Do you need mean propulsive velocity?

Velocity-based training (VBT) is a simple, reliable 1, 2, and accurate method of prescribing and monitoring training. However, one of the most important considerations and frequent questions is ‘What velocity variable should I use?’. The three most common variables in practice and research are mean velocity, mean propulsive velocity, and peak velocity. However, the variable that you choose can cause large differences in the values that you receive and how you monitor your athletes. Therefore, it is important to understand when to use each velocity variable and how they are calculated. Briefly, the calculation of each variable can be seen below:
Mean velocity is calculated as the value from the start of the concentric phase until the bar reaches the maximum height.
Mean propulsive velocity is calculated as the value from the start of the concentric phase until the acceleration of the bar is lower than gravity (-9.81 m·s-2).
Peak velocity is the maximum instantaneous velocity value reached during the concentric phase at a given load.

To know which variable to choose, it is important to know your goals for the training or testing session. Neuromuscular function can be assessed by measuring the velocity value achieved against a given load using traditional (e.g., bench press or squat) or ballistic (e.g., bench press throw or vertical jump) exercises. When testing with light/moderate loads (i.e., ≤70% 1RM), it is recommended that ballistic exercises are used (e.g., bench press throw rather than the traditional bench press variant). The reason for this is because it removes the braking portion of the concentric movement and provides a true reflection of an athlete’s ability. Therefore, when using relatively low loads, peak velocity is recommended as it does not measure the flight phase (unlike mean and propulsive velocity) and provides improved reliability (which is important for the consistent measurement of your athletes) 3. Furthermore, if using ballistic movements to measure performance, mean propulsive velocity could be even more problematic than mean velocity due to difficulties in detecting the exact moment take-off occurs. This issue may explain the counterintuitive findings reported in the scientific literature such as the power developed in a traditional exercise (e.g., bench press) being greater than its ballistic variant (e.g., bench press throw) 4. When assessing athletes with heavier loads (e.g., >80% 1RM), values provided between mean and mean propulsive velocity are practically identical, and all three velocity variables could be used 5.

 

(Image 1 – GymAware features a wide variety of different metrics)

When using velocity to estimate an athlete’s one repetition maximum and create a load-velocity profile, it is generally recommended that mean velocity is used. The reason for this is because the load-velocity profile has been shown to demonstrate greater reliability when calculated with mean velocity compared to mean propulsive velocity. Additionally, when compared to peak velocity, by using mean velocity load-velocity profiles have been shown to demonstrate greater linearity and the between-subject variability in the velocity attained during 1RM attempts (which is important for estimating maximal strength and knowing proximity to failure) is lower.

Given that peak velocity can ensure greater reliability at a range of sub-maximal loads, mean velocity provides the greatest linearity when developing load-velocity profiles and improved ability to estimate sub-maximal and maximal capacity, these two variables (mean and peak velocity) are provided with GymAware and Flex. These have been recommended throughout the scientific literature as the most accurate, reliable, and beneficial methods of monitoring performance 3, 5, 6, and avoid issues that are often introduced when using the mean propulsive phase of a movement (e.g., inclusion of the flight phase during ballistic exercises) 7.

References 

1. Weakley J, McLaren S, Ramirez-Lopez C, et al. Application of velocity loss thresholds during free-weight resistance training: Responses and reproducibility of perceptual, metabolic, and neuromuscular outcomes. Journal of Sports Sciences. 2020;38(5):477-485.
2. Pearson M, García-Ramos A, Morrison M, Ramirez-Lopez C, Dalton-Barron N, Weakley J. Velocity Loss Thresholds Reliably Control Kinetic and Kinematic Outputs during Free Weight Resistance Training. International Journal of Environmental Research and Public Health. 2020;17(18):6509.
3. García-Ramos A, Pestaña-Melero FL, Pérez-Castilla A, Rojas FJ, Gregory Haff G. Mean Velocity vs. Mean Propulsive Velocity vs. Peak Velocity: Which Variable Determines Bench Press Relative Load With Higher Reliability? The Journal of Strength & Conditioning Research. 2018;32(5)
4. Loturco I, Pereira LA, Abad CC, et al. Bar velocities capable of optimising the muscle power in strength-power exercises. J Sports Sci. Apr 2017;35(8):734-741. doi:10.1080/02640414.2016.1186813
5. Weakley J, Mann B, Banyard H, McLaren S, Scott T, Garcia-Ramos A. Velocity-Based Training: From Theory to Application. Strength & Conditioning Journal. 2020;Publish Ahead of Printdoi:10.1519/ssc.0000000000000560
6. García-Ramos A, Weakley J, Janicijevic D, Jukic I. Number of Repetitions Performed Before and After Reaching Velocity Loss Thresholds: First Repetition Versus Fastest Repetition—Mean Velocity Versus Peak Velocity. International Journal of Sports Physiology and Performance. 2021;1(aop):1-8.
7. Jaric S, Garcia Ramos A. Letter to the editor concerning the article “Bar velocities capable of optimising the muscle power in strength-power exercises” by Loturco, Pereira, Abad, Tabares, Moraes, Kobal, Kitamura & Nakamura (2017). Journal of Sports Sciences. 2018/05/03 2018;36(9):994-996. doi:10.1080/02640414.2017.1348015