Velocity Loss Cutoff - The Most Actionable VBT Metric For Coaches and Athletes
By Chris Chapman
October 25, 2017
With a seemingly endless amount of gym-tech available, combined with the widespread adoption of velocity-based training (VBT), it’s easy to get lost in the chaos of information available ‘on-the-line’. However, when it comes to the daily practical application of objective measurement, simple and actionable reign supreme. We want to bring back the simplicity of VBT, which is why we are introducing the ‘Velocity Loss Cutoff’ feature: to help drive easy implementation of autoregulation.
Absolute velocity zones were initially created to drive the training of specific strength qualities. While I first saw this automatically implemented in the Myotest device a decade ago with load-velocity profiling, I give Bryan Mann credit for bringing mainstream attention to this concept. He got everyone thinking differently about velocity zones by anchoring them to Bosco’s strength continuum, strengthening the validity of this relationship. If they didn’t already, most velocity measurement tools added in the ability to select these predefined zones or prescribe a custom range of absolute velocities to guide the lifter during training.
As more researchers started exploring VBT they soon realized each exercise has its own range, shifting the goalposts of these zones (Table 1 and 2). This is even further complicated by the individual variability in response. For example, these tables also show stronger and more skilled athletes can grind out slower speeds for minimum velocity threshold (MVT) or velocity at 1-reptition maximum, which is an end-point for these zones and an anchor-point for profiling.
The potential mechanisms for these observations are plenty, and beyond the scope of this article. Regardless, it does complicate the programming and application of absolute velocity zones in the daily training environment. Subsequent blanket usage for a single program or group of lifters is not easily implemented.
While not completely overlapping in purpose, using velocity loss instead of velocity zones solves the problem. The key difference is that velocity loss provides relative, rather than absolute values. It is the percent difference in velocity between the current repetition versus the first- or best-repetition. Therefore, regardless of the exercise, regardless of the individual, a single percentage threshold can be set for a given program or group of athletes. This makes implementation much easier for the coach to prescribe AND for the athlete to follow.
With a baked-in Velocity Loss Cutoff feature, the PUSH iOS app is designed to make autoregulation simpler. The user sets a percentage of velocity loss they want the lifter to stop at, and the iOS app will inform the user in real-time when this threshold has been hit. Both audio (i.e., bell 'ding' means lift is good, ‘buzzer’ indicates lift is below cutoff) and visual (velocity value and bar turn red and notification appears) indicators are given to the user when this occurs. Metrics will still be measured for every lift after that point and the user can choose to keep lifting if desired or instructed to continue. For the athlete, it couldn't be more simple: lift with the prescribed intent until notified when to stop.
Using a velocity loss cutoff has been discussed in-depth previously. VBT pioneer Dan Baker explains why using it is so important in the video below. Sport scientist Carlos Balsalobre-Fernandez, who has built his own iOS apps for tracking various gym, running and jumping metrics, has previously written on our blog about this topic, as it is not new and has been supported in the literature for some time now. Sanchez-Medina and Gonzalez-Badillo first published a paper on this concept in 2011, which clearly shows that the percentage of velocity loss observed correlates highly with markers of both mechanical and metabolic fatigue. It follows that a lifter who terminates a set at a given amount of velocity loss can avoid accumulating excess fatigue. This is powerful as it brings objectivity to an area that has typically been measured subjectively in the gym with ratings of perceived exertion.
Coming from the same research group in Spain, two further studies led by Pareja-Blanco utilized this principle in short-term training program models, more similar to a single block or mesocycle that a strength coach might prescribe. The first study compared 8 weeks of squatting between one group that was assigned a 20% velocity loss cutoff (VL20) and the other a 40% velocity loss cutoff (VL40). The relative loading was matched for each session across groups, with the only difference being the volume or number of repetitions performed, as sets were terminated when the velocity of the squat dropped below the cutoff value. This equated to approximately half the number of repetitions in each session. Strength and jump performance tests were completed pre- and post-training, in addition to biopsies to observe the effects at the muscle fiber level. VL20 resulted in equal strength gains and greater jump performance than VL40, while performing 40% fewer squat repetitions over the 8 weeks. On the other hand, VL40 had greater muscle hypertrophy combined with a reduction in fast twitch fibers. For a coach, by utilizing a more strict (smaller) cutoff for set termination, lifters can acquire equivalent or greater performance gains while preserving explosive muscle qualities, all while accumulating less volume and fatigue.
