Effort percentages are everywhere in throwing programs. Catch play at 60%, recovery day at 50%. The numbers sound precise, and they almost never are. Across several biomechanics studies, pitchers asked to throw at reduced effort kept most of their arm stress while giving up only a modest slice of velocity. That matters for anyone building a week around high and low days, because a low day that is secretly a medium-high day breaks the whole plan.
What the research shows about perceived effort
Long toss: Melugin and colleagues, 2019
Sixty high school and college pitchers threw long toss at 120 feet wearing an arm sensor, with velocity measured by radar. At what they called 50% effort, they still threw at 78% of their max velocity and produced 87% of their max elbow varus torque. At "75%," torque was 93% of max [1]. Each 25% drop in perceived effort cut torque by only about 7%.
From the mound: Slenker and colleagues, 2014
Twenty-nine college pitchers were measured with motion capture. At 60% perceived effort from the mound, they threw about 84% of their max velocity with about 76% of their max shoulder and elbow loads [2].
High school pitchers: Fiegen and colleagues, 2023
Ten high school pitchers threw from a mound at full, 75% and 50% effort with marker-based motion capture. At 50% effort, elbow stress was 75% of max and velocity was 85% [7]. The authors summarized it neatly: for every 25% cut in perceived effort, elbow stress fell by about 13% on average.
High school and pro pitchers: Hyeamang and colleagues, 2026
The newest study compared 38 high school and 24 professional pitchers and found the same pattern at both levels: reduced perceived effort produced far less reduction in elbow varus torque and velocity than the number suggests [3]. Reinold and colleagues, building a workload-based interval throwing program, likewise note that 50% effort on the mound corresponds to roughly 80% to 85% of max velocity [9].
| Study | Pitchers | "Effort" asked | Velocity (% of max) | Arm load (% of max) |
|---|---|---|---|---|
| Melugin 2019 [1] | 60 HS and college, long toss | 50% | 78% | 87% elbow torque |
| Slenker 2014 [2] | 29 college, mound | 60% | ~84% | ~76% shoulder and elbow |
| Fiegen 2023 [7] | 10 high school, mound | 50% | 85% | 75% elbow stress |
The studies differ in age and measurement method, and the samples are small. They agree on the direction. Perceived effort overshoots, and arm stress falls more slowly than the label implies.
Why does 50% feel like 50%?
Effort is a sensation, and a throw is a ballistic skill your body has organized around one speed for years. When you "back off," you mostly soften the lower half and ease the finish, while the arm still whips through a similar path. The ball slows a bit. The elbow still sees much of the same load. The research does not fully explain the mechanism, and individual pitchers vary, but the practical upshot is clear: your sense of effort is a poor dial for arm stress.
Driveline's workload thinking adds a second point. In a recent video, a Driveline trainer describes the intensity-fatigue relationship as non-linear: fifty throws at 100% fatigue the arm more than a hundred at 50% [10]. That is practitioner reasoning, and it fits the sensor data. The top of the effort scale is where cost piles up, and "medium" throws sit closer to the top than they feel.
Intent you can trust
Track the intent of every set
Pitch AI tracks the intent of every throwing set, so your easy days and hard days are actually different, and every session feeds a workload log that builds progressively.
The fix: a velocity ceiling, measured
The cleanest evidence for a fix comes from a simulation study of return-to-throw rehab. Lizzio and colleagues had 37 pitchers throw at 50% and 75% effort and then at radar targets of 50% and 75% of their max velocity. The radar-guided throws produced less elbow torque than the effort-guided ones, and each 10% drop in velocity came with roughly a 13% drop in torque [4]. The authors recommend using a radar gun to guide partial-effort throwing. For the training side of the gun, see does using a radar gun help you throw harder?.
So give easy days a number instead of a feeling. If your max is 80 mph and today calls for 70%, the ceiling is 56 mph. Stay under it, even when it feels almost too easy. The first few sessions will feel strange, because 56 mph will feel like 40% effort. That feeling is the point.
How to set a velocity ceiling
- Use a recent max. Take your best velocity from the current phase, from the same kind of throw (mound or flat ground).
- Multiply by the day's target. A 60% recovery day on an 80 mph max is 48 mph. A 75% hybrid day is 60 mph.
- Check a few throws, not every throw. Gun the first several throws of each block to calibrate, then spot-check.
- Without a gun, go lower than feels right. If you only have feel, aim well below the effort number you were given, since every study points the same way.
Measure the high days too
The same honesty runs the other way. On velocity days, a measured max keeps you from coasting. Lifting research shows why that matters. In Behm and Sale's classic study, trying to contract as fast as possible produced high-velocity strength gains even when the limb could not move at all; the intent itself was the stimulus [6]. In bench press training, lifting every rep as fast as possible produced larger strength and speed gains than lifting the same loads deliberately at half speed [5], and a squat study found a similar advantage for fast intent [8].
Our post on intent in pitching goes deeper on this research. Those are lifting and isolated-muscle studies. They support the principle that intent is a training signal. They do not prove that max-intent throwing adds velocity by itself, and throwing-specific velocity evidence is more mixed. Still, the lesson for programming holds: a velocity day where you never truly reach max is a wasted high day, and a recovery day spent at 85% is a wasted low day. Driveline says it is more likely to get upset with an athlete for throwing too hard on a recovery day than for not throwing hard enough on a velocity day [11].
