Constraints-led approaches in baseball, trees decomposing, and accepting what is

📝 Weekly paper summary

Comparing Cueing and Constraints Interventions for Increasing Launch Angle in Baseball Batting (Gray, 2018)

Context

The instructions researchers or practitioners provide people before performing a task influence how they coordinate subsequent actions. The theoretical background underpinning the use of prescriptive, internal focus of attention instructions is that people adjust the parameters of a generalized motor program to perform discrete actions. Thus, an internal focus of attention cue can help facilitate the performance of an "optimal" technique. In contrast, an ecological dynamics approach to motor control proposes no optimal technique for goal-directed actions. Thus, researchers have proposed two main methods to promote the individual to find their own movement solution to achieve the desired outcome. One way is to use an external focus of attention that directs the focus to movements' effects and "allows the motor system to more naturally self-organize." The second way is to use a constraints-led approach (CLA) that deliberately manipulates task, environmental, or personal constraints during practice. Researchers and practitioners can use constraints to eliminate potential degrees of freedom, amplify errors, create opportunities for action, or facilitate variability and essential noise, so the individual explores a broader range of movement solutions and perceptual information.

Although researchers have assessed the utility of employing an external versus an internal focus of attention on subsequent performance and motor learning, little data directly compares the CLA with these other instructional methods. Therefore, the purpose of this study was to compare the launch angle, bat velocity, number of fly balls, variability of bat path angle at the point of contact, and bat path angle following interventions that used an internal focus of attention, an external focus of attention, and a CLA.

Correctness

The study had a relatively decent sample size (n=42 experienced baseball position players). The author also used virtual reality software (that provided tactile and audio feedback to simulate contact with the ball) to train participants. The main strength of this setup, relative to using a pitching machine, is that participants watched a simulated pitcher throw the baseball, which is more ecologically valid than only seeing a ball release from a device. All pitches were four-seam fastballs with a backspin of 1900 rpm and a linear velocity of 88 plus-or-minus 2 mph. The lateral and vertical positions of the pitches varied between 45-65cm of the participants' waist and 20cm above and below the midpoint of their strike zones, respectively. Although the researcher only used one pitch type, there was still enough variability to get a decent sense of how these results may transfer to actual sporting settings. Furthermore, the author used instructions implemented in the field, so any claims of a strawman argument (e.g., claiming that the internal focus of attention induced is not realistic to what coaches would say in practice) are unfounded.

There were also several limitations that the author outlined at the end of the article. First, future research should use different pitch types to mimic the demands of the sport better. Second, the author did not measure swing kinematics were, and thus we have a limited picture of how participants explored the perceptual-motor landscape. Third, there was no explicit control group.

Contributions

• The external focus of attention group and the CLA group showed significantly greater improvements in their launch angles, fly balls, exit velocity, and the number of home runs.
• The bat variability of the internal focus of attention group was the same pre-and post-intervention. However, the external focus of attention group and the CLA group showed significant variability increases after the first blocks of training, which then reduced toward the end of training. These findings suggest these groups explored more of the perceptual-motor landscape during practice (as would have been predicted by theory).
• Unexpectedly, the CLA group resulted in significantly greater improvements than the external focus of attention group after training. This finding may have been because the CLA group was encouraged to explore relatively more of the perceptual-motor landscape than the external focus of attention group (as demonstrated by the significantly greater bat path variability in the CLA group).
• Although the author tailored the study specifically for baseball, it highlights the general importance of encouraging exploration and variability during training to facilitate skill acquisition. The facilitation of these general objectives is also likely important for strength coaches and rehabilitation professionals that aim to ensure their clients transfer movement behaviours beyond the gym or clinic.

🧠 Fun fact of the week

Hundreds of millions of years ago, bacteria had not yet evolved to decompose fallen trees, and thus trees weren't biodegradable! Therefore, when they would fall and die, they would "sit there" rather than decay as they do now. The result of this? Large piles of dead wood, leading to massive forest fires and, by extension, most of the coal on earth today. Neat!

📚 Book recommendation

I am mixing it up this week and sharing a book recommendation instead! I've recently read "How We Learn to Move" by Dr. Rob Gray (the author of the paper above). I've enjoyed how Dr. Gray breaks down the differences between the two main branches of motor control, the theory underpinning the CLA, and highlighting some critical studies and concepts in a digestible way for practitioners. I'd highly recommend checking it out:

Please note that if you plan to purchase the book, consider using the affiliate link above as it costs you no extra money, and Amazon provides a little kickback for me. This will help me continue providing content 😊.

🗣 Quote of the week

"When you are distressed by an external thing, it's not the thing itself that troubles you, but only your judgement of it. And you can wipe this out at a moment's notice"

- Marcus Aurelius, Meditations, 8.47