the mechanics of a decline press, helping to better target the lower chest fibres through the direction of the movement.

‘If you follow the direction of the fibres when training the chest, you can more effectively target specific regions of the pectoral muscles,’ explains Athlean-X's Jeff Cavaliere. ‘In the sternal area of your chest, you have an additional head of the pecs called the abdominal head. It’s a small area that creates a break in the line of the lower pecs and then wraps underneath and around. It’s the lowest portion of the lower chest.

‘The fibres in this abdominal head run up and out at an angle from bottom to top towards your humerus. In this case, we need to choose lower chest exercises that take our arm down and across the chest.’ Here’s how to start building strength and size in that area.

Benefits of the Jackhammer Pushdown

1. Targeted Chest Hypertrophy

If you’ve never specifically trained your lower chest, you may see relatively fast progress at first. While bench presses and dips provide some stimulus, a more targeted movement can help drive development in the lower portion of the pecs.

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That said, body fat levels still play a major role in how defined your chest appears. No amount of pushdowns will create visible separation if overall body fat remains high.

‘There’s an important factor I want to mention which has a huge effect on the visual appearance of your chest,’ Cavaliere adds. ‘If you’re dealing with a high overall body fat level, it will be more difficult for you to see lower chest definition until you address that. You’ll need to focus on nutrition to lose fat and see what you’re really working with.’

2. More Freedom of Movement

Your arms don’t have to stay locked in a fixed path, allowing the movement to better match your natural mechanics. This can also reduce shoulder involvement, making it a useful option for those who struggle with pressing variations.

3. Strong Peak Contraction

Because you’re pressing straight down, you can focus on fully contracting the chest at the bottom of the movement. While not essential, this can help improve mind-muscle connection.

How to Do the Jackhammer Pushdown

  • Attach a straight bar to the highest setting on a cable machine and step one or two paces back.
  • Take an overhand grip, lean your torso forward and flare your elbows out to open up the chest.
  • Press the bar straight down, squeezing your chest as you lock out your arms.
  • Return the bar overhead, allowing your elbows to rise and your chest to open again. Repeat.

‘Don’t just stand there and bend and straighten the elbows, because that would work the triceps more than the chest,’ Cavaliere says. ‘Instead, open your chest by getting your elbows out to the side and letting them travel up. If they stay level, you’re doing it wrong. If they move up and down, you’re doing it right.

‘Then lean slightly forward over the bar so that when you press down, it becomes a close cousin to the dip.’