The science of
squatting

Squats are the most universal exercise there is, which means they attract the most nonsense. Here is what the research actually supports for the three things a squat is actually used for — mobility, metabolism and strength — and, just as usefully, which popular squat claims fall apart when you read the papers.

Three jobs, not one

A squat is used for three fairly different things, and the evidence is strongest in a different place for each. Sorting them out first saves a lot of arguing.

• The bottom position, held — a deep squat hold, used as mobility work and as an alternative to sitting in a chair.
• Reps, done often and briefly — the metabolic tool, and the one with a surprisingly concrete number attached.
• Reps, done to near failure — the strength and muscle tool.

A fourth exercise, the wall sit, has better evidence than any of them for one specific outcome — but it is not a squat, and we keep it separate for that reason. More on that below.

Reps build muscle, even without weights

The objection to bodyweight squats is that they are too easy to build anything. The evidence disagrees, with one condition: you have to get close to failure. A meta-analysis of low- versus high-load training found that light loads taken to muscular failure build muscle comparably to heavy loads.² A six-week randomised trial in sedentary women put a ten-step bodyweight squat progression against barbell back squats at 60–80% of one-rep max; both groups significantly improved leg girth and strength.³

The dose is smaller than most people assume. Two sets taken near failure, twice a week, satisfies the World Health Organization’s muscle-strengthening guidance — activity for all major muscle groups on at least two days a week, which an estimated 10–30% of adults actually manage.⁴ More helps you progress faster. It is not required to get the health benefit.

Holds build something different

An isometric hold is not a worse rep. It is a different stimulus with its own quirk: strength gains concentrate around the joint angle you trained. Hold at 90° and you get strongest near 90°. That specificity is the argument for doing both — and for holding at more than one depth if holds are all you do.

Holds do build size. Reviewed isometric protocols report muscle cross-sectional area gains of roughly 5–23% across 6–14 weeks, biggest when the hold is at a long muscle length and done with real intent rather than a passive lean.⁵ That range is wide because the protocols behind it are wildly different, so read it as “this genuinely works”, not as a prescription. Which to pick, and when →

Ten squats can move your blood sugar

This is the most immediately useful thing in the whole literature for anyone with a desk, and it is about actual squats. In a randomised four-arm crossover in 18 overweight and obese men, 10 bodyweight squats every 45 minutes brought the post-meal glucose response down from 10.2 to 7.9 mmol/L/h — about 23% lower than sitting through the same 8.5 hours. That exactly matched a 3-minute walk every 45 minutes, and beat a single continuous 30-minute walk (9.2).⁶

The mechanism is the interesting part. Energy expenditure was matched across all four conditions, so this is not calories — and of everything measured, only quadriceps and gluteal muscle activity predicted the glucose reduction. The contraction itself is doing the work.

It is still a small, acute study. But it sits inside a consistent body of “activity snack” research: bodyweight chair stands match volume-matched treadmill walking for lowering post-meal insulin,⁷ and squat breaks every 30 minutes improved how much of a meal’s protein actually reached muscle.⁸ The desk protocol →

Chairs are the anomaly, not squatting

Hadza hunter-gatherers in Tanzania are non-ambulatory for about 9 to 10 hours a day — roughly what an office worker manages. The difference is posture. They spend about two of those hours squatting or kneeling, and EMG shows those postures hold leg-muscle activity at 20–40% of walking levels, against about 5% for sitting in a chair.⁹

The honest reading: this is a real, measured difference in muscle activity during rest, and a genuinely interesting hypothesis about why human bodies tolerate rest badly in chairs. It is not proof that squatting instead of sitting prevents disease — that leap is correlational and tangled up with everything else about how the Hadza live. The deep squat hold →

Squats are not wrecking your knees

A 2024 scoping review of deep squats and knee joint structures found 13 of 15 studies affirmed the safety of deep squatting in healthy people. Cartilage appears to adapt to the load by thickening, and past 90° of knee flexion the patellofemoral contact area gets larger, spreading force over more surface rather than concentrating it.¹⁰

The companion myth — never let your knees pass your toes — traces to a single paper from 1961 and has not held up. Blocking forward knee travel does not remove load, it relocates it to your hips and lower back. The variable actually linked to knee injury is knees caving inward, which is a different plane of motion entirely.¹¹ The full knee picture →

Getting out of a chair predicts things

Chair-stand performance — a squat, essentially — is inversely associated with all-cause and cardiovascular mortality in older adults, in a study spanning 28 countries and 18,252 people.¹² In the Toledo Study for Healthy Aging, men with low relative sit-to-stand power carried a 57% higher all-cause mortality risk.¹³

Both are observational. A slow chair stand is a marker of overall frailty, and nobody has shown that training the movement changes the mortality number. It is a good reason to care about leg strength as you age; it is not a promise. Squats after 60 →

The adjacent exercise with the best evidence

Here is the honest situation. The strongest single piece of exercise evidence anywhere near this subject is not about squats at all. Pooling 270 randomised trials and 15,827 people, isometric holds lowered resting blood pressure by 8.24/4.00 mmHg — ahead of aerobic exercise (4.49/2.53), resistance training (4.55/3.04), combined training (6.04/2.54) and HIIT (4.08/2.50). The single best-ranked exercise of the lot was the wall squat.¹

And to be explicit about the gap this leaves: there is no comparable trial base showing that an unsupported squat hold lowers blood pressure. It is an isometric, so it is a reasonable guess. A reasonable guess is not a finding.

What we are not going to claim

Where squattime fits

Every number above assumes the squat actually happened. A quarter-squat is not a squat with less benefit — for glute and adductor activation it can deliver less than half the output of a full-range rep,¹⁶ and it is not what any of these studies measured. squattime counts a rep only when your hips reach the knee line, and times a hold only when the camera can see the geometry. That is the whole reason it exists: the number means something.