Ex. of 120% velocity difference, are you missing the benefit of early range of motion VBT feedback?

Preview note: the video clip is a use-case example shared by an elite level team sport coach, using the MoveFactorX product for VBT feedback. The clip is a close-up of the user interface of the MoveFactorX (sport) mobile application (iOS), showing the instant feedback after each repetition of a high pull. The ultra-portable MoveFactorX module (less than 30 grams in weight) is attached to the barbell and secured with a neoprene sleeve barbell wrap.
Reps 1-2 were performed from a high pull starting hang position and included a countermovement (eccentric/concentric phases). Reps 3-4 started from a static position (no countermove, concentric only).
The question, what are the differences of the barbell performance outputs using two different movement techniques for the high pull?
The point being made with this example is the much greater early range of motion expression of Velocity and Force output (rate of force development/RFD likeness) during Reps 3-4 (static start) vs using the countermove technique of Reps 1-2.
You can see the Peak Velocity is very close for all 4 repetitions, yet the early expression of Velocity (displayed with the POP-100V and POP-200V metrics) is much greater when the athlete started from the static position (again, Rep 3-4).
Please carefully review the results over the 4 repetitions. This objective data may suggest if only the traditional metric of Peak Velocity (full range of motion) was used to evaluate the athlete's performance, the potentially more relevant metrics (i.e. POP-100V & POP-200V) would be missed. The relevance is based on the assumption that the VBT sport tech feedback is being applied to monitor performance metrics that transfer to the sporting task.
First off, let's please explain what the POP metrics represent:
- POP-100V is the Velocity reached at the 100 millisecond point (0.1 sec) of the concentric phase (it is a moment in time).
- POP-200V is based on the same premise at the 200 millisecond point (0.2 sec).
- Peak Velocity is a variable point in time where the highest velocity is reached (end of the barbell acceleration), and typically achieved near the end of the range of motion for a ballistic oriented lift.
(all velocity measured are displayed in meters per second, M/S)
Within mainstream VBT sport tech use (velocity-based training) of a ballistic oriented lift, Peak Velocity is the most commonly adopted metric as it has been available in a practical manner for over 14 years. Within this high pull set the Peak Velocity results were 1.89, 1.8, 1.74, 1.86 m/s. Considering inherent variability with each athlete's movement on a rep-to-rep basis, these results would indicate nice consistency and a "valid" VBT data set.
Although, back to the question poised a bit earlier, Peak Velocity as a stand alone metric does not illustrate the potentially more meaningful VBT data, and certainly does not help delineate between the countermove vs static starting position (the entire premise of showing this video clip & explanation example). Recall, Peak Velocity is the max velocity near the end of the full range of motion.
What we understand related to most sporting tasks, force developed in the early phase of the range of motion is typically the "difference maker" when it comes to on-field performance, the sporting task. Rarely does an athlete have the opportunity (or time) to express a full range of motion, this is a key point when considering is your sport performance training, or sport tech feedback, offering the granular information that is more relevant to the goals of the performance training?
If most of the action of the sporting task is occurring within tight time windows (i.e. 75 - 150 milliseconds), should you be assessing those same time windows when monitoring the sport performance training aspect? We think so, and have made it a point to move the needle forward and provide the forward thinking metrics to modernize your approach to VBT sport tech feedback.
Back to Reps 1-2 vs Reps 3-4. We already stated how the Peak Velocity is very consistent across the set, offers value but probably not the real story.
Now, let's look at the POP results:
- POP-100V 0.35, 0.45, 0.88, 0.88
- POP-200V 0.78, 1.04, 1.68, 1.69
Reps 3-4 illustrate a significant increase of early range of motion RFD as expressed with the POP velocity measures. The earliest window (POP-100V), and possibly the most important related to transfer to the sporting task, shows a 120% increase with Reps 3-4 compared to Reps 1-2.
Our movement performance platform offers velocity-based training feedback as one of its core features. We provide data, not programming decisions (that is the job of the coach). We strive to make the meaningful metrics available and practical to you; the metrics that transfer to the sporting task and assist with improved programming decisions.
(special thank you to Coach Junya Funato for sharing this high pull set content)