Changes in Lower Extremity Kinematics and Temporal Parameters of Adolescent Baseball Pitchers During an Extended Pitching Bout.
BACKGROUND
Few studies have investigated detailed 3-dimensional lower extremity kinematics during baseball pitching in adolescent athletes during extended play. Changes in these parameters may affect performance outcomes.


OBJECTIVE
To investigate whether adolescent baseball pitchers experience changes in lower extremity kinematics and event timing during a simulated game-length pitching bout.


METHODS
Descriptive laboratory study.


METHODS
Twelve male adolescent pitchers (aged 14-16 years) threw 6 sets of 15 fastball pitches from an artificial pitching mound to a target at regulation distance. Joint angles and angular velocities at the hip, knee, and ankle of both legs were collected throughout the phases of the pitching cycle as well as stride length, pelvis orientation, pitch duration, timing of foot contact and ball release, ball speed, and pitching accuracy. Paired t tests ( P < .05) were used to compare the dependent variables between the last 5 pitches of the second (baseline) and sixth (final) sets.


RESULTS
During the stride phase, decreased maximum angular excursions for hip extension (baseline: 14.7° ± 9.8°; final: 11.6° ± 10.3°; P < .05) and ankle plantar flexion (baseline: 30.2° ± 14.5°; final: 24.2° ± 15.3°; P < .05) as well as maximum angular velocity for knee extension (baseline: 144.9 ± 63.3 deg·s-1; final: 121.7 ± 62.0 deg·s-1; P < .05) were observed between sets in the trailing leg. At foot contact, pitchers had decreased hip flexion (baseline: 69.5° ± 10.1°; final: 66.5° ± 11.8°; P < .05) and increased hip abduction (baseline: 20.7° ± 8.9°; final: 25.4° ± 6.0°; P < .05) in the leading leg in the final set. Compared with the baseline set, ball speed significantly decreased in the final set (29.5 ± 2.5 m·s-1vs 28.3 ± 2.5 m·s-1, respectively; P < .05).


CONCLUSIONS
Kinematic changes and decreased ball speeds observed in the final set suggest that adolescent pitchers are unable to maintain lower extremity kinematics and performance as a result of extended play.


CONCLUSIONS
The results from this study may warrant further investigation into how altered lower extremity kinematics may affect trunk and upper extremity function, performance, and risk of injuries during pitching in adolescent athletes, particularly during actual game play.
Massey University, Wellington, New Zealand.
Stacey M
SM
Kung
Massey University, Wellington, New Zealand.
Sarah P
SP
Shultz
Hospital for Special Surgery, New York, New York, USA.
Andreas
A
Kontaxis
Hospital for Special Surgery, New York, New York, USA.
Andrew P
AP
Kraszewski
Hospital for Special Surgery, New York, New York, USA.
Mandi W
MW
Gibbons
Hospital for Special Surgery, New York, New York, USA.
Sherry I
SI
Backus
Massey University, Wellington, New Zealand.
Philip W
PW
Fink
Hospital for Special Surgery, New York, New York, USA.
Stephen
S
Fealy
Hospital for Special Surgery, New York, New York, USA.
Howard J
HJ
Hillstrom
D000293:Adolescent; D001484:Baseball; D001696:Biomechanical Phenomena; D006801:Humans; D035002:Lower Extremity / Q000502:physiology*; D008297:Male; D064797:Physical Conditioning, Human
baseball; fastball; performance; pitching mechanics