How fast should you lower the bar? What an 8-week tempo squat trial found
Thirty trained students squatted twice a week for eight weeks with three different lowering speeds. The four-second group got stronger and slower. The two-second group got stronger and faster. Here is what that means if you train slow on purpose.
Slow training people — us included — spend a lot of words defending the lowering phase. Control the eccentric. Do not drop the weight. Make the muscle work on the way down. All of that is well supported. What is far less discussed is the obvious follow-up question: how slow, and what do you give up at each speed?
A trial published in PLOS ONE in July 2026 (Hao, Qi, Zhao & Han, Shandong Sport University) put a number on it. Thirty sports-training students were randomised into three loaded back squat groups and trained twice a week for eight weeks. The only variable that differed between groups was the tempo of the lowering phase.
The three tempos
- 4/0/X/0 — four-second lowering, no pause, explosive intent on the way up, no pause between reps.
- 2/0/X/0 — two-second lowering, everything else identical.
- V/V/X/V — self-selected speed. Whatever felt natural on the day. The control most people accidentally run.
Before and after, the researchers measured maximal squat strength, countermovement jump height, squat jump height, and a 30-metre sprint.
What happened
Everyone got stronger. All three groups improved maximal squat strength significantly from baseline, and the differences between groups were not statistically significant. The effect sizes ranked 2-second (ES 1.45) above self-selected (0.85) above 4-second (0.64), but the honest reading is: for raw strength, any of these tempos works if you push hard enough.
The explosive results split the groups apart. The 2-second group improved countermovement jump (ES 1.07), squat jump (ES 1.09) and 30-metre sprint time (ES −0.76). The self-selected group barely moved. The 4-second group got measurably worse at all three: jump height dropped significantly (ES −0.90 and −0.83) and sprint times slowed (ES 0.63) — while their squat strength was still climbing.
The four-second group ended the study stronger and slower at the same time. Strength and speed came apart, and the only thing that separated them was how long the lowering phase lasted.
Why a slow lowering phase can cost you speed
Jumping and sprinting run on the stretch-shortening cycle: the tendon and muscle absorb a rapid stretch and return that energy in a fraction of a second. That reflex is trainable, and it is specific. Spend eight weeks teaching your nervous system to dissipate every stretch slowly and deliberately, and it gets very good at exactly that — which is the opposite instruction to the one a sprint start needs. This is not a failure of slow training. It is specificity doing what it always does.
It is also a narrow finding. Thirty young, already-trained sports students. Eight weeks. One exercise. Outcomes measured with jumps and sprints, not muscle biopsies or scans. It tells you something real about tempo and athletic transfer; it does not tell you slow training fails to build muscle — that question has a large and much more favourable literature behind it.
What this changes for a HIT trainee
If your goal is muscle, joint-friendly loading, and strength that carries into ordinary life, a slow honest cadence remains the right default. The study found no strength penalty at any tempo, and slow cadence is what makes a single set to failure controllable, measurable, and safe without a spotter.
If you also want to stay explosive — you play a sport, you ski, you sprint after a bus, you are training to keep the reflexes that prevent a fall from becoming a fracture — then the finding is worth acting on. Do not run every movement at a four-second-plus lowering for months on end. Keep one compound lower-body movement at a controlled two-second descent with intent to accelerate on the way up.
How we implemented it in Intense Fit
We added the Barbell Back Squat to the exercise library and placed it first in the Lower Split, where you meet it fresh and before the pre-exhaust pair. It ships with the study's cues built in — brace, roughly two seconds down, drive up with intent, no resting lockout — and a one-tap 3 / 2 cadence preset alongside the standard 3/3, 4/4, 5/5 and 10/10 options.
Cadence is per exercise, so you can run a 2-second descent on the squat and keep 5/5 everywhere else in the same session. Time under load is still tracked to the second, so you can see exactly what the faster descent costs you in TUL and adjust the load accordingly. And if barbells are not your thing, the squat is optional — hide it, swap it for the leg press, or build your own workout without it.
The proof
- Hao M, Qi H, Zhao L, Han W. The effect of squat training with different eccentric contraction tempos on lower limb muscle strength. PLOS ONE. 2026;21(7):e0354725. PMID 42507730
- Wilk M, Zajac A, Tufano JJ. The influence of movement tempo during resistance training on muscular strength and hypertrophy responses. Sports Medicine. 2021;51(8):1629–1650. doi:10.1007/s40279-021-01465-2
- Schoenfeld BJ, Ogborn DI, Krieger JW. Effect of repetition duration during resistance training on muscle hypertrophy: a systematic review and meta-analysis. Sports Medicine. 2015;45(4):577–585. doi:10.1007/s40279-015-0304-0
Read next: The slow cadence protocol, Time under tension, explained properly, Stop skipping leg day.
