Data for the Data Averse

This article was written by Brett Jones, Chief SFG instructor at StrongFirst.

“Not everything that matters can be measured, and not everything that is measured matters.” Elliot Eisner

We live in the age of “Big Data.” Information floods our lives on an ongoing basis. And in the training world that means wearables and trackers giving us the ability to collect our own “big data.” Side note…the largest fitness show is now the CES (consumer electronics show) where an entire floor is dedicated to fitness wearables and according to Forbes 125.5 million devices were estimated to be shipped in 2017. Big deal this big data.

Now I will come out and say that I am a bit data averse and that over the years beyond a heart rate monitor I have not successful integrated “big data” into my training. But I may have found something that is changing my mind.

What am I tracking that is changing my mind?

Power and Velocity.

Velocity based training has become a trend in strength and conditioning. And the blog at Train With PUSH is an excellent resource.

A quick detour…

In physics there is something known as Observer Effect, basically meaning that the act of observing something changes it. As noted in this article on Science Daily research shows that:

“When a quantum "observer" is watching Quantum mechanics states that [sic] particles can also behave as waves. This can be true for electrons at the submicron level, i.e., at distances measuring less than one micron, or one thousandth of a millimeter. When behaving as waves, they can simultaneously pass through several openings in a barrier and then meet again at the other side of the barrier. This "meeting" is known as interference.

Strange as it may sound, interference can only occur when no one is watching. Once an observer begins to watch the particles going through the openings, the picture changes dramatically: if a particle can be seen going through one opening, then it's clear it didn't go through another. In other words, when under observation, electrons are being "forced" to behave like particles and not like waves. Thus, the mere act of observation affects the experimental findings.”

(how cool is that?)

Essentially the act of observing something can influence the thing being observed and when I started “observing” my swings with the PUSH Band it absolutely influenced what I was doing.

I began to max out (swing at a volume setting of 11 – Spinal Tap reference) my swings and it had a big impact on my form. Due to the amount of power produced I was not holding my finish position but was unhinging and sitting back slightly to counterbalance the kettlebell (I was even pulled off the ground on a couple of reps). This was subconscious. I immediately had the volume knob way up to max out my power since it was being measured and I did not realize the impact it had on my form until looking at video. And it highlighted a difference in power between my right and left arm swings. (Left being more powerful even though it is my non-dominate arm)

Just be aware that the Observer Effect applies to swings as well…

Moving on

Why measure power and velocity?

It assists us in knowing when to stop a set.

Why is it important to know when to stop a set?

Understanding the cost of training and how to maximize the return on investment of training.

In Strong Endurance Pavel has highlighted understanding the cost associated with the different energy systems. Prioritizing high power output with adequate rest periods so your body builds capacity in energy production and efficiency in dealing with the byproducts of that energy production. Craig Marker has a couple of articles that dive a bit deeper into these concepts and Pavel has some great information in this article: Simple and Sinister Progression Tactic.

So, the question for me has become: “What is the cost?”

If I am programming for myself or my students, I ask myself that question. Understanding the cost associated with something is critical to programming and recovery. And the best recovery strategy is proper programming!

What does this have to do with Velocity and Power measurement/tracking?

In Dan Baker’s excellent article series available on PUSH website he details research done using velocity loss as the metric for training.

“…the researchers (Gonzales-Badillo et al. 2016) looked at the relationship between velocity, effort, and fatigue, and the consequent training adaptations and time course of recovery from fatiguing and less-fatiguing workouts. The study investigated the effects of performing 3 x 4 @ 80% 1RM (with about a 20% velocity decline) versus 3 x 8 @ 80% 1RM (with about a 40% velocity decline) for squats. The results were that jumping capabilities of the athletes performing the 3 x 4 workout were recovered within 6 to 24 hours. The results for the 3 x 8 group were not fully recovered at the 48-hour mark.”

This research syncs well with Plan Strong methodology and enhanced recovery. What is interesting is the drop in velocity which Pallares et al put into action in their 2016 research.

