Approximately 320,000 anterior cruciate ligament (ACL) injuries in the United States each year are non-contact injuries, with many occurring during a single-leg jump landing. To reduce ACL injury risk, one option is to improve muscle strength and/or the activation of muscles crossing the knee under elevated external loading. This study's purpose was to characterize the relative force production...

CONTEXT Coactivation ratio of quadriceps to hamstring muscles (Q:H) and medial to lateral knee muscles (M:L) contributes to the dynamic stability of the knee joint during movement patterns recommended during rehabilitation and important for daily function. OBJECTIVE To compare the quadriceps-to-hamstring and medial-to-lateral knee muscles' coactivation ratios between men and women during the ...

„The objective of this study was to investigate the action of the muscles at the hip and knee joints, with a view to identify those muscles which play a major role in sprinting. Taking, as their hypothesis, that the velocity of a sprinter, running at full speed, is directly related to the velocity of the swing back of the legs a movement started from the high point of the knee lift down to foot...

We investigated gender differences in hamstring reflex responses and posterior-anterior tibial translation (TT) before and after fatiguing exercise. We assessed the isolated movement of the tibia relative to the femur in the sagittal plane as a consequence of mechanically induced TT in standing subjects. The muscle activity of the hamstrings was evaluated. After fatigue, reflex onset latencies ...

STUDY DESIGN Controlled laboratory study. OBJECTIVES To quantify phase duration and lower extremity muscle activation and alignment during the most common types of soccer kick-the instep kick and side-foot kick. A second purpose was to test the hypotheses that different patterns of lower extremity muscle activation occur between the 2 types of kicks and between the kicking limb compared to th...

A musculoskeletal model was developed to analyze the tensions of knee joint ligaments during walking and understand how they change with changes in muscle forces. The included femur, tibia, patella all components cruciate collateral ligaments, quadriceps, hamstrings gastrocnemius muscles. Inputs were forces, estimated by a static optimization approach, external loads (ground reaction forces mom...

PURPOSE An anterior cruciate ligament (ACL) injury involves a multi-planar injury mechanism. Nevertheless, unexpected multi-planar perturbations have not been used to screen athletes in the context of ACL injury prevention yet could reveal those more at risk. The objective of this study was to compare neuromuscular responses to multi-planar (MPP) and single-planar perturbations (SPP) during a s...