Vertical Drop Jump Biomechanics of Patients With a 3- to 10-Year History of Youth Sport-Related Anterior Cruciate Ligament Reconstruction.

Background: A better understanding of movement biomechanics after anterior cruciate ligament reconstruction (ACLR) could inform injury prevention, knee injury rehabilitation, and osteoarthritis prevention strategies.

Purpose: To investigate differences in vertical drop jump (VDJ) biomechanics between patients with a 3- to 10-year history of youth sport-related ACLR and uninjured peers of a similar age, sex, and sport.

Study Design: Cross-sectional study.

Reliability of the knee muscle co-contraction index during gait in young adults with and without knee injury history.

Despite the frequent use of the electromyography-based muscle co-contraction index (CCI) to examine muscular control of the knee joint in young adults with and without knee injury history, the reliability of the CCI in this population is unknown. The purpose of this study was to quantify within-day and between-day reliability of the knee muscle CCI during gait in young adults with and without knee injury history. Twenty young adults (10 males, 10 females) with and without history of intra-articular knee injury performed repeated gait analyses on two different days.