See below:

“…the researchers (Pallares et al. 2016) trained two groups of athletes for 8-weeks using a periodized training approach ranging from 70 to 85% 1RM. What distinguished between the groups was that one groups ceased their squats sets at a 40% velocity decline within the set and the other group trained to a 20% velocity decline within the set, irrespective of what % 1RM or how many reps were performed. Across the 8-wks, the 20% decline group performed only 60% of the workload/reps of the 40% decline group. The results were the same for increases in 1RM squat strength, but the 20% decline group had better jumping improvements while the 40% decline group had better muscle size gains. However, these greater gains in muscle size also came with a catch ~ there was a decrease in the percentage of explosive MHC 2 fibers! This is not an outcome that power athletes would desire, as these are the more explosive muscle fibers.”

The big takeaway

Higher reps and large decreases in velocity within a set result in large increases in lactate and ammonia, make it more difficult to recover from the resistance training session.

Please note the 6 to 24-hour recovery vs. 48+ hour recovery in the one study and the benefits achieved at only 60% of the workload in the other (without sacrificing explosive fibers!).

This is Strong Endurance!

Now you may be thinking that you “know” when power drops off etc… but I can assure you that based on my experience with the PUSH Band and my years and many reps of swings that you are not.

What does it look like?

Sample training sessions

Feb. 14, 2018 – One-arm Swings w/ 40 kg
10 every 2 min x 6

Set 1: - L x 10 - peak power - 1846
Set 2: - R x 10 - peak power - 1836
Set 3: - L x 10 - peak power - 1841
Set 4: - R x 10 - peak power - 1846
Set 5: - L x 10 - peak power - 1821
Set 6: - R x 10 - peak power - 1872

This was a short practice session with ample rest where loss of velocity was not likely but had it happened or if I was coming into my training without full recovery etc…I would have been able to see it and quantify it right away. Sets were performed at about a volume setting (effort) of 6-7 and you can see good power.

So what does a session look like where I push to the point of losing power?

March 1, 2018
Two-arm swing 40 kg x 10 x 10 sets
30 seconds rest between sets

Set 1: - peak power - 2204
Set 2: - peak power - 2159
Set 3: - peak power - 2104
Set 4: - peak power - 1928
Set 5: - peak power - 2188
Set 6: - peak power - 1946
Set 7: - peak power - 1877
Set 8: - peak power - 1905
Set 9: - peak power - 1782
Set 10: - peak power – 1770

Please note the drop off in power and velocity in the last two sets. I felt "beat up" by the session - which validates the idea of stopping when 10%-20% or so drop off and not recovering well if you do not stop the session at that point. I should have stopped after set 8 and possibly after set 7.


You do need to wear the band on the arm performing the exercise. This means switching arms each set on most protocols. With enough of a rest period this isn’t difficult but with short rest it can be an issue or you would track only one arm etc…But having used the PUSH Band for some time now I find the protocols easy to input and the device easy to use (even switching hands in a 20 second rest period).


Changing my mind on big data might not be there fully but I think I can embrace this technology and have benefited from tracking velocity and power. Identifying left to right asymmetries in power or velocity, managing drop-offs in power and velocity can be huge to understanding the cost of training. And the benefits of managing that cost is what put StrongFirst and Strong Endurance at the forefront of strength and conditioning information. The ability to track variables like velocity and power just put reinforcing data and metrics in place.

About the Author


Brett Jones is StrongFirst’s Chief SFG Instructor. He is also a Certified Athletic Trainer and Strength and Conditioning Specialist based in Pittsburgh, PA. Mr. Jones holds a Bachelor of Science in Sports Medicine from High Point University, a Master of Science in Rehabilitative Sciences from Clarion University of Pennsylvania, and is a Certified Strength & Conditioning Specialist (CSCS) from the National Strength and Conditioning Association (NSCA).

With over twenty years of experience, Brett has been sought out to consult with professional teams and athletes, as well as present throughout the United States and internationally.

As an athletic trainer who has transitioned into the fitness industry, Brett has taught kettlebell techniques and principles since 2003. He has taught for Functional Movement Systems (FMS) since 2006, and has created multiple DVDs and manuals with world-renowned physical therapist Gray Cook, including the widely-praised “Secrets of…” series.

Brett continues to evolve his approach to training and teaching, and is passionate about improving the quality of education for the fitness industry. He is available for consultations and distance coaching by e-mailing him at

Follow him on Twitter at @BrettEJones.