When lower intent is the right call
None of this means every throw should be hard. Low intent has real jobs. Recovery days exist to move blood and keep feel without adding meaningful load, and Driveline programs them at low intent on purpose [11]. On-ramp weeks after time off rebuild throwing fitness before any 100% days appear [11], which our guide to progressing a throwing program walks through. Moderate effort also helps when you are learning a new movement: Driveline uses long toss partly so athletes can regulate their own effort while new mechanical patterns settle in, before proving those patterns hold at full intent [11].
In every one of those cases, the measured number matters more than the feeling. A recovery day is only a recovery day if the arm actually sees recovery-level stress, and the studies above show how easy it is to miss that by feel alone.
Effort, workload and your arm
If perceived effort overshoots, then any workload log that records "50% day, 40 throws" is undercounting. That is one more reason to count every throw and to watch trends over weeks. Our guide to pitching workload and arm health covers acute and chronic load, and long toss for pitchers shows how distance and trajectory change stress. If you are coming back from injury, follow your clinician's interval program and ask how they want intensity measured.
What to do this week
Find your current max from the same type of throw. Write a velocity ceiling for every low and moderate day this week. On your high day, chase a real number and stop when quality drops. Then compare how your arm feels on Friday with how it felt last week. Part 4 puts all of this into a full weekly training schedule. For the bigger picture, start with Part 1 on offseason planning.
Frequently asked questions
Is throwing at 50% effort really 50% of the stress?
No. In sensor and motion-capture studies, throws at 50% perceived effort still produced about 75% to 87% of maximum elbow torque at roughly 78% to 85% of maximum velocity.
How do I throw at a true 50% or 70%?
Use a velocity ceiling instead of a feeling. Multiply a recent max velocity by the day's target percentage and stay under that number on a radar gun. A study of rehab throwing found radar-guided throws produced less elbow torque than effort-guided ones.
Why does throwing easy still make my arm sore?
Because reduced-effort throws keep much of their arm stress. Each 25% drop in perceived effort cut elbow torque by only about 7% in one long toss study, so a lot of 'easy' throws can add up to real workload.
Should pitchers measure velocity on hard days too?
Yes. A measured max keeps velocity days honest, and lifting research shows that the intent to move fast is itself a training signal. Stop the high-intent work when quality or velocity clearly drops.
Easy days that stay easy
Keep your low days low with Pitch AI
Pitch AI tracks set-by-set intent and shows your acute-to-chronic workload trend. A daily Wellness Check-In for arm freshness, soreness and pain can reduce volume on days your arm is telling you to back off.
References
- Melugin HP, Larson DR, Fleisig GS, et al. Baseball pitchers' perceived effort does not match actual measured effort during a structured long-toss throwing program. American Journal of Sports Medicine. 2019;47(8):1949-1954. doi:10.1177/0363546519850560
- Slenker NR, Limpisvasti O, Mohr K, Aguinaldo A, ElAttrache NS. Biomechanical comparison of the interval throwing program and baseball pitching: upper extremity loads in training and rehabilitation. American Journal of Sports Medicine. 2014;42(5):1226-1232. doi:10.1177/0363546514526152
- Hyeamang LJ, Dowling B, Hodakowski A, et al. The influence of rate of perceived effort on pitching mechanics and elbow varus torque in high school and professional pitchers. Orthopaedic Journal of Sports Medicine. 2026;14(1):23259671251374296. doi:10.1177/23259671251374296
- Lizzio VA, Smith DG, Jildeh TR, et al. Importance of radar gun inclusion during return-to-throwing rehabilitation following ulnar collateral ligament reconstruction in baseball pitchers: a simulation study. Journal of Shoulder and Elbow Surgery. 2020;29(3):587-592. doi:10.1016/j.jse.2019.08.014
- González-Badillo JJ, Rodríguez-Rosell D, Sánchez-Medina L, Gorostiaga EM, Pareja-Blanco F. Maximal intended velocity training induces greater gains in bench press performance than deliberately slower half-velocity training. European Journal of Sport Science. 2014;14(8):772-781. doi:10.1080/17461391.2014.905987
- Behm DG, Sale DG. Intended rather than actual movement velocity determines velocity-specific training response. Journal of Applied Physiology. 1993;74(1):359-368. doi:10.1152/jappl.1993.74.1.359
- Fiegen AP, Nezlek SP, Loushin SR, et al. Changes in elbow stress and ball velocity during reduced effort pitching: a marker-based motion capture analysis. American Journal of Sports Medicine. 2023;51(3):779-785. doi:10.1177/03635465221144020
- Pareja-Blanco F, Rodríguez-Rosell D, Sánchez-Medina L, Gorostiaga EM, González-Badillo JJ. Effect of movement velocity during resistance training on neuromuscular performance. International Journal of Sports Medicine. 2014;35(11):916-924. doi:10.1055/s-0033-1363985
- Reinold MM, Dowling B, Fleisig GS, et al. An interval throwing program for baseball pitchers based upon workload data. International Journal of Sports Physical Therapy. 2024;19(3):326-336. doi:10.26603/001c.94146
- Driveline Baseball. "What 1,000 Bullpen Days Told Us About Pitch Counts." YouTube, 2026-10-10. youtu.be/5OZjHuvBtiY
- Boddy K, Daniels M. Hacking the Kinetic Chain: Advanced Pitching. Driveline Baseball; 2017. Chapter 3.1, Throwing Programming.