Most youth arm injuries follow the same story: too many pitches, too little rest, and a tired arm that kept throwing. The research is not perfect, but it points one way. The rules that came out of it are simple enough to run from the dugout.
This page covers workload and rest only. It does not teach pitching mechanics or arm exercises. For those, see a qualified professional (more on that below).
What the studies found
Much of the youth pitching research comes from the American Sports Medicine Institute (ASMI) in Birmingham, Alabama, co-founded by orthopedic surgeon Dr. James Andrews. Two studies get quoted most.
The 10-year study. Fleisig and colleagues (2011) followed 481 pitchers who started the study at ages 9 to 14. Over ten years, 5% had a serious injury: elbow or shoulder surgery, or retiring from pitching because of injury. Pitchers who threw more than 100 innings in at least one year were 3.5 times more likely to be injured. Only 25 players were injured, so treat that exact multiplier loosely.
The risk-factor study. Olsen and colleagues (2006) compared 95 pitchers aged 14 to 20 who had shoulder or elbow surgery with 45 who had not. The injured group was far more likely to say they regularly pitched with a tired arm. Injury was also linked to pitching more than 8 months a year, more than 80 pitches per appearance, and fastballs over 85 mph.
Read the Olsen numbers with care. The study looked backward, relied on players remembering their habits, and studied high school and college-age pitchers, not 10-year-olds. The often-quoted “36 times” figure for pitching tired has a very wide margin of error. What holds up: pitching tired and pitching most of the year were both strong warning signs.
Why young elbows are different
In growing kids, the growth plate on the inside of the elbow is usually the weak spot, more than the ligament beside it. Repeated hard throwing can irritate or injure that growth plate. Doctors call it medial epicondyle apophysitis, better known as “Little League elbow.” The common first sign is pain on the inside of the elbow during or after throwing. Treatment usually starts with rest from throwing.
The rules: pitch counts and rest
MLB and USA Baseball's Pitch Smart guidelines and Little League's regular-season rules use the same daily limits for these ages. Your league may have its own rules, so check the rulebook too.
Daily maximum pitches:
- Ages 7 and 8: 50
- Ages 9 and 10: 75
- Ages 11 and 12: 85
- Ages 13 and 14: 95
Required rest for ages 14 and under (based on pitches thrown that day):
- 1 to 20 pitches: no rest day required
- 21 to 35 pitches: 1 day
- 36 to 50 pitches: 2 days
- 51 to 65 pitches: 3 days
- 66 or more: 4 days
Little League adds that no player may pitch on three consecutive days, and it limits moving between pitcher and catcher on the same day. Pitch Smart adds guidance for ages 9 to 12:
- No more than 80 innings pitched in any 12-month period.
- At least 4 months off from throwing each year, with 2 to 3 of those months in a row.
- Stick to fastballs and changeups.
- Avoid playing for more than one team at the same time.
These are limits, not targets. A pitch count only covers your games. If a player also pitches for another team, the arm does not know which uniform it was wearing.
What about curveballs?
The evidence is mixed. Lab studies of youth pitchers found the curveball did not put more stress on the elbow than the fastball (Dun et al., 2008). A survey study of 9 to 14-year-olds found more arm pain in players who threw curveballs and sliders (Lyman et al., 2002). Pitch Smart's answer for ages 9 to 12 is simple: fastballs and changeups. We follow that.
When to get help
Any arm pain means the player stops throwing for the day and the parents hear about it that day. Pain that comes back, or any elbow pain on the inside of the joint, should be checked by a doctor.
If a family wants a throwing program, arm-strength work, or help with mechanics, point them to a qualified professional: a sports medicine physician, or a licensed physical therapist or athletic trainer who works with throwing athletes.
Try this at your next game or practice
- Assign a pitch counter. One parent per game, one clipboard. Next to each pitcher's count, write the date they can pitch again.
- Ask before you hand over the ball. “Did you pitch for any other team this week?” Ask the parent too. Use the answer against the rest chart.
- Pull early on fatigue. If control falls apart, velocity drops, or the player shakes out or rubs the arm, the day is over. Pain means done, not “one more batter.”
- Grow the staff. Give five or six kids short turns on the mound in practice games, so no one arm carries the season.
- Plan the off-season now. At the end-of-season meeting, tell parents about Pitch Smart's 4 months off from throwing. Other sports are a great way to fill it.
Guidelines & sources
- MLB and USA Baseball (current). Pitch Smart guidelines, ages 9 to 12 and 13 to 14. Daily limits, rest days, 80-inning cap, 4 months off, fastballs and changeups.
- Little League International (current). Regular Season Pitching Rules. Pitch counts by league age, rest days, three-consecutive-days rule, pitcher and catcher limits.
- Fleisig, G. S., Andrews, J. R., Cutter, G. R., Weber, A., Loftice, J., McMichael, C., Hassell, N., & Lyman, S. (2011). Risk of serious injury for young baseball pitchers: a 10-year prospective study. American Journal of Sports Medicine, 39(2), 253-257. 481 pitchers, 5% seriously injured; more than 100 innings a year linked to 3.5 times the risk. Small number of injuries.
- Olsen, S. J., Fleisig, G. S., Dun, S., Loftice, J., & Andrews, J. R. (2006). Risk factors for shoulder and elbow injuries in adolescent baseball pitchers. American Journal of Sports Medicine, 34(6), 905-912. Case-control, ages 14 to 20. Pitching with arm fatigue, more than 8 months a year, and more than 80 pitches per game linked to surgery. Retrospective and older than our players.
- Lyman, S., Fleisig, G. S., Andrews, J. R., & Osinski, E. D. (2002). Effect of pitch type, pitch count, and pitching mechanics on risk of elbow and shoulder pain in youth baseball pitchers. American Journal of Sports Medicine, 30(4), 463-468. Curveballs and sliders linked to more arm pain in ages 9 to 14. Pain reports, not injuries.
- Dun, S., Loftice, J., Fleisig, G. S., Kingsley, D., & Andrews, J. R. (2008). A biomechanical comparison of youth baseball pitches: is the curveball potentially harmful? American Journal of Sports Medicine, 36(4), 686-692. Curveball did not produce higher elbow loads than the fastball in a lab. Small sample.
- StatPearls (NCBI Bookshelf). Medial Epicondyle Apophysitis (Little League Elbow). Growth plate overuse injury in young throwers; rest is first-line treatment.
Note on certainty: The link between heavy workload, pitching tired, and arm injury is consistent across studies, but most of it comes from observational research with small injury counts, so exact multipliers are rough. The pitch-count and rest rules are expert guidelines built on that research, not tested limits for every child. When in doubt, rest the arm.