Chronic low back pain influences trunk neuromuscular control during unstable sitting among persons with lower-limb loss.

Background: Persons with unilateral lower-limb loss are at increased risk for developing chronic low back pain. Aberrant trunk and pelvis motor behavior secondary to lower-limb loss potentially alters trunk postural control and increases demands on the trunk musculature for stability. However, it is unclear whether trunk postural control is associated with the presence or chronicity of low back pain within this population.

Changes in Trunk and Pelvis Motion Among Persons With Unilateral Lower Limb Loss During the First Year of Ambulation.

Objective: To retrospectively investigate trunk-pelvis kinematic outcomes among persons with unilateral transtibial and transfemoral limb loss with time from initial independent ambulation with a prosthesis, while secondarily describing self-reported presence and intensity of low back pain. Over time, increasing trunk-pelvis range of motion and decreasing trunk-pelvis coordination with increasing presence and/or intensity of low back pain were hypothesized. