Squat and vertical jump: what strength-to-weight ratio you actually need

The squat helps your jump, but what counts isn't how much you lift in absolute terms: it's how much you lift relative to what you weigh. A 70 kg athlete and a 95 kg athlete putting up the same bar do not have the same usable strength for leaving the ground. And past a certain point, adding more plates stops giving you centimetres. Here's why.

Why the number on the bar tells you nothing on its own

When you jump, the load you have to move is you. Your legs have to accelerate your own body upwards, not an external weight. So the useful question isn't "how much do you squat", it's "how much force do you produce for every kilo you have to lift".

That's why the sensible reference is the strength-to-weight ratio: the load you can move divided by your bodyweight. A light athlete with a good relative squat often has an advantage in the jump over a heavier athlete with the same absolute squat.

This has a practical consequence that catches a lot of people off guard: adding load by putting on weight can leave the ratio unchanged, or make it worse. If you gain five kilos and your squat barely moves, from the jump's point of view you've gained nothing. Quite the opposite.

How far strength keeps giving you centimetres

Base strength works like a foundation. If you don't have much, it's the bottleneck: you can do all the plyometrics you like, but you don't have enough push to express quickly. In that phase, every kilo added to the squat tends to turn into jump height.

Then comes a point where strength stops being the problem. Not because it's useless, but because the limit has moved somewhere else: to the speed at which you can express it. In a jump you have a fraction of a second of contact with the ground. It doesn't matter how much force you could produce if you had three seconds: what matters is how much you produce in the time you actually have.

From there on, just loading the bar is time badly spent. You need specific work on how fast you express that strength: measured plyometrics, jumps, and methods that pair a heavy load with a fast movement, like the contrast method.

How to work out which phase you're in

You don't need a lab. Two honest observations are enough:

• Do you struggle to control your own bodyweight? If a bodyweight lunge or single-leg squat makes your knee cave inwards, base strength is still your limit. Work there.
• Strong in the gym but "slow" on the floor? If you lift respectable loads but feel heavy when you jump, with your foot staying on the ground too long, the problem isn't strength any more: it's speed.

When in doubt, the almost always correct answer for a young or lightly trained athlete is: build strength first. It's the most boring phase and the most skipped, and it's the one that holds up everything else.

The squat alone is never enough

Even in the phase where strength is the bottleneck, the squat isn't the programme: it's one piece of the programme. The jump is a movement where ankle, knee and hip work together in a precise sequence, with the arms contributing more than people think.

An athlete who does nothing but heavy squats tends to get strong in a slow, controlled position that looks very little like the real movement. You also need single-leg work, ankle drive, and jumps done properly with adequate recovery.

The opposite holds too, and it's the most common mistake among volleyball players: only jumps and plyometrics, zero strength. Typical result, knees that start hurting and a jump that stops improving after a few weeks.

Before deciding where to work, measure

You can argue for months about whether you're missing strength or speed. Or you can start from a number and see what happens when you change your training. With the JHP jump test you upload a 2-second video and get your height in centimetres from flight time: free, the analysis runs in your browser and the video never leaves your device.

Then run a serious block of work, keep track of your loads and measure again. If your jump goes up while your squat goes up, you're in the phase where strength pays. If the squat goes up and the jump stays put, you have your answer: it's time to work on speed.

The JHP programmes, depending on where you're stuck

• JHP Gym Edition — 16 weeks in the weight room, €60. If your limit is base strength.
• JHP Contrast Method — €90. If you're already strong and need to turn that strength into fast push.
• Jump Higher Program — 10 weeks bodyweight, €60. If you don't have access to a gym.
• JHP Subscription — €99/year: 13 programmes, WhatsApp support, cancel anytime. Full list on the JHP courses page.

In short

The squat counts, but relative to your bodyweight and only up to a point. As long as base strength is the bottleneck, every extra kilo shows up in your jump. Once the strength is there, the limit becomes the speed at which you express it, and that takes a different kind of work. The only way to know which phase you're in is to measure your jump and watch what happens when you change your training.

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