Concurrent Force Feedback on Load Symmetry in Total Knee Arthroplasty Patients.

Background And Purpose: Load asymmetry can be present before and after total knee arthroplasty (TKA), which may affect progress during knee rehabilitation in an outpatient sports medicine setting. Current rehabilitation primarily focuses on strength, pain, and range of motion deficits; however, recent evidence suggests the use of movement retraining strategies such as load feedback to address load asymmetry. Therefore, the purpose of this study was to examine how a single session of concurrent force feedback influences load symmetry during the leg-press and body-weight squat exercises in individuals following TKA.

Dynamic postural control in injured collegiate cross-country runners is not associated with running-related injury.

Background: Biomechanical factors have been associated with running-related injury, but associations are unclear. Dynamic postural stability may be a factor related to injury that has not been studied extensively.

Research Question: Does dynamic postural control differ in those with a history of running-related injury or those who go on to sustain a running-related injury?

Methods: Sixty-five (45 injured; 20 uninjured) and fifty-eight (13 injured; 45 uninjured) collegiate cross-country runners were available for our retrospective and prospective analyses.

Effects of Body Weight Support in Running on Achilles Tendon Loading.

Achilles tendon (AT) tendinopathy is common in runners. Repetitive AT loading may play a role in etiology. Interventions such as body weight support (BWS) may reduce loading on the AT in running.

Alterations in Achilles tendon stress and strain across a range of running velocities.

Running has a high incidence of overuse injuries. Achilles tendon (AT) injuries may occur due to high forces and repetitive loading during running. Foot strike pattern and cadence have been linked to the magnitude of AT loading.

Kinematic and muscle force asymmetry in healthy runners: How do different methods measure up?

Background: Comparing the performance of one leg to another is a common means of assessing running gait to help inform clinical management strategies. Various methods are employed to quantify asymmetries between limbs. However, limited data is available describing the amount of asymmetry that may be expected during running and no index has been identified as preferable for making a clinical determination of asymmetry.

Added mass increases Achilles tendon stress in female runners.

Context: Achilles tendon (AT) injuries are common in female runners and military personnel where increased AT loading may be a contributing factor. Few studies have examined AT stress during running with added mass. The purpose was to examine the stress, strain, and force placed on the AT, kinematics and temporospatial variable in running with different amounts of added mass.

An Updated Model Does Not Reveal Sex Differences in Patellofemoral Joint Stress during Running.

Background: Structure-specific loading may have implications in understanding the mechanisms of running related injury. As females demonstrate a prevalence of patellofemoral pain twice that of males, this may indicate differences in patellofemoral loads between males and females. Previous works investigating differences in patellofemoral joint stress have shown conflicting results, but the models employed have not used estimates of muscle forces or sex specific contact areas.

Transfer of post-trial feedback on impacts during drop landings in female athletes.

Increased vertical ground reaction force (vGRF) and dynamic knee valgus contribute to non-contact anterior cruciate ligament (ACL) injuries. We examined feedback's influence during landing and transfer to a game-specific drill, measured by deceleration. Thirty-one female athletes performed 30 drop landings with augmented feedback and dual-task conditions, with a game-specific drill before and after.

Offloading Effects on Impact Forces and Patellofemoral Joint Loading During Running in Females.

Background: Structure-specific loading is being increasingly recognized as playing a role in running related injuries. The use of interventions targeted at reducing patellofemoral joint loads have shown effectiveness in reducing symptoms of patellofemoral pain. Use of bodyweight support (BWS) has the potential to reduce loading on the patellofemoral joint during running to augment rehabilitation efforts.

Anabolic Bone Stimulus Requires a Pre-Exercise Meal and 45-Minute Walking Impulse of Suprathreshold Speed-Enhanced Momentum to Prevent or Mitigate Postmenopausal Osteoporosis within Circadian Constraints.

Osteoporosis currently afflicts 8 million postmenopausal women in the US, increasing the risk of bone fractures and morbidity, and reducing overall quality of life. We sought to define moderate exercise protocols that can prevent postmenopausal osteoporosis. Our previous findings singled out higher walking speed and pre-exercise meals as necessary for suppression of bone resorption and increasing of markers of bone formation.

Kinetic changes associated with extended knee landings following anterior cruciate ligament reconstruction in females.

Objectives: To determine the relationship between knee flexion excursion symmetry and lower extremity kinematics, kinetics, and muscle, joint, and ligament forces in females 1-3 years after ACL reconstruction.

