Cut the set at 10% velocity loss: half the reps, and the power survives
In short
Three sets at 60% of one-rep max, stopped either when bar velocity dropped 10% from the first rep or when it dropped 20%. Total repetitions differed twofold — about 12 versus about 24 — and blood lactate rose 11% versus 29%. The decisive difference was power: after the 10% protocol, chest press peak power was 3% higher than before training; after the 20% protocol it was 4% lower. Blood pressure and heart rate showed no difference between the two.
There are three ways to decide where a set ends: hit a rep target, go until you cannot lift another, or stop when bar speed drops by a set percentage. The third is velocity-based training, and this study ran the same people through two thresholds — 10% and 20% velocity loss — a week apart.
Everything else was identical: chest press and leg press, 60% of one-rep max, three sets. Only the stopping rule changed. Total repetitions came out at roughly 12 versus roughly 24. Pushing the threshold ten percentage points later doubled the volume of the session.
How much did lactate differ?
Blood lactate rose 11% versus 29%. Given twice the reps, that is unsurprising — but lactate is rarely the goal of a training block. The question is what it cost.
Why did power move in opposite directions?
The fastest velocity and peak power against a fixed weight were recorded before and immediately after each protocol. On chest press, the 10% condition finished with peak power 3% higher and velocity 2% higher than at the start. The 20% condition finished 4% lower on both. Cutting sets early left the body moving better than when it walked in; cutting them late left it moving worse.
What about cardiovascular load?
Systolic and diastolic blood pressure and heart rate showed no significant difference between protocols. Twice the reps and nearly three times the lactate rise produced a comparable acute cardiovascular response. On these measures there was no reason to cut reps out of caution.
So which threshold should you use?
It depends on the block. If you want to train often while keeping power and speed intact, 10% leaves you in better shape at the end of the session. If you are in a phase that needs accumulated volume, 20% gives you twice the reps in the same time. The practical answer is to assign each threshold to a phase rather than picking one forever.
Measuring velocity takes equipment, but the logic of the rule does not. The first rep that visibly slows down is roughly where that boundary sits. The volume-intensity balance is covered in training volume versus intensity. If you are chasing a score derived from one-rep maxes, preserving power raises the starting point of the next session.
Participants were 29 older adults averaging 81 ± 8 years. The size of the power loss will not transfer directly to younger lifters with more recovery capacity. The direction — cutting sets later leaves output lower after the session — is reported consistently across age groups, but these particular numbers belong to this population.
Frequently asked questions
Is 10% or 20% velocity loss better?
It depends on the goal. The 10% threshold produced half the total reps but finished the session with peak power 3% higher; the 20% threshold doubled the reps but left power 4% lower. Choose 10% to preserve power and speed, 20% when the block needs volume.
What is velocity-based training?
It ends a set when bar speed falls by a set percentage from the first repetition, rather than at a fixed rep count or at failure. Because reps adjust automatically to how you feel that day, effort stays uniform from session to session.
Should I take every set to failure?
In this study, stopping later raised blood lactate more (29% versus 11%) but left post-exercise peak power and velocity lower rather than higher. It is useful in a volume phase, but finishing every set that way erodes the output available in the next session.
Does doubling the reps raise blood pressure more?
Not in this study. Systolic and diastolic blood pressure and heart rate showed no significant difference between the two protocols, despite twice the reps and nearly three times the lactate rise.
Source: PubMed