Workload Management: Going Beyond Acute:Chronic Workload

      Workload Management: Going Beyond Acute:Chronic Workload

      Many experiments end up as "failed" projects.  Many don't answer the initial question you may have set out to answer and sometimes they provide results contrary to preconceived notions.  On occasion, you'll stumble upon something significant by accident! This summer, we (Ryan Aruanno, Cam Earles & myself) stumbled upon one of those!

      Now, take this with a grain of salt because it didn't actually lead to anything......yet.  It lead to very interesting data that has turned into more questions and more discussions about what we saw.  Let's backtrack a bit and talk about the idea of workload management. We know that pitch counts aren't the greatest indicator, but they do provide some sense of accountability.  In recent years, discussions about Acute:Chronic Workloads have gained in popularity to offer a much better approach to managing workloads.  I don't want to dive into the ins and outs of Acute:Chronic Ratios (ACR), but here's a great link for anyone who wants to learn more on that topic. The only thing I want to point out about ACR, is that studies show that once that number gets above 1.3, the likelihood of injury goes up significantly. 

     This past summer, we implemented a bunch of things to collect data on in hopes of finding significant correlations.  A bunch of these involved a Wii Board.  One of which was to record shoulder force production. We measured Lying Y's & T's and Standing ER's (we had 1 more that we ended up taking out).  The initial thought was that measuring shoulder forces could give insight into velocity.  That was somewhat present but that's not the topic of this blog.  What it did, was lead to the thought that maybe there would be correlations with individuals producing more shoulder force and gaining velocity.  Results weren't quite as good with that, but it led us to an interesting though: "Could it possibly provide insight into recovery?"

      Now let's finally discuss the actual experiment! Using those 3 tests (Lying Y's, T's & Standing ER's), we measured dominant and non-dominant arms Pre & Post Throwing on most training days inside the facility.  Each athlete performed isometric holds while pushing into the Wii Boards as hard as possible for 2-3 seconds each.  2 reps were performed for each test and the average was recorded. For Recovery purposes, we didn't pay attention to the total numbers for each, but rather, we looked at the difference between dominant and non-dominant arm for each test.  Meaning that if an individual recorded a higher number with his dominant side than his non-dominant side, the number for that particular test would read as a positive number.  If the dominant was lower than the non-dominant, the number would read as a negative number.  

      As it worked out, there was 1 pitcher that we had using Motus Throw to monitor arm speed on a daily basis, so we decided to record ACR and Chronic Workload every day for him alongside of his Shoulder Force data!  Keep in mind the 1.3 number I mentioned previously because it's about to be a big part of this discussion.  Using this particular individual's data, we were able to get some very insightful information!  Below is a chart with his data.  *Note: this particular individual threw on days he didn't come to the facility also. He did use Motus Throw for all of his throwing, even away from the facility*  

ACR	Chronic WL	Date	Time After Pitching	ER Difference	Front Y Difference	Front T Difference
0.88	3.9	25-Jun	Pre Throw	2	0.7	0.85
1.35	4.6	25-Jun	Post Throw	-0.65	0.3	1.85
1.12	4.2	27-Jun	Pre Throw	1.85	0.8	-0.1
1.3	4.5	27-Jun	Post Throw	0.15	-1.45	0.3
0.58	4.6	9-Jul	Pre Throw	0.7	0.85	-0.25
0.93	5.1	9-Jul	Post Throw	1.8	0.7	1.6
		11-Jul	Pre Throw	-0.5	-0.65	0.95
0.86	7.7	11-Jul	Post Throw		0.3	0
0.91	4.6	16-Jul	Pre Throw	2.15	0.75	0.65
1.14	5	16-Jul	Post Throw	1.35	0.55	0.75
1.08	5	18-Jul	Pre Throw	0.5	1.6	1.35
1.28	5.4	18-Jul	Post Throw	-1.25	-2.3	-1.95
1.42	5.1	19-Jul	Pre Throw	1.5	-0.8	2.8
1.48	5.2	19-Jul	Post Throw	-0.1	-2.7	-0.3
0.71	5.4	6-Aug	Pre Throw	0.6	-0.5	2.7
		6-Aug	Post Throw	-1.45	0.1	2.7
0.93	5.9	8-Aug	Pre Throw	-1	-1.25	2.35
1.06	6.2	8-Aug	Post Throw	0.55	-2.2	-0.75
1.1	6.2	9-Aug	Pre Throw	-1.9	-3.4	-1.75
1.16	6.5	9-Aug	Post Throw	-0.5	-4.05	-0.7
		22-Aug	Post Throw	-1	-3.8	-2.9

       

      Remember that 1.3 ACR number??? Take a look at ACR on July 19th on the chart above.  That's the first time this athlete gets to a 1.4.  If you go back before this date, you'll notice that there are some negative numbers, but they are always post-throwing with one exception.  He came in on July 19th with an ACR of 1.42 and a negative Front Y score (which is the data point we paid extra attention to for this individual).  So at this point, it appears that ACR is a good indicator of fatigue!  But now let's go beyond that......

      Let's look at what happens AFTER July 19th.  For starters, there's a long period of time before we record data again.  That's because this athlete and myself went on vacation at different times during this period.  But let's pick back up with August 6th and note that this athlete took 1 week off from throwing while he was on vacation. Other than that, he was playing catch while using Motus Throw.  On August 6th, which is 2 1/2 weeks after his ACR went to 1.4, he still had a pre-throw Y Score of -0.5.  That's not a big difference, but it's still negative, nonetheless. Keep in mind, to this point, the Y Test has been the only test that's shown a negative Pre-Throw score so far.  

      Since ACR was in a good range now and the fact this athlete was trying to make a college roster for the first time, we wanted to return to a normal throwing routine.  However, as you should be able to clearly see, his Shoulder Force numbers were rapidly going the wrong direction.  We tried to pick and choose when he pushed since he was trying to make a team, but it wasn't an easy task seeing those numbers not return to a normal level.  This athlete ended up hurting his arm several weeks after getting back to college.  

      What does all of this mean and did we miss anything?  For starters, even though we were following ACR guidelines, I believe if we look back at Post Throwing on July 18th, there was something insightful that was reason for concern.  Although ACR was 1.28 Post-Throwing, the Shoulder Force Numbers were significantly down. While it was normal for this individual's Post-Throw Numbers to be slightly down, these were very significant.  The next day he didn't throw much at all and again, a significant drop.  What probably should have happened at this point was a period of low intensity throwing to give the arm a chance to recover.  At the time when Shoulder Forces were constantly low, his velocity readings during bullpens were constantly increasing.  So even though ACR was back in a normal range and velocity was increasing, the Shoulder Force Tests were providing data to suggest fatigue. 

      Maybe it takes a significant amount of time to recover once going above that 1.3 threshold. Maybe building chronic workload could've helped create more resiliency once high intensity throwing began.  Maybe high intensity throwing requires additional testing, such as what we did here, to get a full scope of fatigue.  While Motus does a great job of measuring ACR in terms of workload on the elbow, maybe tests like this provide insight into not only the arm, but the Central Nervous System.  What if a pitcher isn't well rested?  What if a pitcher is taxed from a hard lift the day before?  I'm not sure if anything is definitive, but I do know that this experiment provided insight to suggest that ACR matters!  To start easily tracking ACR, Motus provides a great, affordable product!