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. 2019 Jul 29;7:e7390. doi: 10.7717/peerj.7390

Table 3. Kinematic changes with fatigue.

A summary of selected pitching kinematic changes following various fatigue protocols.

Study Sample size Fatigue protocol Changes in kinematics due to fatigue Pre–post fatigue change
Escamilla et al. (2007) 10 collegiate pitchers 15 pitches per inning for seven to nine innings

  • - Change in trunk flexion during the arm cocking and acceleration phase (from 34° ± 12° to 29° ± 11°)

  • - 5° change in trunk flexion
Murray et al. (2001) Seven major league pitchers No protocol, collection during games

  • - Decreased maximum shoulder external rotation (181° in the first inning to 172° in the last)

  • - Decreased knee angle at ball release (140° in first inning to 132° in the last)

  • - 9° change in maximum external rotation

  • - 8° change in knee angle
Erickson et al. (2016) 28 adolescent pitchers Warmup followed by 15 pitches per inning for six innings

  • - Hip-to-shoulder separation decreased as pitch count increased (from 90% ± 40% at pitch 15 to 40% ± 50% at pitch 90; p < 0.001)

  • - Knee flexion increased with pitch number (from 49° ± 15° to 53° ± 15°, p = 0.008)

  • - Increased shoulder external rotation and total range of motion post pitching

  • - Lower half muscles fatigued before changes in upper extremity kinematics occurred

  • - 50% change in hip-to-shoulder separation

  • - 4° change in knee flexion
Mullaney et al. (2005) 13 university pitchers 99 pitches over seven innings

  • - Postgame results showed selective fatigue of 15% in shoulder flexion (p = 0.02); 18% in shoulder internal rotation (p = 0.03); and 11% in shoulder adduction (p = 0.01)

  • - N/A
Keeley, Barber & Oliver, 2010 10 collegiate pitchers Five pitches for strikes followed by two kg ball throws until maximum perceived fatigue

  • - Changes in lateral pelvis tilt at maximum external rotation (from −10.8° ± 11.8° to −14.8° ± 11.3°) and ball release (from −3.36° ± 5.24° to −6.82° ± 3.87°) between non-fatigued and fatigued conditions (p < 0.05) (negative represents tilt to left)

  • - 4° change in lateral pelvis tilt at maximum external rotation

  • - 3.5° change in lateral pelvis tilt at ball release
Chou et al. (2015) 16 high school pitchers 10 maximum effort fastball warmups, 100 pitches, 10 pitches post throwing session

  • - Increased knee flexion (from 53.6° ± 21.5° to 56.1° ± 22.2°; p = 0.01) and trunk flexion (from 21.4° ± 5.4° to 24.2° ± 6.6°; p = 0.01) at instant of ball release

  • - Shoulder horizontal abduction decreased at the instant of front foot strike (from 21.1° ± 11.0° to 18.7° ± 10.1°; p = 0.01)

  • - Maximum forearm pronation decreased during the acceleration phase (from 27.4° ± 12.3° to 22.4° ± 10.6°; p = 0.01)

  • - Elbow valgus (8.8° ± 3.3° to 6.9° ± 3.9°; p = 0.01) and forearm pronation (24.9° ± 11.2° to 20.1° ± 8.9°; p = 0.01) decreased at ball release as fatigue accumulated

  • - 2.5° change in knee flexion at ball release

  • - 2.8° change in trunk flexion at ball release

  • - 2.4° change in horizontal abduction at front foot strike

  • - 5° change in forearm pronation during acceleration

  • - 1.9° change in elbow valgus angle at ball release

  • - 4.8° change in forearm pronation at ball release
Oliver & Plummer (2010) 14 high school pitchers Five pitches for strikes followed by two kg ball throws until maximum perceived fatigue

  • - Kinematic data was collected, but results were not shown within the study’s results

  • - N/A
Oliver, Weimar & Henning (2016) 23 youth pitchers 75 pitch limit

  • - Kinematic data was collected, but results were not shown within the study’s results

  • - N/A
Tripp, Yochem & Uhl (2007) 16 collegiate pitchers Three to five warmup pitches, throwing every 5 s until maximum perceived fatigue

  • - Arm cocked position changed from 12.4 mm pre-fatigue to 24.1 mm post-fatigue (decreased acuity)

  • - Ball release position changed from 20.8 mm pre-fatigue to 41.7 mm post-fatigue (decreased acuity)

  • - 11.7 mm change in joint position sense in arm cocked position

  • - 20.9 mm change in joint position sense at ball release
Grantham et al. (2014) 11 collegiate pitchers No protocol, collection during games

  • - Increased hip flexion at hand separation (p = 0.022)

  • - Increased hip flexion (p = 0.002) and shoulder lateral tilt (p = 0.048) at maximum external rotation was observed in innings in which the pitcher threw over 15 pitches

  • - N/A