This study investigated the differences in joint motions and muscle activities of the lower extremities involved in various squatting postures.
The study targeted the catcher in order to clarify motion dissimilarities when throwing with various squatting posture widths and techniques for delivering the ball.
Twelve baseball catchers were recruited for this purpose.
All participants reported no history of low back pain or other musculoskeletal problems within the previous 3 years and were required to complete a questionnaire with a complementary interview regarding the practice of physical and sporting activities prior to the trial.
The motion capture system with thirty-one reflective markers attached on participants was used for motion data collection.
The electromyography system was applied over the quadriceps, biceps femoris, tibialis anterior and gastrocnemius muscles of the pivot and stride leg.
The authors observed that in the acceleration phase, the lower limbs demonstrate similar patterns in various squatting positions and throw types.
The stride foot in the acceleration phase maintains a consistent hip-joint angle to support the weight of the ball movement and body balance.
Weight-shift throwing motions achieve twice the forward driving force, and faster ball speed.
Knee extension at the ball-catch instant in weight-shift throwing resulted in maximum muscle activation of the hamstrings of the pivot foot during the stride phase.
This directly influenced the driving force of the pivot foot.
Based on the findings of the study, the authors concluded that training design for strengthening the lower extremity muscles should consider the appropriateness of the common squat width to enhance squat-up performance.
For lower limb muscle activation, wide squatting requires more active gastrocnemius and tibialis anterior muscles.
Baseball players should extend the knee angle of the pivot foot before catching the ball.
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