Detection of Acute and Long-Term Effects of Concussion: Dual-Task Gait Balance Control Versus Computerized Neurocognitive Test.

Objective: To examine the acute (within 72h of injury) and long-term (2mo postinjury) independent associations between objective dual-task gait balance and neurocognitive measurements among adolescents and young adults with a concussion and matched controls.

Design: Longitudinal case-control.

Setting: Motion analysis laboratory.

Sex-Specific Relationships Between Hip Strength and Hip, Pelvis, and Trunk Kinematics in Healthy Runners.

Weak hip muscle strength and excessive hip motion during running have been suggested as potential risk factors for developing patellofemoral pain syndrome (PFPS) in females, but not males. There is conflicting evidence on the relationship between hip strength and hip kinematics, which may be partly due to sex differences in the relationship between these parameters. Hip, pelvis, and trunk kinematics were collected while 60 healthy, habitual runners (23 females, 37 males) ran overground, and isometric hip abduction and external rotation strengths were measured bilaterally.

Single-task and dual-task tandem gait test performance after concussion.

Objectives: To compare single-task and dual-task tandem gait test performance between athletes after concussion with controls on observer-timed, spatio-temporal, and center-of-mass (COM) balance control measurements.

Design: Ten participants (19.0±5.

Consistency and cost of dual-task gait balance measure in healthy adolescents and young adults.

Matched control data are commonly used to examine recovery from concussion. Limited data exist, however, examining dual-task gait data consistency collected over time in healthy individuals. The study purposes were to: 1) assess the consistency of single-task and dual-task gait balance control measures, 2) determine the minimal detectable change (MDC) of gait balance control measures, and 3) examine the extent to which age and task complexity affect dual-task walking costs in healthy adolescents and young adults.

Return to Physical Activity Timing and Dual-Task Gait Stability Are Associated 2 Months Following Concussion.

Objective: The effect of physical activity resumption on functional recovery following concussion is poorly understood. We sought to examine the relationship between physical activity resumption timing and gait stability 2 months following concussion.

Setting: Motion analysis laboratory.

Adolescents demonstrate greater gait balance control deficits after concussion than young adults.

Background: Age has been described as a factor that affects recovery after concussion. The recommended management protocol is to treat adolescents in a more cautious manner than adults. However, few studies have prospectively and longitudinally assessed the way these age groups perform on motor tasks after concussion.

Return to activity after concussion affects dual-task gait balance control recovery.

Background: Recent work has identified deficits in dual-task gait balance control for up to 2 months after adolescent concussion; however, how resumption of preinjury physical activities affects recovery is unknown.

Purpose: The objective of this study is to examine how return to activity (RTA) affects recovery from concussion on measures of symptom severity, cognition, and balance control during single-task and dual-task walking.

Methods: Nineteen adolescents with concussion who returned to preinjury activity within 2 months after injury and 19 uninjured, matched controls completed symptom inventories, computerized cognitive testing, and single-task and dual-task gait analyses.

Center of pressure trajectory differences between shod and barefoot running.

This study examined differences in center of pressure (COP) trajectories between shod and barefoot running. Ten habitually shod runners ran continuous laps under both shod and barefoot conditions. The COP trajectory was calculated in the global coordinate system but then transformed to the anatomic coordinate system of the foot.

The effect of cognitive task complexity on gait stability in adolescents following concussion.

Concussion has been reported to result in disturbances to motor and cognitive functions. One way to examine these disturbances is through a dual-task assessment. Many secondary cognitive tasks have been proposed as appropriate tools during concussion assessment; however, task complexity has not been compared within a dual-task investigation.

Dual-task effect on gait balance control in adolescents with concussion.

Objective: To prospectively and longitudinally examine how concussion affects gait balance control in adolescents during single- and dual-task walking.

Design: Cohort, prospective, repeated-measures design.

Setting: Motion analysis laboratory.

Torsion deformity and joint loading for medial knee osteoarthritis.

Purpose: The consequences of lower limb torsion deformity on knee loading in knee osteoarthritis are poorly understood. The purpose of this study was to quantify the associations between the mechanical axis, tibial torsion and knee loading in subjects with medial knee OA and in controls.

Methods: Twenty-four subjects: end-staged medial knee osteoarthritis (OA) with apparent torsion deformity (TKO, n=6) and without torsion deformity (KOA, n=8) and controls (CON, n=10) were imaged using long standing lower extremity (LSLE) radiographs and computed tomography (CT).

A multivariate statistical ranking of clinical and gait measures before and after total knee replacement.

The purpose of this study was to assess the use of a multivariate statistical method to rank clinical and gait variables, thus describing a ranking of patient dysfunction prior to and following total knee replacement (TKR) surgery. Twenty end-stage knee osteoarthritis (KOA) subjects scheduled for TKR and 20 healthy controls performed level walking and stair ascent twice: pre- (P1) and 6 months post-surgery (P2). Clinical and gait measures were entered into a principle component analysis (PCA) to determine orthogonal principle components (PCs).

The effect of total knee replacement on the knee varus angle and moment during walking and stair ascent.

Background: This study examined the effect of total knee replacement surgery on the frontal plane knee varus angle and moment. Secondarily, the relationships between knee varus angle and moment to a clinical outcome measure were assessed.

