|Absolute Serum Hormone Levels Predict the Magnitude of Change in Anterior Knee Laxity across the Menstrual Cycle
||This study aimed to determine whether absolute sex hormone concentrations predict the magnitude of knee joint laxity changes across the menstrual cycle. Twenty-two females (18–30 years, body mass index =30), who reported normal menstrual cycles for t...
|ACL Injuries: The Gender Bias
Ground Reaction Forces, but Not Knee Muscle Activation, or Sagittal Knee Joint Stiffness Differ Between Female Dancers and Basketball Players during Drop Jumps
Influence of Ankle Dorsiflexion Range of Motion and Lower Leg M...
|Anterior Cruciate Ligament Injury in Collegiate Female Dancers
||ABOUT 80,000 to 250,000 anterior cruciate
ligament (ACL) injuries of the knee occur
annually, with many of these injuries affecting
individuals between the ages of 15-25
years.1 The majority of ACL injuries are noncontact
|Assessment of neuromuscular response characteristics at the knee following a functional perturbation
||Previous research indicates that both the extent and timing of muscular activation at the knee can be influenced by muscle activity state, joint angle, weight-bearing status and trunk position. However, little research to date has evaluated protectiv...
|Collagen Gene Variants Previously Associated With Anterior Cruciate Ligament Injury Risk Are Also Associated With Joint Laxity
||Background: Genetic association studies demonstrate a relationship between several collagen gene variants and anterior cruciate ligament (ACL) injury, yet the mechanism of these relationships is still unclear. Joint laxity is a heritable trait; incre...
|A Comparison of Cyclic Variations in Anterior Knee Laxity, Genu Recurvatum, and General Joint Laxity across the Menstrual Cycle
||Changes in anterior knee laxity (AKL), genu recurvatum (GR) and general joint laxity (GJL) were quantified across days of the early follicular and early luteal phases of the menstrual cycle in 66 females, and the similarity in their pattern of cyclic...
|Cyclic variations in multiplanar knee laxity influence landing biomechanics.
||Purpose: Females vary substantially in their multiplanar cyclic knee laxity changes across the menstrual cycle. The biomechanical implications of these cyclic changes are relatively unknown. Our purpose was to first cluster females based on their cyc...
|Dynamic Valgus Alignment and Functional Strength in Males and Females During Maturation
||Context: Sex differences in dynamic measures have been established in physically mature populations. Gaining information on maturation's effect on dynamic performance measures implicated in injury risk may enable us to better design injury prevention...
|Effect of axial load on anterior tibial translation when transitioning from non-weight bearing to weight bearing
While the application of compressive joint loads and thigh muscle activity are associated with anterior tibial translation in vitro, less is known during early load acceptance in vivo. We investigated the effects of increasing axial loads...
|Effect of coupling medium temperature on rate of intra-muscular temperature rise using continuous ultrasound
||Objective: We determined the effects of coupling medium temperature on the rate of intramuscular temperature rise (RTR) during continuous ultrasound.
Design and Setting: Ultrasound was applied in a continuous mode at a frequency of 1 MHz and intensi...
|Effects of Transverse and Frontal Plane Knee Laxity on Hip and Knee Neuromechanics During Drop Landings
||Background Varus-valgus (LAXVV) and internal-external (LAXIER) rotational knee laxity have received attention as potential contributing factors in anterior cruciate ligament injury. This study compared persons with above-and bel...
|Energy absorption as a predictor of leg impedance in highly trained females
||Although leg spring stiffness represents active muscular recruitment of the lower extremity during dynamic tasks such as hopping and running, the joint-specific characteristics comprising the damping portion of this measure, leg impedance, are uncert...
|Females recruit quadriceps faster than males at multiple knee flexion angles following a weight-bearing rotary perturbation
||Objective: To compare the effect of knee angle on muscle response times and neuromuscular recruitment patterns between sexes following a perturbation in single leg stance at 10°, 20°, and 30°. We hypothesized that response times would be faster at le...
|The independent and interactive effects of navicular drop and quadriceps angle on neuromuscular responses to a weight bearing perturbation
||Little is known about the effects of static alignment on neuromuscular control of the knee during dynamic motion. To evaluate the isolated and combined effects of quadriceps angle (QA) and navicular drop (ND) on neuromuscular responses to a weight-be...
|Joint Laxity Is Related to Lower Extremity Energetics during a Drop Jump Landing
||Purpose: To examine the relationships between anterior knee laxity (AKL), genu recurvatum (GR), and general joint laxity (GJL) with sagittal plane energetics in males and females during a drop jump task. Methods: A total of 68 females and 50 males we...
|Kinematic analysis of functional lower extremity perturbations
||Background. Sudden changes in direction on a single weight-bearing-limb are commonly associated with injury to the lower extremity. The purposes of this study were to assess the between day reliability of hip, knee, and ankle kinematic displacements ...
|Knee joint laxity affects muscle activation patterns in the healthy knee
||This study investigated the effects of anterior knee joint laxity on muscle activation patterns prior to and following a lower extremity perturbation. Participants were subjected to a forward and either internal (IR) or external (ER) rotation perturb...
