In college strength & conditioning, it can be challenging at times to come up with objective measurables that we can use to track the progress of our student-athletes over the course of a semester or season. I have seen and spoke with other coaches about using movement screens, rep max calculators, calisthenic rep-efforts, conditioning tests, and many other methods. Often times, sport coaches are part of this discussion as well. They will have decided on certain benchmarks such as a timed mile, a Man U conditioning test, or other “sport-specific” tests to determine how fit a player is to be an asset to their team.
In individual sports such as track & field or swimming, an individual’s PR will often speak for itself. Especially when they hit that mark in a major competition or conference tournament. What about team sports? How can we provide objective evidence of a player’s improvement, or decline? One of the things I’ve been using over the past year and a half is the Power Output.
How do I determine a power output?
- Perform the test on the same day each week during regular training.
- Record each player’s body weight and the average of 3 vertical jumps.
- Use a simple equation, and let my excel spreadsheets do the rest.
The test goes as follows:
Generally, I will take the team on their first training day of each week and do simple weigh-ins once they come through the door. I weigh them with shoes on since they will be wearing them when they jump, and I want the formula to account for the total mass of the athlete while jumping.
Here is a study which evaluates multiple formulas accuracy for determining power outputs compared to force plate data. Encouraging from this paper is that these formulas actually undershoot power outputs, and listing Sayers’ work as most accurate in calculating the counter-movement jump which we employ for our data collection.
While not the exact same one used in the study, I stole the Sayer’s Power Equation from this article by Bryan Mann:
PAPw (Watts) = 60.7 x jump height(cm) + 45.3 x body mass(kg) – 2055
Following weigh-ins, we will do a quick general warm up and hit the jump mat. With basketball I can run them through in one shot as a team and it takes only a few minutes. This is usually more fun for them as well since they perform exceptionally when there is a larger peer audience.
When I’m dealing with a larger team like Soccer, I will usually include the jump mat as part of my circuit-style warm up exercises following our general warm up as a team. That way I can get them in smaller groups of 6 or 7, and still get through everything else in an efficient manner. Of course, this might compromise validity in a true scientific study but I have a set amount of time to work with, and this is how I do it.
What does the Power Output tell us about progress or regression?
I like the power output as an objective measurable for a lot of reasons.
- I have a great scale and a jump mat at my disposal. Both are quick and easy to use.
- It gives me an objective value for each player that is easily tracked over a semester.
Here is a small chart I’ve done to cover possible rationale for results, and how they may be interpreted. Green = Positive Adaptations, Yellow = Neutral adaptations that I recommend keeping an eye on as weeks progress. Red = Negative adaptations that may require investigation or possibly intervention.
Here is an example of a 23-week collection of data for one of my athletes. The spreadsheet has a drop down menu which is covered in red, where I can select any athlete I want to see the data for. Their statistics will appear in either the “uppers” columns if they have been with me all summer, or in the “fresh” column if they joined us in second session. In this case the athlete is a sophomore, and has been training for the entire duration.
And here below are three zoomed in shots from the above spreadsheet.
Before I go any further, here is how I set up my spreadsheets that I’ve used above. Before you bash the audio quality, I’m a strength coach first, a computer guy last.
All in all, I think this provides a great look into performance gains and implied improvements in body composition. The best part in this case is that these improvements are still occurring while we are in season. Again, the interesting part about the power output score is that we can see 3 different charts. The body weight chart suggests that the athlete is still above team average, the vertical jump chart suggests that the athlete is below team average, but the power output chart demonstrates the athlete is consistently putting out more wattage per kilogram of body weight than the team average, and not just by a little bit! Per my color-coded chart above, the middle box in the top row suggests this is an athlete who is consistently losing unnecessary weight.
So what is the value of a watt?
In our context, we are cultivating more data to determine just how important wattage is and what could be determined a significant gain. One of my freshman athletes has gained 13.8 pounds body weight and increased power output by 613w while adding 2.13″ to the vertical jump. This of course could easily be chalked up to “newbie gains” which is why I didn’t choose to profile that data set. In that context I can explain that she’s “made the jump” in comparable performance from one of our freshman back row volleyball players to one of our sophomore outside hitters. When we can personify the data to the athletes in this way, it becomes much more meaningful to them, and positive reinforcement runs its course. I am looking forward to finding trends with our soccer, track, volleyball, and basketball players to find out positional and sport-specific values.
So what’s the big deal with vertical jumps as a measurement?
A vertical jump can give us a lot of information about an athlete’s ability to generate power, and accelerate their body mass. As well as their ability to do this from week to week. The weekly component affords us additional pieces of information such as training status, insight toward their recovery capacity, and the effects of the training cycle that has been implemented. Furthermore, in-season, it can give us a snapshot of how well they are retaining the benefits of past training, or if they are being torn down by their competitive schedule.
Having said this, there are periods where a slight decline in power output can be a good thing. During periods of extended strength cycles, or leading into a “deload” period (a.k.a. school out of session) we can interpret a slight depression in performance as a signal of needing rest, and being sure that they will get it once they leave. Additionally, as you may choose to enter a power or conversion phase following the strength cycle, you will have objective data to determine the efficacy of those as well.
A vertical jump however, is much more than just a spectacle (or disappointment in some cases.) An athlete’s ability to accelerate their center of mass is an indication that they will be prepared to make greater, more relevant achievements in their sport. They are now better equipped to take a stronger first step, cover more ground in their first few strides, and contest headers, rebounds, passes, or line drives. Provided they have been properly educated in decelerating their mass in multiple planes, they are also prepared to become more agile.
The bottom line is that, when we can assign a measurement to how efficiently an athlete moves their own body mass, we’ve determined their capacity for better performance. Additional tests for determining agility or sport specific patterns would further validate these results in team sports.