This was reinforced in the second study, which applied this same velocity loss principle with professional soccer players over a 6-week block of training that used both upper and lower body exercises. The only difference between the training groups compared to the last study was a velocity loss cutoff of 15% (VL15) versus 30% (VL30) between the two groups. Once again, the lower percentage cutoff VL15 group had equivalent or greater gains across a battery of performance tests while enduring less volume of training and therefore accumulating less fatigue. As the authors' state in their discussion, setting a percent velocity loss threshold during resistance training is a way to avoid performing unnecessarily slow and fatiguing repetitions that may not contribute to a desired training effect.
Translated into the real world, these results are a win for all parties involved. It is a win for the athlete as they are performing at an equivalent or better physical level, a win for the coach as the athlete will have more in the tank to focus on technical and tactical training, and a win for the S&C coach as they will have induced less fatigue in the athlete heading into an important sport training block or competition.
Regardless of your tool of choice, using velocity loss is one of the easiest and most valuable applications of the VBT methodology to implement in the daily training environment. Whether it's for autoregulation, targeted adaptations, or in-season training/peaking, this easy-to-use concept can be applied to a wide range of desired outcomes.
If you have a PUSH band, taking advantage of our new Velocity Loss Cutoff feature is easy. It’s been designed to be as simple as possible for both the coach to implement and athlete to use. Give it a spin and let us know what you think!
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Baker, D. (2016) PUSH // Train With Purpose - VBT Guide. [ONLINE] Available at: https://www.trainwithpush.com/3-part-vbt-guide/. [Accessed 15 Oct 2017].
Walker, O. (2017) Velocity Based Training [ONLINE] Available at: https://www.scienceforsport.com/velocity-based-training/. [Accessed 15 Oct 2017].
Mann, J.B. (2015) Velocity Based Training. [ONLINE] Available at: http://www.ncaa.org/health-and-safety/sport-science-institute/velocity-based-training. [Accessed 15 Oct 2017].
Sánchez-Medina, L., González-Badillo, J.J. (2011) Velocity loss as an indicator of neuromuscular fatigue during resistance training. Med Sci Sports Exerc. 43:1725-1734.
Pareja-Blanco, F., Rodriguez-Rosell, D., Sánchez-Medina, L., Sanchis-Moysi, J., Dorado, C Mora-Custodio, R., Yanez-Garcia, J.M., Morales-Alamo, D., Perez-Suarez, I., Calbet, J.A.L., González-Badillo J.J. (2016) Effects of velocity loss during resistance training on athletic performance, strength gains and muscle adaptations. Scand J Med Sci Sports. 27(7): 724-735.
Pareja-Blanco, F., Sánchez-Medina, L., Suárez-Arrones, L., and González-Badillo J.J. (2016) Effects of velocity loss during resistance training on performance in professional soccer players. Int J Sports Physiol Perform. 12(4): 512-519.
About the Author
Christopher Chapman - Director of Sport Science at PUSH
Prior to joining PUSH, Chris was the Lead Strength & Conditioning Coach at the Canadian Sport Institute Ontario where he spent 8 years in the trenches helping Olympic and National teams, as well as athletes, to podium performances. While being a strength and conditioning coach by trade, Chris is a multi-dimensional practitioner and sport scientist, academically trained as a biomechanist, athletic therapist, kinanthropometrist and physiologist.
Follow Chris on Twitter @ChappyStrength