|Knee Joint Laxity and Its Cyclic Variation Influence Tibiofemoral Motion during Weight Acceptance
||Purpose - To better understand how sex differences in anterior knee joint laxity (AKL) impact knee joint biomechanics, we examined the consequence of greater absolute baseline (males and females) and cyclic increases in AKL during the menstrual cycle...
|Knee ligament behavior following a controlled loading protocol does not differ by menstrual cycle day
||Background. Females experience a disproportionate number of anterior cruciate ligament injuries compared to males. Increased estradiol concentration has been suggested to alter ligament properties and strength. Determining whether the knee responds d...
|Low levels of anterior tibial loading enhance knee extensor reflex response characteristics
||We examined whether neuromuscular reflexes were altered with anterior loads applied to the tibiofemoral joint. A ligament testing device was modified by attaching a reflex hammer to a steel mounted frame to illicit a patellar tendon tap, while anteri...
|Neuromuscular Response Characteristics in Men and Women After Knee Perturbation in a Single-Leg, Weight-Bearing Stance.
||Objective: We examined whether muscle response times and activation patterns in the lower extremity differed between men and women in response to a rotational knee perturbation while standing in a single-leg, weight-bearing stance.
Design and Settin...
|Physical rehabilitation and the challenge of anterior cruciate ligament injury in the physically active female
||Rehabilitation professionals facilitate healthy movement and mobility in individuals seeking to engage in physically active lifestyles. The disparate rate of injury to the anterior cruciate ligament of the knee in physically active females in compari...
|Relationship between sex hormones and anterior knee laxity across the menstrual cycle
||Purpose: To comprehensively quantify through daily, serial measures changes in knee laxity as a function of changing sex-hormone levels across one complete menstrual cycle.
Methods: Twenty-five females, 18–30 yr, body mass index <= 30, who reported ...
|Relationships Between Lower Extremity Alignment and the Quadriceps Angle
||Objective: To determine the extent to which select lower extremity alignment characteristics of the pelvis, hip, knee, and foot are related to the Q angle.
Design: Descriptive cohort study design.
Setting: Applied Neuromechanics Research L...
|The Reliability and Validity of Ankle Inversion and Eversion Torque Measurements From the Kin Com II Isokinetic Dynamometer
||This study examined the test—retest reliability of a prototype device used to measure ankle inversion and eversion isokinetic average torque values. The purpose of this paper was to illustrate a situation where common isokinetic measures were reliabl...
|Reliability and validity of the Biodex System 3 Pro Isokinetic Dynamometer velocity, torque and position measurements
||This study quantitatively assessed the mechanical reliability and validity of position, torque and velocity measurements of the Biodex System 3 isokinetic dynamometer. Trial-to-trial and day-to-day reliability were assessed during three trials on two...
|Serial administration of clinical concussion assessments and learning effects in healthy young athletes
||Objective: To determine if serial administration of the Standardized Assessment of Concussion (SAC) and Balance Error Scoring System (BESS) would elicit a learning effect in young athletes and to determine the intratester reliability of scoring the B...
|Sex Differences in Coupled Knee Motions during the Transition from Non-Weight Bearing to Weight Bearing
||Knee ligament injuries frequently happen when the joint transitions from non-weight bearing (NWB) to weight bearing (WB). To gain insight into the mechanism that produces these injuries, physically active females (N = 41) and males (N = 39) underwent...
|Sex differences in lower extremity biomechanics during single leg landings
||Background. Females have an increased incident rate of anterior cruciate ligament tears compared to males. Biomechanical strategies to decelerate the body in the vertical direction have been implicated as a contributing cause. This study determined i...
|Sex specific abdominal activation strategies during landing
||Control of the trunk segment in landing has been implicated as a contributing factor to the higher incidence of anterior cruciate ligament injuries in females than in males. Investigating the sex-specific abdominal activation strategies during landin...
|Some Sex Hormone Profiles are Consistent over Time in Normal Menstruating Women: Implications for Sports Injury Epidemiology
||Purpose-It is unclear whether sex hormone profiles obtained in two consecutive months are consistent within women. Month-to-month consistency in daily, nadir, peak and mean hormone concentrations during the early follicular and luteal phases in recre...
|Thigh Strength and Activation as Predictors of Knee Biomechanics during a Drop Jump Task
||Purpose: To examine whether normalized quadriceps and hamstring strength would predict quadriceps and hamstring muscle activation amplitudes and whether these neuromuscular factors would predict knee kinematics and kinetics during a drop jump task. M...
|Using Surface Electromyography To Assess Sex Differences in Neuromuscular Response Characteristics
||Objective: To provide an overview of the continuum of muscular responses that typically occur with joint perturbation. The applications and limitations of surface electromyography (sEMG) in evaluating these responses are also addressed. Research appl...
|Variations in Varus/Valgus and Internal/External Rotational Knee Laxity and Stiffness Across the Menstrual Cycle
||Cyclic variations in genu recurvatum (GR), general joint laxity (GJL), varus–valgus (VV), and internal–external (IER) rotational laxities and stiffnesses were examined in 64 females and 43 males at two time points during the females' menstrual cycle ...