Cardio · Beginner
AI High Knees Counter
High knees are a fast, no-equipment cardio move — you jog in place while driving each knee up toward hip height. They spike your heart rate in seconds, wake up your hips and core, and need barely any space, which makes them perfect for a quick break from your desk. REP RUSH counts each knee drive through your webcam so you can just go.
- In the app
- Counted for you
- Muscles worked
- Hip flexors, Quadriceps, Core, Glutes, Calves
- Equipment
- None (bodyweight)
- Also called
- running in place, high knee march, knee drives
How to do high knees with proper form
- 1 Stand tall. Start standing with feet hip-width apart, chest up, core braced, and arms bent at your sides.
- 2 Drive one knee up. Lift one knee up toward hip height in a quick, controlled motion, staying light on the ball of your standing foot.
- 3 Switch quickly. Lower that foot and immediately drive the other knee up, pumping your arms as if running.
- 4 Keep alternating. Continue alternating at a pace you can control while keeping the knees high. Each knee drive is one rep.
Muscles worked
Primary
Hip flexors, Quadriceps
Supporting
Core, Glutes, Calves
Common mistakes
Knees too low
Shuffling with low knees. Aim to bring each thigh up toward parallel with the floor.
Leaning back
Rocking your torso back to fling the knee up. Stay tall and lift with your hip flexors and core.
Landing heavy
Slamming your feet down. Stay light and springy on the balls of your feet to protect your joints.
Holding your breath
Forgetting to breathe on a cardio move. Keep a steady rhythm with your breath and your arms.
How many reps & sets
High knees are usually done for time or reps in bursts. Try 3–4 rounds of 30–50 knee drives (or 30–45 seconds), resting 30–60 seconds between rounds. As a quick desk break, even one hard 40-count round gets your blood flowing. Go faster for more cardio, slower and higher for more control.
High Knees FAQ
What muscles do high knees work?
High knees mainly work the hip flexors and quads that lift each leg, plus the core, glutes, and calves that keep you stable and springy.
Are high knees good cardio?
Yes. They raise your heart rate quickly and can be done in short, intense bursts, which makes them a great low-space cardio option for a quick break.
How high should my knees go?
Aim to bring each thigh up toward parallel with the floor — roughly hip height. Higher knees mean more hip flexor and core work.
Do high knees count as a workout?
In short bursts they're an excellent cardio finisher or standalone micro-workout. Stack a few rounds through the day to keep your streak and your heart rate up.
Count your reps, hands-free
REP RUSH watches through your webcam and counts every high knees rep on-device — no wearables, no signup, and your video never leaves your machine.
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