Full Body · Conditioning
Plank Jacks
Plank jacks are a conditioning exercise performed in a high plank, where you jump your feet out wide and back together, like a jumping jack, while keeping your upper body still. They train the core to hold a stable plank under a dynamic load and raise the heart rate quickly, combining abdominal work with cardio.
Also known as: Plank jack, Plank jumping jacks, Jumping plank jacks, Plank star jumps
- Muscle group
- Full Body
- Movement pattern
- Conditioning
- Type
- Compound
- Equipment
- None, Exercise mat
- Difficulty
- Beginner
What muscles does the plank jacks work?
Primary movers
- Rectus abdominis
- Transverse abdominis
- Hip abductors
Assisting muscles
- Shoulders
- Triceps brachii
- Calves
- Hip adductors
Like any plank, the core must stop the hips sagging. Plank jacks add a jumping lower body, so the abs have to hold position while the legs move quickly.
The hip abductors push the feet apart and the adductors bring them back together. These muscles work rapidly in an unusual position.
The shoulders and triceps hold the upper body up throughout, which makes plank jacks harder on the arms than many people expect.
The jumping motion raises the heart rate, turning a core exercise into a conditioning exercise.
How to do the plank jacks
Setup
- 1
Start in a high plank with hands under shoulders and body in a straight line.
- 2
Place your feet together.
- 3
Brace your abs and squeeze your glutes.
Execution
- 1
Jump your feet out wide, like the bottom of a jumping jack.
- 2
Immediately jump them back together.
- 3
Keep your hips level and in line with your shoulders throughout.
- 4
Land softly on the balls of your feet.
- 5
Keep the upper body still. Only the legs should move.
- 6
Continue for the set duration at a steady rhythm.
Common plank jacks mistakes
Hips bouncing
Letting the hips bounce up and down with each jump, which removes core tension.
The fix: Keep the hips level with the shoulders. Move more slowly if needed.
Hips sagging
Letting the lower back sag as fatigue sets in.
The fix: Squeeze the glutes, brace the abs and end the set when position breaks.
Shoulders drifting
Letting the shoulders move forward past the hands.
The fix: Keep the shoulders stacked over the wrists.
Heavy landings
Landing hard on flat feet, which jolts the body.
The fix: Stay light on the balls of your feet.
How many sets and reps?
| Goal | Sets | Reps | Load | Rest |
|---|---|---|---|---|
| Conditioning | 4–6 | 20–30 s | Bodyweight | 30 s |
| Core endurance | 3 | 15–20 | Bodyweight, controlled | 45 s |
| Beginner | 3 | 10 per side | Step-out plank jacks | 45 s |
Plank jacks fit well into HIIT circuits, core finishers and full-body conditioning sessions. Use 20 to 30 seconds of work with short rest. Beginners can step the feet out one at a time rather than jumping.
Running the plank jacks in your next block? Hercules logs every set, shows last session's numbers before you lift, and suggests when to add weight.
Get it on Google PlayPlank Jacks variations and alternatives
Plank
EasierThe static plank, building the core strength needed first.
Step-Out Plank Jack
EasierStepping each foot out one at a time removes the jump.
Jumping Jacks
AlternativeThe standing version, easier and focused on cardio.
Mountain Climbers
AlternativeA plank-based cardio exercise driving the knees instead of the feet out.
Frequently asked questions
What muscles do plank jacks work?
The abs and deep core muscles hold the plank, while the hip abductors and adductors move the legs. The shoulders, triceps and calves also work.
Are plank jacks good for abs?
Yes. They train the core to hold a stable plank while the legs move, adding a conditioning element to core training.
Are plank jacks cardio?
Yes. The jumping motion raises the heart rate, making them a useful cardio exercise in a HIIT circuit.
How do I make plank jacks easier?
Step the feet out one at a time instead of jumping, or perform them with your hands on a bench.
How long should I do plank jacks?
Intervals of 20 to 30 seconds work well. Stop when you can no longer keep your hips level.
Hercules tracks every plank jacks you log, shows you last session's numbers before you lift, and flags when your progress stalls.
Get it on Google Play