Using the Reactive Strength Index for Training Load Management
The first thing that we have to understand is if there is a technical model that aligns with the development of reactive strength. If there’s not, then the data still has value but it has inherent limits on it. These limits are based on the specifics of the test parameters: verbal instructions, reliability around protocol and test timing/frequency, box height, etc. The technical model structure will allow us to reflect on how well our model holds up to the stress of our environment.
In the technical model’s absence, we need to make two decisions about how we interpret the results. First, we need to accept that reactive strength as it is acquired during performance of a standard drop jump from 30cm/12ish inches is going to function solely as a monitoring tool. Second, we need to maintain consistency in the test’s timing. These two decisions allow us to clean up the interpretation of results a lot. But, these decisions also set a ceiling on the expression of reactive strength itself because a 30cm drop is pedestrian for well-trained athletes.
I would suggest exposing these athletes to incremental load drop jump testing, via a +/- change in box height, at specific time points. That way the testing can adapt to the athlete as the athlete adapts to the training. I am also going to bring up that a countermovement jump also has a high degree of relevance to reactive strength, as do lesser box heights. There is something essential to the ability to be able to do more, with less.
This thinking also lines up well with the performance of the 10-5 RSI test. Unlike the drop jump, we can perform the 10-5 on Day 1 in many environments and gather some quality data. The drop jump test may need more time and confidence from the support team before being instituted reliably. Even then, the familiarization processes around the drop jump would require up to 12-weeks.
So what else can you do as a coach when an athlete demonstrates a drop in reactive strength? I would like for coaches to consider how accessible specific training characteristics (eccentric training, plyometric training, max strength work, etc) are across their program. We are all attempting to optimize loading in any given microcycle based on previous training. Why would we ever plan this any other way? But much of these loads require tremendous stress to drive the adaptation processes. There is an increased cost to even subtle increases in load.
I’ve used the example of being a basketball player and playing one-on-one every day against a player of increasing difficulty. Sure, working your way up to playing Lebron James is going to push you and challenge you, but there will be a limit to the growth and learning you experience. That limit is based on how well you can represent quality in each basketball effort.
Especially when King James is smashing you every single day.
Alternatively, you can find a player that you are either a little better than, perfectly matched against, or someone a little better than you. Playing against these opponents will allow you to express these skills differently but in complementary ways.
This is what loading and “surfing the force-velocity curve” should be all about.
If we add readiness into the equation, done in part by measuring reactive strength, then we can best align these loading parameters to match our current capabilities.
The Strength and Conditioning field needs to be better at anticipating these conditions in programming while demonstrating adaptability to who is standing in front of us on any given day. The development of greater performance may be limited in any given day’s training. But, we can still express competency at loads that will not completely derail our training plan.
For instance, is a 75% load done for 5 sets of 3 that much different from an 85% load done for 6 sets of 2?
This will always depend on additional factors but much of the scientific literature suggests that they are not that different. Provided the athlete is well-trained then this will shift how force and velocity are expressed in the movement.
Beyond that, the practicality of the situation suggests that if we are adjusting due to decreased readiness, the 85% load done for 6 sets of 2 would never have happened. The better question we should be asking is: is a change as good as a rest?