Methods: Twenty-one patients with total knee replacement and 21 controls performed level walking and stair ascent at two testing periods, pre- and 6-months post-surgery.

Balance control during gait in athletes and non-athletes following concussion.

Current literature provides only limited information regarding performance on dynamic motor tasks following concussion. However, recent investigations have suggested that participation in contact sports may have a negative effect on cognitive function without the existence of a medically diagnosed concussion. The purpose of this study was to examine balance control during gait in concussed and uninjured athletes and non-athletes.

Shoulder joint position sense improves with external load.

Joint position sense (JPS) is important in the maintenance of optimal movement coordination of limb segments in functional activities. Researchers have shown that the sensitivity of musculotendinous mechanoreceptors increases as muscle activation levels increase. In the present study, when 25 participants tried to replicate the same presented position, both vector and elevation angle repositioning errors decreased linearly as the external load increased up to 40% above unloaded shoulder torque.

The effect of total knee replacement on dynamic support of the body during walking and stair ascent.

Background: Little is known about the effects of total knee replacement surgery on the contributions of individual joint moments to the total support moment. A better understanding of these effects may enhance rehabilitation protocols and determine factors related to long-term surgical outcome.

Method: Twenty-one subjects with total knee replacement and 21 controls performed level walking and stair ascent at two testing periods, pre- and 6 months post-surgery.

Recovery of cognitive and dynamic motor function following concussion.

Objective: Neuropsychological testing has been advocated as an important tool of proper post-concussion management. Although these measures provide information that can be used in the decision of when to return an individual to previous levels of physical activity, they provide little data on motor performance following injury. The purpose of this investigation was to examine the relationship between measures of dynamic motor performance and neuropsychological function following concussion over the course of 28 days.

The effect of total knee replacement surgery on gait stability.

The purpose of this study was to investigate the effect of knee pain and total knee replacement (TKR) surgery on the gait stability of knee osteoarthritis (OA) patients compared to controls. Gait spatio-temporal measures, center of mass kinematics and pain levels of 21 TKR subjects and 21 controls (CON) were assessed during level walking and obstacle crossing at two testing periods, pre-surgery (P1) and 6 months post-surgery (P2). The TKR patients reported greater pain and disability than CONs at P1 and P2, walked and negotiated the obstacle more slowly and had a shorter stride length than CONs.

Attentional disengagement dysfunction following mTBI assessed with the gap saccade task.

Concussion, or mild traumatic brain injury (mTBI), leads to a number of cognitive, attentional, and sensorimotor deficits that can last a surprisingly long time after the initial injury. We have previously shown that the ability to orient visuospatial attention is deficient in participants with mTBI within 2 days of their injury, but then recovers to normal levels within a week. Orienting attention requires disengagement from the point of fixation, movement of attention to the location of interest, and re-engagement at that location.

Cancelling planned actions following mild traumatic brain injury.

Mild traumatic brain injury (mTBI) leads to a variety of attentional, cognitive, and sensorimotor deficits. An important aspect of behavior that intersects each of these functions is the ability to cancel a planned action. Thus, the purpose of this study was to determine the effects of mTBI on the ability to perform a countermanding saccade task.

Gait stability following concussion.

Introduction: The need to identify functional impairment following a brain injury is critical to prevent reinjury during the period of recovery. However, little is known about the effect of concussion on dynamic motor function.

Purpose: The purpose of this study was to examine the effect of concussion on a dynamic motor task under conditions of divided and undivided attention over the course of 28 d.

Shoulder joint position sense improves with elevation angle in a novel, unconstrained task.

Proprioception, encompassing the submodalities of kinesthesia and joint position sense, is important in the maintenance of joint stability, especially in the shoulder. The purpose of this study was to examine the effects of plane and elevation angle on unconstrained shoulder joint position sense. Twenty-two subjects (12 male, 10 female) without a history of shoulder pathology were recruited from a university campus.

Tracking the recovery of visuospatial attention deficits in mild traumatic brain injury.

The goal of the current investigation was to probe the deficits in the alerting, orienting and executive components of visuospatial attention in individuals who have recently suffered a mild traumatic brain injury (mTBI) and to assess the rate and degree of recovery for each of these components over a month post-injury. A group design was employed to assess and compare the performance of participants (12 males, 8 females; mean age: 21 +/- 1.74 years) identified with mTBI relative to control subjects matched for gender, age, height, weight and activity level.

The effect of divided attention on gait stability following concussion.

Background: The need to identify functional impairment following a brain injury is critical to prevent re-injury during the period of recovery. While many neuropsychological tests have been developed to assess cognitive performance, relatively little information on gait and dynamic stability is available on motor task performance for young adults following concussion. This study was performed to investigate the effect of divided attention following concussion on various gait variables.

Bilateral accommodations to anterior cruciate ligament deficiency and surgery.

Unlabelled: OBJECTIVE To determine bilateral lower extremity joint accommodations during gait in anterior cruciate ligament deficient subjects and uninjured controls.

Design: Gait testing of 10 chronic anterior cruciate ligament deficient subjects prior to and 3 months following reconstructive surgery, and 10 uninjured controls.

Background: It is possible that bilateral joint accommodations could occur as a result of anterior cruciate ligament injury and in response to surgical repair.