Part of these sets

This exercise rarely works alone. It appears in the following routines, where it is sequenced alongside the others that support it.

What it works

Primary muscles

Quadriceps
Gluteus maximus

Also involved

Gluteus medius, stopping the pelvis dropping on the free side
Calf muscles of the leading leg

Equipment: A stair, a low sturdy box or an aerobic step, with a rail or wall within reach.

How to do it

1
Stand facing the step, close enough that your toes almost touch it, with a rail or wall beside you.
2
Place one whole foot on the step, not just the ball of the foot, and settle your weight over it.
3
Push down through that leading heel and stand up onto the step, letting the leg on the step do the work rather than the toes of the trailing foot.
4
Bring the trailing foot up to join it, or leave it hovering just off the step for a harder version.
5
Step the same foot back down slowly over three seconds, touching the floor lightly with the toe. The leg still on the step is doing the lowering.
6
Complete all the repetitions on one leg before swapping, so the working leg gets a proper set.

How much to do

3 sets of 8 to 10 each leg

2 to 3 times a week, with a rest day between

Discomfort up to about four out of ten during the exercise is acceptable if it settles within 24 hours. If the knee is sorer the next morning, lower the step rather than dropping the exercise.

Stop and get assessed if

Stop and get assessed if the knee gives way, locks or swells after step ups, or if sharp pain at the front of the knee does not ease when you lower the step. A step that rocks or slides underfoot is not a training problem, it is a hazard, so change it before you use it.

Common mistakes

Pushing off the back foot: The trailing leg quietly does the work and the leg you meant to train barely loads at all. Lighten the back foot until you can lift its toes before you start, and you will feel the difference immediately.
Dropping down off the step: The descent is the half that builds control, and it is the half stairs actually demand. Falling off the step trains nothing and lands full body weight on a joint that was not ready for it.
Choosing a step that is too high: A high step forces the knee into deep bend under full body weight, which is where a sore kneecap complains most. Ten to fifteen centimetres is a genuine starting point, and the height is what you progress.
The knee collapsing inwards and the opposite hip dropping: That collapse increases stress across the kneecap and usually means gluteus medius is lagging. Use a mirror, keep the pelvis level and the knee over the middle of the foot, and add side lying hip work alongside.
Hauling on the rail: Fingertips for balance are fine, pulling with the arm is not, because it removes the load you came for. Progress from a grip, to fingertips, to hands hovering.

Making it harder

Raise the step height gradually as control allows.
Hold a weight in each hand, or wear a loaded rucksack, and build the load over weeks.
Step downs: start standing on the step and lower one foot slowly to the floor, which is the harder direction and the one that hurts on stairs.
Pause for two seconds with the trailing foot hovering at the top, which adds single leg balance work to the same repetition.

Making it easier

Use a lower step, even a single five centimetre block. Height is the dial, so build that before you build repetitions.
Keep two fingers on a rail or the wall throughout and reduce the contact over the following weeks.
Do fewer repetitions with a proper rest between them. Six clean step ups beat twelve where the last six collapse inwards.

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