Pitch Counts and Inning Limits Are Not Doing The Job

Basic injury models always point to mechanics, innings, past injuries, frequency, time of year, chronic workload models and ratios, isolated strength and mobility, age, and so on. While these factors can certainly play a role, this thought process avoids what injury actually is and how it occurs in my opinion. A human is a complex nonlinear system with constantly shifting interactions between coordination strategies, physical capacity, and environmental constraints. An acute injury occurs when these interacting subsystems lose stability, risk doesn’t increase 10x when a certain variable or two crosses a random threshold. A dynamical systems approach treats injury as a systems level failure. Essentially, Injury emerges when the system can no longer adapt and distribute stress across multiple solutions and instead collapses into a narrow rigid pattern that breaks down under load. Basic linear models consistently miss both the timing and mechanism of breakdown although many isolated variables are accounted for. What gives?

One of the earliest indicators of a systems level failure is the loss of “good” variability. “Good” variability can be looked at as adaptability inside a stable movement solution while “bad” variability could be looked at as disorganized compensations of a degrading system in this case. A pitcher who averages 97 MPH on his fastball achieves consistent outcomes through variations in timing of certain segments within the parameters of his own system. This “good” variability can protect the system by properly allocating stress across multiple solutions and sequences. Issues can emerge from throwers that become rigid within a narrow solution and use a set of compensatory pathways to try and achieve the same output over and over. This can lead to stress falling upon solutions that are rigid in nature. Outputs can even remain stable all the way up until injury occurs in some cases which makes this a very difficult problem. I think of this as cruising 100 mph on an empty highway vs. driving 100 mph on a narrow street. A very watered-down analogy, but you get the idea.

Fatigue among a few other things will accelerate this narrowing of solutions. As muscular fatigue, sensory degradation, etc sets in, motor solutions narrow. The system uses stiff and rigid patterns that are easier to execute but harder more repetitive on tissues and joints. The system is essentially trying to protect. Athletes with more exposure to viable movement solutions withstand this degradation more effectively than athletes that complete most of their skill work with a narrow model in my opinion. More variability in practice can build healthier and more robust pitchers in general.

The system often reveals some sort of instability or deviation before performance metrics collapse and acute injury occurs. I believe a closer eye on year-round movement and biomechanical data, pulse data, and athlete feedback can be really beneficial here. Looking to system coordination deviations, shifts in sequencing and segmental velocities, command fluctuations, or mild increases in perceived effort can point to a system level failure before it happens. Degrading command, large shifts in sequencing, or an athlete giving feedback that he feels he is trying 10% harder for the same velocity brings up a red flag that should be further addressed before that athlete crosses a threshold where a minor issue causes a major injury event.

Basic measures for most injury prevention protocol like innings, pitch count, age, previous injury falls severely short in my opinion due to variability within these metrics and how adaptable humans are as species. A pitcher with 200 innings on the season (1.02 WHIP) could deal with less physiological stress over the course of a season than a pitcher with a 1.46 WHIP over 150 innings. On a smaller scale throwing 85 pitches over 8 innings is probably going to be a lot less stressful than 65 pitches over 3 innings. Pitchers coming out of spring training throwing at higher velocities at age 34 than age 27 also proves that humans can adapt to many different stressors even at advanced ages. Frequency and volume can also be trained to handle most any reasonable workload. Training needs to better prepare athletes to deal with what the season is going to throw at them. Not a simplistic view of what one thinks the season is going to look like. More general capacity, exposure to variability and intent, and better physical preparation is a good place to start. Hammer the basics. Exceed the demands in a controlled environment.