Pitching Mechanics / Injuries / Thrower Info

Question 1

What are the best predictors of injury with pitchers?

Answer 1

1. Previous injury
2. Pitching fatigue

Question 2

Differences that contribute to increased force production between older and younger pitchers?

Answer 2

As getting older they are throwing harder but mechanics are not changing. Some of the mechanics can be developed from 8-10 years old.

Question 3

Wind Up

Answer 3

• Preparation for force generation
• Lift lead leg
• Minimal EMG

Question 4

Stride Phase

Answer 4

• Starts when hand leaves glove
• Initiate velocity with a step
• Lead foot moves forward
• Pelvis rotates towards home plate

Question 5

Cocking

Answer 5

• Transfer of energy from LE to trunk
• Begins with front foot strike
• Torso rotates towards one plate
• Shoulder abd and elevation, starting to go into ER
• You’re winding of the shoulder and storing potential energy

Late Cocking: UT/SA acting to elevate shoulder, eccentric control from IR’s

Question 6

Acceleration

Answer 6

• Transfer energy onto ball
• Start of IR
• Elbow starts to extend, wrist starts to flex
• Shoulders coming forward to face home plate
• Still eccentric control c IR

Question 7

Deceleration

Answer 7

• Starts at ball release
• Lots of distraction on arm
• Lots of eccentric control from ER’s, periscapular mm

Question 8

Follow Through

Answer 8

• Arm crosses the body
• Forward trunk flexion
• Need to be ready to field

Question 9

Critical Points in Throwing

Answer 9

1. Late cocking
   - Peak shoulder rotation torque
   - Peak elbow valgus torque
   - Critical for SLAP and UCL tears
2. Deceleration
   - Peak compressive forces several times body weight
   - excessive mm activation (RTC and periscapular)
   - Muscle forces about 1.5 times body weight

Question 10

What are the KINETIC variables most related to injury with pitching?

Answer 10

• Elbow valgus torque
• Shoulder ER torque
• Pitch velocity

Question 11

KINEMATIC variable related to KINETIC problems?

Answer 11

1. Knee flexion angle (should be 38-50 at foot contact)
   - Too much decreases effectiveness of throw
   - Too little and you don’t transfer force to leg (more shoulder/elbow torques)
2. Trunk rotation (Pelvis rotates before trunk but generally accepted that trunk should not start to turn before foot contact)
   - There should be separation between pelvis rotating and trunk rotation
   - Peak pelvis rotation (from 0% at foot contact to 100% at release) occured at 28-35% and peak trunk at 47-53%
   - If you open up too soon it’s flying open at the shoulders
3. Elbow flexion when releasing ball
   - There is less variability amongst pitchers
   - More elbow flexion = more elbow torque

Question 12

5 varialbles associated with most increase in kinetic variables on the body?

Answer 12

3 or more of these was associated with less torque on elbow and shoulder and improved pitching efficiency.

1. Leading with the hips (going into stride phase), hips move first instead of the upper body to use lower body generation
2. Hand on top position (coming out of glove)
3. Elbow stays high through stride and early cocking
4. Closed shoulder position (can’t see chest at foot contact)
5. Lead foot towards home plate

Question 13

Pitch Count Numbers and Rest

Answer 13

Question 14

Positions most provocative in OH throwers

Answer 14

1. Fully ER’d/cocked position
2. Ball release

Question 15

What happens to ROM in pitchers after they throw?

Answer 15

IR decreases by several degrees immediately after but ER not affected. Likely due to large forces during pitching from ER’s.

Question 16

Why do throwers have changes in their ER ROM?

Answer 16

Likely due to osseous adaptations in the humeral phases of the young athlete’s shoulder that leads to humeral head retroversion.

Question 17

Stretching Program During Season and Effect on ROM?

Answer 17

Stretching program that did 3-5 reps of 10 seconds in flex, ER/IR at 90, and H ADD. Actually gained 5 degrees of IR, no change in ER.

Question 18

Are we seeing posterior capsule tightness in baseball players with limited IR?

Answer 18

No. Bursa use an objective mechanical translation device to look at anterior and posterior laxity.

Posterior laxity was significantLT greater than anterior capsular laxity, despite gross limitations of passive/active IR. Also, translation was equal bilaterally.

Question 19

Scapular Position For Thrower’s Arms (Side/Side)

Answer 19

Dominant side of asymptomatic thrower is more protracted, depressed, and anteriorly tilted compared to non-throwing side.

Question 20

Isokinetic testing of IR and ER for throwers on dominant and non dominant sides?

Answer 20

ER for dominant side actually lower than non-dominant side, IR greater.

Question 21

When does torsional change in humerus occur for pitchers?

Answer 21

Starts as early as 8 and progresses until growth plate closes in proximal humerus.

Question 22

Ages to start throwing pitch types?

Answer 22

Fastball = 8
Change Up = 10
Curveball = 14
Slider = 16