Most pitching instruction treats the delivery as something you do to the ball. Perception-action research treats it as something you do in response to information: the catcher's setup, the hitter's stance, the count, the flight of the last pitch. Those two views lead to very different bullpens. This article explains the second one and what it means for how you practice.

What are affordances in pitching?

Psychologist James Gibson coined the term affordances for the possibilities for action that an environment offers, perceived relative to your own body and abilities [1]. Fajen, Riley and Turvey later applied the idea to sport, arguing that athletes perceive action possibilities scaled to their own capabilities and control movement using information picked up while they move [2].

For a pitcher, a catcher set up low and away offers a different throw than a catcher sitting middle. A left-handed hitter crowding the plate offers something different again. Your body organizes itself around what is offered, often without any conscious decision. That is why the information present in practice matters: change it, and you may change the movement you are rehearsing.

How do pitchers use ball flight to adjust?

Perception and action work as one loop. You see the target, organize the throw, read the ball flight and adjust the next one. Kusafuka and colleagues measured this directly in 14 skilled pitchers throwing 30 pitches each. Pitchers corrected their release-angle errors from one pitch to the next, and the size of the correction depended on the direction of the previous error. Pitchers with larger release-angle variability made fewer horizontal corrections [3].

Illustrative: the loop behind every pitch. Skilled pitchers corrected their release angle errors from one pitch to the next. Source: [3] Kusafuka et al. 2025

In practical terms, every pitch is a measurement for the next one, but only if you can see where it went. A throw into a net two feet away gives the loop almost nothing to work with.

What the batting and cricket research shows

Most of the strongest evidence comes from hitters and batters reading pitchers and bowlers. Keep that in mind, because it is evidence about the principle more than about pitchers specifically.

  • Machines change the movement. In developing cricketers facing a bowling machine and a live bowler at matched speed, batters started their movements earlier and took a longer step against the live bowler [8]. In skilled batters, removing the bowler's action delayed movement initiation and lowered contact quality, and video without real ball flight changed downswing timing [9].
  • Practice should sample the game. Pinder, Davids, Renshaw and Araújo proposed representative learning design: training should keep the key links between information and movement that athletes use in competition [5]. They also argue machines and simplified tasks have a role when they are used with clear principles about when and why [12].
  • Adaptive practice transferred. In Gray's 2017 study of 80 high school hitters, the group whose virtual pitches adapted in speed, type and location to their success improved most, including on an on-field test and league statistics the following season [6]. It is a single study from one lab and needs replication.
  • How information is delivered matters. In a small simulated-batting study, hitters handed all of a pitcher's tendencies did best at first. Hitters who discovered the patterns themselves caught up quickly and handled a brand-new pitcher best [4].
Simulated batting. Hitters who discovered a pitcher's tendencies themselves adapted best when they faced someone new. Source: [4] Gray 2015
Developing cricketers facing a machine and a live bowler at matched speed moved differently, because the bowler's action carries information the machine does not. Source: [8] Pinder, Renshaw and Davids 2009
Where the pitching evidence is thin

We found no controlled study comparing pitcher kinematics or command with and without a live hitter. One study comparing lab and game pitching found within-pitcher variability was similar in both settings, although pitchers typically throw slower in the lab and the comparison used different pitchers and capture systems [10]. The case for game-like bullpens is a reasoned extension of the batting work.

Does what a pitcher looks at change how they throw?

Yes, and there is pitching-specific evidence for this one. Gray, Orn and Woodman found that under pressure, pitchers given only a target showed changes in expertise-related kinematics, and pitchers who were also shown an "avoid" zone threw more pitches into it [11]. What you are told to look at and think about is part of the information your delivery responds to. Give pitchers a clear target, and keep "don't leave it middle" out of the vocabulary.

Read the ball flight

Log what every pitch actually did

Pitch AI's Pitch Lab logs velo, IVB, spin, axis and release for every pitch, and its movement chart shows how each pitch shape compares with the rest of your arsenal. That turns ball flight into information you can act on from one session to the next.

Download on the App Store Get it on Google Play

The problem with only throwing into a net

The Rubicon podcast makes a sharp practitioner point here. When home plate is always in the corner of a net with no space behind it, a pitcher may never see a truly wild throw all winter. The host argues that many pros "zoo" their first ball of spring training for exactly that reason, and that every throw should be information-dense, thrown far enough to see the flight [7]. That is coaching opinion, but it lines up with the error-correction loop Kusafuka measured: no visible flight, no correction.

A net has its place. High-volume work, technical exploration, arm care and winter throwing in a small space all have value, and our guide to pitching drills at home covers how to use one well. The point is to regularly re-couple the delivery to game information, so the loop you train is the loop you use.

