CONTEXT Injuries to the anterior cruciate ligament (ACL) occur because of excessive loading on the knee. ACL injury prevention programs can influence sagittal plane ACL loading factors and vertical ground reaction force (VGRF). OBJECTIVE To determine the influence of ACL injury prevention programs on sagittal plane knee biomechanics (anterior tibial shear force, knee flexion angle/moments) an...

background postural instability is one of the common problems of aging. however, with increased age many systems of body such as musculoskeletal system are affected and changed. one of these changes is knee flexion contracture. the study aimed to investigate the simulated knee flexion contracture effects on postural stability in elderly. material and methods 15 elderly subjects (11 men, 4 women...

Appropriate tension of the posterior cruciate ligament, which often is tight in deep flexion, is difficult to achieve after posterior cruciate ligament retaining total knee arthroplasty. Kinematics and maximum flexion after partial release of the posterior cruciate ligament were evaluated in this study. A partial release improved the maximum flexion angle and maintained anteroposterior stabilit...

the resistant* of patesa against lateral displacement (le. the stability), was studied tinder a range of conditions in vitro, at a range of knee flexion angles. muscle forces were applied in physiological directions along the separate quadriceps muscles. normal muscle actions with constant tension showed constant patellar stability up to sixty degrees knee flexion, and then a significant increa...

conclusions an increased lumbar lordosis during the prone knee-flexion test is due to instability in a lumbar spine region. results results demonstrated that there was a statistically significant difference in lumbar lordosis in prone position and after performing the prone knee-flexion test among healthy subjects (p < 0.0001). patients and methods this quasi-experimental study with repeated me...

BACKGROUND Previous experimental studies have been conducted to evaluate the biomechanical effects of posterior cruciate ligament reconstruction; but no consensus has been reached on the preferred method of reconstruction. METHODS The 3D finite element mesh of a knee joint was reconstructed from computed tomography and magnetic resonance images. The ligaments were considered as hyperelastic m...

CONTEXT Researchers have suggested that large landing forces, excessive quadriceps activity, and an erect posture during landing are risk factors for anterior cruciate ligament (ACL) injury. The influence of knee kinematics on these risk factors has been investigated extensively, but trunk positioning has received little attention. OBJECTIVE To determine the effect of trunk flexion on landing...

CONTEXT Sex differences in lower extremity landing mechanics and muscle activation have been identified as potential causative factors leading to the increased incidence of anterior cruciate ligament injuries in female athletes. Valgus knee alignment places greater strain on the anterior cruciate ligament than a more neutral alignment. Gluteus medius (GM) activation may stabilize the leg and pe...

The interactive effects of neuro-developmental treatment and inhibitive ankle-height orthoses on gait were examined via a single-subject research design. Knee flexion during gait at initial contact, mid-stance, heel-off, and mid-swing were measured in a 2-year-old girl with diplegia by use of a goniometer and freeze-frame videography. During the treatment and treatment/orthoses phases, a decrea...

Crouch gait, a troublesome movement abnormality among persons with cerebral palsy, is characterized by excessive flexion of the hips and knees during stance. Treatment of crouch gait is challenging, at present, because the factors that contribute to hip and knee extension during normal gait are not well understood, and because the potential of individual muscles to produce flexion or extension ...