Design: Cross-sectional.

Setting: Laboratory.

Changes in landing mechanics using augmented feedback: 4-Week training and retention study.

Context: Non-contact ACL injuries are common in female athletes during landing tasks. Post-trial performance-based feedback may be an effective method to reduce landing forces and knee valgus during landing. Information regarding the retention of these changes based on such training is generally lacking for weekly and monthly retention.

Effect of Increasing Running Cadence on Peak Impact Force in an Outdoor Environment.

Background: An estimated 56% of recreational runners sustain a running-related injury related to the high impact forces in running. Increasing step frequency (cadence) while maintaining a consistent speed has been shown to be an effective way to lower impact forces which may reduce injury risk.

Purpose: To examine effects of increased cadence on peak impact force during running in an outdoor setting.

The effects of incremental changes in rucksack load on lower extremity joint Kinetic patterns during ruck marching.

Injuries are often attributed to ruck marching. Therefore, it is important to examine how load carriage influences gait mechanics. The purpose of this study was to examine how subtle changes in rucksack load influence joint torque patterns during marching.

Normative Measures of Hip Strength and Relation to Previous Injury in Collegiate Cross-Country Runners.

Context: Running-related injury occurs frequently in collegiate cross-country runners. Hip strength is one factor that may be important in the rehabilitation and training of cross-country runners. However, no normative values exist to inform these strategies.

THE INFLUENCE OF VISUAL FIXATION ON HOP TEST PERFORMANCE.

Background: It has been recognized that anterior cruciate ligament (ACL) injuries typically occur when athletes are attending to a secondary task or object, including teammates, opponents, and/or a goal. Commonly applied tests after ACL injury include a series of hop tests to determine functional status, yet do not control for visual fixation.

Purpose: To examine the influence of visual fixation during two functional hop tests in healthy individuals.

Patellofemoral joint loading during the forward and backward lunge.

Objective: To examine patellofemoral joint (PFJ) loading in two lunge movements: Forward Lunge (FL) and Backward Lunge (BL).

Design: Repeated Measures.

Setting: University Biomechanics Laboratory.

Effect of Hamstring-to-quadriceps Ratio on Knee Forces in Females During Landing.

ACL injuries in the athletic population are a common occurrence with over 70% associated with non-contact mechanisms. The hamstring to quadriceps ratio is a widely used clinical measure to assess an athlete's readiness to return to sport; however, its relationship to knee forces and ACL tension during landing is unknown. Baseline isokinetic testing was completed on 100 college-aged females.

The influence of center line width during the crossover hop test.

Objectives: To assess the influence of center line width on crossover hop for distance test (XHOP) performance.

Design: Repeated measures.

Setting: University laboratory.

Relationship among maximum hip isometric strength, hip kinematics, and peak gluteal muscle force during running.

Objective: To determine if there is a relationship among isometric hip strength, hip kinematics, and peak gluteal muscle forces in cross-country runners during running.

Design: Cross Sectional.

Setting: University Biomechanics Laboratory.

Two-dimensional versus three-dimensional measurement of infant cervical active motion.

Introduction: Upright infant active cervical motion (ACM) is difficult to measure accurately by a single examiner. Clinically, physical therapists use visual estimation, which has limited reliability and concurrent validity with gold standards. Consistent, reliable, and valid active motion measurements are needed to document infant status and response to intervention.

INCORPORATING A DUAL-TASK ASSESSMENT PROTOCOL WITH FUNCTIONAL HOP TESTING.

Background: Hop tests are commonly used within a testing battery to assess readiness for return to sport after anterior cruciate ligament (ACL) injury, yet athletes still experience a high rate of re-injury. Simultaneous performance of a secondary task requiring cognitive processing or decision-making may test the athlete under more realistic contexts.

Purpose: To examine a clinically feasible, dual-task assessment paradigm applied during functional hop tests in healthy individuals.

Real-time visual feedback reduces patellofemoral joint forces during squatting in individuals with patellofemoral pain.

Background: Elevated patellofemoral joint forces appear to contribute to the development of patellofemoral pain. As a result, treatment of patellofemoral pain often includes movement retraining intended to reduce patellofemoral joint forces. Real-time visual feedback has been shown to be effective for retraining running kinematics; however, we are not aware of a previous study that has examined the influence of real-time visual feedback on patellofemoral joint mechanics during a squat.