Search

Background: Anterior cruciate ligament injuries (ACL) commonly occur during jump landing and cutting tasks. Attempts to landsoftly and land with greater knee flexion are associated with decreased ACL loading. However, their effects on performance areunclear.Hypothesis: Attempts to land softly will decrease peak posterior ground-reaction force (PPGRF) and knee extension moment atPPGRF compared with a natural landing during stop-jump and side-cutting tasks. Attempts to land with greater knee flexion atinitial ground contact will increase knee flexion at PPGRF compared with a natural landing during both tasks. In addition, bothlanding techniques will increase stance time and lower extremity mechanical work as well as decrease jump height and movementspeed compared with a natural landing during both tasks.Study Design: Controlled laboratory study.Methods: A total of 18 male and 18 female recreational athletes participated in the study. Three-dimensional kinematic andkinetic data were collected during stop-jump and side-cutting tasks under 3 conditions: natural landing, soft landing, and landingwith greater knee flexion at initial ground contact.Results: Attempts to land softly decreased PPGRF and knee extension moment at PPGRF compared with a natural landing duringstop-jump tasks. Attempts to land softly decreased PPGRF compared with a natural landing during side-cutting tasks. Attemptsto land with greater knee flexion at initial ground contact increased knee flexion angle at PPGRF compared witha natural landing during both stop-jump and side-cutting tasks. Attempts to land softly and land with greater knee flexion at initialground contact increased stance time and lower extremity mechanical work, as well as decreased jump height and movementspeed during both stop-jump and side-cutting tasks.Conclusion: Although landing softly and landing with greater knee flexion at initial ground contact may reduce ACL loading duringstop-jump and side-cutting tasks, the performance of these tasks decreased, as indicated by increased stance time and mechanicalwork as well as decreased jump height and movement speed.Clinical Relevance: Training effects tested in laboratory environments with the focus on reducing ACL loading may be reduced inactual competition environments when the focus is on athlete performance. The effects of training programs for ACL injury preventionon lower extremity biomechanics in athletic tasks may need to be evaluated in laboratories as well as in actualcompetitions. [ABSTRACT FROM AUTHOR]

The article discusses a study that determines the impact of knee extension constraint training on lower extremity movement patterns in athletic tasks. Fifty-nine athletes were recruited and screened via a motion analysis test. An image of a knee extension constraint training device instrumented to a knee brace is also shown. It is mentioned that time and sex did not have an interaction impact on the knee flexion angle at the peak impact posterior ground-reaction force.

The article presents a study on the effects of excessive contralateral trunk tilt on pitching biomechanics and performance in high school baseball pitchers. It highlights the hypothesis that this strategy is linked to greater joint loading and poor pitching performance. It mentions the increase in pitching-related upper extremity injuries among young baseball pitchers. Results of the study reveal excessive contralateral trunk tilt is linked to higher ball speeds and increased joint loading.

Javelin throwing is technically demanding. Sequences of upper and lower extremity motions are important for javelin throwing performance. The purpose of this study was to determine the general sequences of upper and lower extremity motions of elite male and female javelin throwers. Three-dimensional kinematic data were collected for 32 female and 30 male elite javelin throwers during competitions. Shoulder, elbow, wrist, hip, knee, ankle, lower trunk, and upper trunk joint and segment angles were reduced for the best trial of each participant. Beginning times of 6 upper extremity and 10 lower extremity joint and segment angular motions were identified. Sequences of the upper and lower extremity motions were determined through statistical analyses. Upper and lower extremity motions of the male and female elite javelin throwers followed specific sequences (P ≤ 0.050). Upper extremity motions of the male and female elite javelin throwers did not follow a proximal-to-distal sequence as suggested in the literature. Male and female elite javelin throwers apparently employed different sequences for upper and lower extremity motions (P < 0.001). Further studies are needed to determine the effects of sequences of upper and lower extremity motions on javelin throwing performance. [ABSTRACT FROM AUTHOR]