Box Jumps: How to Do Them, Muscles Worked and Box Height
How to do a box jump safely, which muscles it works, how to pick your box height, why you should step down not jump down, and a sensible sets and reps plan.
By Mike Shilling, Recovery & Training Editor · Updated 7 August 2026
Tight calves are the quiet reason a lot of training goes sideways. Your heels lift in a squat, your ankles stop you sitting into a lunge, your Achilles grumbles after a long run, and the culprit is a pair of muscles you have barely thought about since school. The good news is that calves respond well to stretching, provided you actually stretch both of them and hold long enough for it to count.
Here are six stretches worth your time, what each one targets, and the honest limits of what stretching can and cannot fix.
Your calf is really two muscles stacked on top of each other, and they need different treatment.
The gastrocnemius is the visible one, the diamond-shaped muscle that gives a calf its shape. It crosses both the knee and the ankle, which is the important detail: bend your knee and it goes slack, so any stretch that lets your knee bend misses it entirely. Straight back leg, every time.
The soleus lies underneath, flatter and broader, and it only crosses the ankle. That means the only way to reach it is with your knee bent, which is exactly the position most people never stretch in. If you have been doing wall calf stretches for years and your ankle mobility has not moved, an untouched soleus is the usual explanation.
Both feed into the Achilles tendon, and both limit ankle dorsiflexion, the motion of pulling your toes towards your shin. That single range of motion determines how deep you can squat with your heels down, how well you absorb landing forces, and how much your knee travels forward when you run.
What stretching realistically buys you
Be honest about the size of the effect. A systematic review of static stretching for ankle dorsiflexion found a statistically significant improvement, with individual trials reporting gains of roughly 2 to 8 degrees over control groups (Young and colleagues, 2013). That is a real, useful change, and it is also not a transformation. Most trials ran under four weeks, so the long-term picture is thinner than anyone would like.
The classic, and still the best starting point.
The most common mistake is letting the back knee soften. The instant it bends, the gastrocnemius relaxes and you are stretching almost nothing.
Same setup, one change, completely different muscle.
Start in the wall calf stretch position, then bend the back knee while keeping that heel glued to the floor. The pull moves down and deeper, closer to the ankle and the top of the Achilles. It feels less dramatic than the straight-leg version, which is why people skip it, and it is usually the one that actually unlocks a stubborn squat.
Hold 30 seconds each side. If you feel nothing, shorten your stance: the soleus stretch works at a much smaller distance from the wall than the gastrocnemius version.
Stand on a step with the balls of both feet on the edge and your heels hanging off. Hold the rail, keep your legs straight, and let your heels sink below the level of the step under your own bodyweight. Hold 30 seconds, then do a second round with your knees softly bent to catch the soleus.
This one gives you a deeper stretch than the wall version because gravity does the work and you can control the load precisely by shifting weight onto one leg. It is also the easiest to overdo, so ease into the bottom position rather than dropping into it.
From a press-up position, push your hips up and back into an inverted V with your hands and feet planted. Straighten one leg and press that heel towards the floor while the other knee bends, then swap, alternating slowly like you are pedalling.
The pedalling version is more useful than holding both heels down, because the one-leg-at-a-time loading reaches further and the movement keeps blood in the tissue. Thirty seconds of slow alternating per side is plenty. A decent yoga mat makes this considerably less unpleasant on hard floors.
Kneel on one knee with the other foot flat on the floor in front of you, front shin roughly vertical. Keeping that front heel pinned down, drive the knee forward over and slightly outside the toes until you feel a pinch or stretch at the front of the ankle and a pull in the back of the calf. Rock in and out of it ten to fifteen times, then hold the end position for 20 seconds.
This is the most specific drill on the list for the ankle range you need in squatting, and it is worth doing before lower body sessions. If you want to make it harder, loop a resistance band around the front of the ankle and anchor it behind you to pull the joint back as you rock forward.
Sit on the floor with one leg straight out, loop a towel, belt or strap around the ball of that foot, and pull the toes back towards you while keeping the knee flat. Hold 30 seconds.
This is the one to use if standing stretches aggravate a sore Achilles or if you are stretching in bed, on a plane, or anywhere you cannot get a wall. It is gentler than the weight-bearing versions and easier to control, though it reaches less far.
Stretching calves works on a boring schedule rather than a heroic one. Two rounds of the wall stretch and two of the bent knee version, both sides, takes four minutes and covers the essentials. Do it after training or in the evening, five to seven days a week, and reassess after a month.
Keep the long holds away from the start of a run or a jumping session. Static stretching immediately before explosive work can blunt power for a short window, so warm up with movement instead: ankle circles, walking lunges, a few calf raises through a full range, and some easy skipping.
One more thing worth saying plainly. Tight calves are very often weak calves. If yours stiffen up again within hours of stretching, the tissue is probably asking for strength rather than length, and slow, heavy calf raises with a pause at the bottom will do more than any amount of stretching. The NHS recommends muscle-strengthening work covering all the major muscle groups on at least two days a week, and your calves count.
Foam rolling sits alongside stretching rather than replacing it. Rolling the calf for a minute before you stretch often lets you reach a bit further in the stretch itself, which is worth the extra ninety seconds if you own a foam roller already. Ankle mobility also pays off directly in the squat, where limited dorsiflexion is the usual reason heels lift and depth stalls (review of the deep squat and the knee joint).
Thirty seconds per side is the sweet spot for a single hold, repeated two or three times. Anything under fifteen seconds does very little, and holds beyond about a minute stop adding much. If you want a lasting change in ankle range rather than a temporary loosening, the total weekly volume matters more than any single hold, so aim for a few minutes per calf spread across the week.
The gastrocnemius crosses both the knee and the ankle, so you stretch it with your back leg straight. The soleus sits underneath it and only crosses the ankle, so you have to bend the knee to reach it. Most people only ever do the straight-leg version and leave the soleus permanently short, which is why their heel still lifts in a deep squat.
Usually some mix of footwear with a raised heel, long hours sitting, a sudden jump in running mileage, and calves that are weak rather than genuinely short. Tightness is often a strength problem wearing a flexibility costume: a calf that cannot control the load asks for help by staying stiff. Pair your stretching with calf raises and see whether the feeling changes.
After, or on a separate day. Long static holds immediately before running can briefly reduce power output, so keep the pre-run work dynamic with ankle circles, walking lunges and a few easy skips. Save the thirty second holds for after the session or the evening, when the tissue is warm and you are not about to ask it for force.
Calf stretching is part of the standard advice for both, and reduced ankle dorsiflexion is a recognised risk factor. But stretching alone rarely does it. Loading the tendon progressively with slow, heavy calf raises does more of the work, and persistent heel or Achilles pain deserves a physiotherapist rather than another fortnight of guessing.
Daily if they are properly tight, five days a week if you are maintaining. Consistency beats intensity here by a wide margin. Two minutes before bed, every night, will do more over a month than one heroic twenty minute session on a Sunday.
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