By Paul Kendrick, Cardio & Endurance Editor · Updated 8 September 2026
High knees look like jogging on the spot and are not. The whole point is the height: driving each thigh up to hip level, fast, while your torso stays upright and your foot lands under you rather than in front. Get that right and you have a warm-up that prepares you for sprinting, a conditioning tool that spikes your heart rate in twenty seconds, and a drill that quietly exposes how weak most people's hip flexors are. Get it wrong, which most people do, and you have a shuffle with a lean.
No kit required, though a mat helps if you are on a hard floor.
The one cue that fixes bad high knees
Put your hands out flat at hip height and touch your thighs to your palms each rep. It gives you an immediate, honest target, and it makes leaning back pointless because your hands move with your body. Most people discover their knees were about 15cm lower than they thought.
They raise your heart rate faster than almost anything. Twenty seconds of proper high knees will have you breathing hard, which makes them a useful interval piece with no equipment and no space. Short-format high-intensity interval work improves cardiorespiratory fitness and body composition in recreationally active adults (HIIT effects on fitness and body composition), and high knees are one of the easiest ways to build a session like that in a living room.
They prepare you to run. The pattern is running mechanics slowed down and exaggerated: knee drive, foot under the hip, upright posture. That makes them a far better pre-run warm-up than static stretching.
They fix a hip flexor weakness you did not know you had. Sitting all day shortens and weakens the hip flexors, and most people cannot hold hip-height knee drive for thirty seconds. That is worth training in its own right.
They cost nothing and need a metre of floor. Which matters more than it sounds, because the workout you do is worth more than the one you skip. They fold neatly into any bodyweight circuit alongside mountain climbers and jumping jacks, and they count towards the NHS target of 150 minutes of moderate or 75 minutes of vigorous activity a week (UK physical activity guidelines).
Knees too low. The default failure. If your thighs are not getting near parallel, you are jogging on the spot with extra effort. Use the hands-at-hip-height test and accept a shorter, better set.
Leaning back. People lean away to create the illusion of height, which shifts the work off the hip flexors and onto the lower back. Stay vertical even if the knees drop.
Landing on the heels. Heavy heel contact rattles your shins and kills any elasticity. Stay on the balls of your feet and think quiet.
Reaching the foot forward. The foot should come down under your hip, not out in front. Landing ahead of your centre of mass brakes you on every step and makes the whole thing feel like wading.
Lazy arms. Arms hanging or flapping across the body slow the legs down and cost you the rhythm. Drive them, elbows at 90 degrees, straight forward and back.
Going too long. By 45 seconds the knee height has usually collapsed and you are grinding out a worse version of the exercise. Stop while the form is still good and take another bout instead.
As a warm-up: 3 rounds of 20 seconds at moderate speed, 40 seconds walking, before a run or a leg session.
As conditioning: 8 to 10 rounds of 20 seconds hard, 40 seconds rest. That is a real session and it takes ten minutes.
In a circuit: 30 seconds of high knees between strength exercises, or paired with burpees and press-ups for a no-equipment finisher.
If you are training on a hard floor, put something under you. A decent exercise mat cuts the impact and the noise, and for anyone wanting the same heart rate spike with a lower thud a skipping rope does a similar job. There is more bodyweight work in the workouts section.
Hip flexors do the lifting, calves and glutes do the springing, and your quads and hamstrings handle the switch between the two. Your abs work harder than people expect, because they stop your lower back arching every time a knee comes up. It is a lower body drill with a genuine core cost.
Thigh parallel to the floor, or as close as you can hold without your torso leaning back. Hip height is the target and most people quietly settle for waist height while leaning away, which trains nothing useful. Lower knees done properly beat high knees done badly.
Yes, when you go hard. Done at proper speed they push you into interval territory quickly, and short bouts of high-intensity interval work reliably improve cardiorespiratory fitness. Done at a gentle jog on the spot, they are a warm-up and nothing more.
20 to 40 seconds per bout if you are training them hard, with equal or longer rest. Past about 45 seconds most people lose the knee height and the posture, and once the form goes the exercise stops being what you started.
Not specifically. Nothing targets fat from one area. High knees burn calories at a decent rate and raise your heart rate quickly, which contributes to overall fat loss when your diet supports it, but spot reduction is not a thing.
The name is misleading. Your knee joint does very little work here since the load is at the hip and the ankle. If anything hurts it is usually the front of the hip from tight hip flexors, or the shins from landing heavily on the heels.
With care. It is a running-in-place movement and it transmits sound downwards. Land quietly on the ball of the foot, put a mat down, and if that is still a problem swap in a low-impact alternative.
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