How velocity-based training is used in strength and conditioning
What bar velocity tells a coach, how GymAware measures it, how load-velocity profiles and velocity loss are used, and where the method has limits.
Velocity-based training, often shortened to VBT, uses the speed of the bar during a lift to help choose the load and decide when a set should end. The coach measures how fast you move a weight, and that number becomes part of the program.
This guide explains what bar velocity is, how it is measured, the two main ways coaches use it, how it appears in sessions at Onyx and what it cannot tell you.
What bar velocity is
Bar velocity is how fast the bar moves during the lifting phase of a repetition, reported in meters per second and usually averaged over the upward part of the lift. Heavier loads move more slowly. When you lift with full intent, the speed of a rep reflects how heavy the load is for you on that day: a load you can lift only once moves slowly, and a light load moves fast.
This relationship is the basis of the method. In a study of 120 strength-trained men in the bench press, the average speed of the upward phase was very closely related to the load expressed as a percentage of each lifter's one-repetition maximum, the heaviest weight they could lift once. The speed at each percentage stayed stable after six weeks of training, even though their maximum went up (González-Badillo and Sánchez-Medina, 2010).
How GymAware measures it
The lab uses GymAware, a linear position transducer. A small unit sits on the floor next to the lifter, and a thin tether runs from it to the bar. As the bar rises and falls, the tether pulls out of the unit and winds back in. The unit records the distance and the time, corrects for the angle of the tether, and calculates velocity and power for every rep in real time, so the coach can read the numbers before the next set.
The load-velocity profile
A load-velocity profile is a short test in which you lift several loads, from light to heavy, with full intent, and the speed of each one is recorded. Plotted together, the loads and speeds form a close to straight line that is specific to you and to that exercise. The coach can use it to estimate your maximum without a one-rep max test and to choose a load that should move at a target speed, for example a lighter load moved fast on a power day and a heavier, slower load on a strength day.
Readiness changes from day to day, so the same load can move faster or slower than usual. When your warm-up sets are clearly slower than normal, the coach can lower the working load for the day, and when they are faster, the coach can raise it.
Velocity loss and fatigue
As a set goes on and fatigue builds, each rep slows down. The drop from the fastest rep in the set is called velocity loss. A coach can set a threshold, for example ending the set once a rep is a chosen percentage slower than the first, so each set stops at a planned level of fatigue. Low thresholds keep the reps fast and the fatigue small, which suits power work. Higher thresholds allow more fatigue in each set.
Seeing the speed of each rep also gives the lifter immediate feedback on effort. A review by Weakley and colleagues (2021) describes how load-velocity profiles, velocity loss thresholds and velocity feedback are used in practice.
How Onyx uses it
In the Onyx Performance classes, the Power days on Tuesday and Friday open with jumps, medicine ball throws or sprints, and the main work is Olympic lift variations or lifts where the coach reads bar speed during the set and sets the load from it. In Onyx Protocol and Onyx Private, the coach reads bar speed in the strength block when your program uses it. The group classes page shows the weekly rotation, and the performance testing page lists the tests that sit alongside the training.
Its limits
Velocity only reflects effort when every rep is lifted with full intent, so a lifter who holds back makes the numbers meaningless. A profile belongs to one exercise and one device, and a change of device can shift the numbers. Technique matters too: a shorter range of motion or a change in bar path changes the speed. An estimated maximum is an estimate, and it gets less precise the further the heaviest tested load is from your true maximum. The coach's eye on the lift stays part of every decision.
Sources
- González-Badillo JJ, Sánchez-Medina L. Movement velocity as a measure of loading intensity in resistance training. Int J Sports Med. 2010;31(5):347-352. doi.org/10.1055/s-0030-1248333
- Weakley J, Mann B, Banyard H, McLaren S, Scott T, Garcia-Ramos A. Velocity-based training: from theory to application. Strength Cond J. 2021;43(2):31-49. doi.org/10.1519/SSC.0000000000000560
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