How to keep perception and action connected in practice

  • Move the glove. Have the catcher set real targets and move them between pitches instead of sitting middle.
  • Call pitches by count. Start at 0-0, let a coach or catcher call balls and strikes, and try to finish each simulated at-bat. Track zone rate and miss distance by count.
  • Add a hitter when it is safe. A stand-in hitter in a helmet who tracks pitches without swinging, alternating sides, adds key information. Use a protective screen where appropriate.
  • Read every ball flight. Throw far enough to see the flight in catch play, and treat each pitch's shape and location as feedback for the next one.

These are applications of the research rather than tested pitching protocols, so watch your own results. Mixing practice types is reasonable: blocked work on a screen for volume, then count-based bullpens that bring back the hitter and the moving glove. If you are building pitch shapes, our pitch design workflow ends with validating new shapes in a real baseball context, which is this same principle applied to pitch design.

Where this fits in the series

Perception-action coupling helps explain why a new pattern built only in sterile conditions can collapse in games, the subject of why pitchers go back to old mechanics in games. The next part asks whether great pitchers really repeat the same motion every time: movement variability and entropy explained. Parents and coaches of younger pitchers can find the bigger developmental picture in our guide to youth pitcher development.

Frequently asked questions

What is perception-action coupling?

It is the idea that perceiving and moving work as one loop. You pick up information, such as the target and the last ball flight, and organize the movement around it. Skilled pitchers measurably correct release angle from pitch to pitch based on where the last pitch went.

Is pitching a closed skill?

It is often called one because there is no defender to beat, but pitchers still respond to the catcher's setup, the hitter, the count and ball flight. Those cues shape how the delivery is organized.

Should pitchers throw bullpens with a hitter in the box?

It is a reasonable idea supported by batting and cricket research showing that removing key information changes movement. There is no controlled pitching study yet, so use a safe stand-in hitter and watch your own command data.

Is throwing into a net bad for command?

Not by itself. Nets are useful for volume and exploration. The concern, raised by practitioners, is that a pitcher who only throws into a net never sees full ball flight or a truly wild miss, so mix in throws where the flight is visible.

Keep perception and action connected

Turn every bullpen into information

Pitch AI's Pitch Lab logs velo, IVB, spin, axis and release for every pitch, and Pitch AI builds dedicated Command days into your throwing program, so game-like target work has a regular place in your week.

Download on the App Store Get it on Google Play

Sources and further reading

  1. Gibson JJ (1979). The Ecological Approach to Visual Perception. Houghton Mifflin.
  2. Fajen BR, Riley MA, Turvey MT (2009). Information, affordances, and the control of action in sport. International Journal of Sport Psychology 40(1):79-107. https://www.ijsp-online.com/abstract/view/40/79
  3. Kusafuka A, Okegawa T, Yamamoto R, Miyata K, Kudo K (2025). Two-dimensional trial-by-trial error correction for accurate baseball pitching. Scientific Reports 15:12300. https://doi.org/10.1038/s41598-025-97146-5
  4. Gray R (2015). The Moneyball problem: what is the best way to present situational statistics to an athlete? Proceedings of the Human Factors and Ergonomics Society Annual Meeting 59(1):1377-1381. https://doi.org/10.1177/1541931215591230
  5. Pinder RA, Davids K, Renshaw I, Araújo D (2011). Representative learning design and functionality of research and practice in sport. Journal of Sport & Exercise Psychology 33(1):146-155. https://doi.org/10.1123/jsep.33.1.146
  6. Gray R (2017). Transfer of training from virtual to real baseball batting. Frontiers in Psychology 8:2183. https://doi.org/10.3389/fpsyg.2017.02183
  7. Rubicon (2026). Casting The Die, Episode 2, with Steffen Simmons. YouTube, September 19, 2026. Practitioner podcast. https://youtu.be/PkRCz3dhYn0
  8. Pinder RA, Renshaw I, Davids K (2009). Information-movement coupling in developing cricketers under changing ecological practice constraints. Human Movement Science 28(4):468-479. https://doi.org/10.1016/j.humov.2009.02.003
  9. Pinder RA, Davids K, Renshaw I, Araújo D (2011). Manipulating informational constraints shapes movement reorganization in interceptive actions. Attention, Perception, & Psychophysics 73(4):1242-1254. https://doi.org/10.3758/s13414-011-0102-1
  10. Lerch BG, Fleisig GS, Slowik JS, Oliver GD (2025). Variability of in-game markerless and laboratory marker-based baseball pitching biomechanics. Journal of Biomechanics 188:112775. https://doi.org/10.1016/j.jbiomech.2025.112775
  11. Gray R, Orn A, Woodman T (2017). Ironic and reinvestment effects in baseball pitching: how information about an opponent can influence performance under pressure. Journal of Sport & Exercise Psychology 39(1):3-12. https://doi.org/10.1123/jsep.2016-0035
  12. Pinder RA, Renshaw I, Davids K, Kerhervé H (2011). Principles for the use of ball projection machines in elite and developmental sport programmes. Sports Medicine 41(10):793-800. https://doi.org/10.2165/11595450-000000000-00000

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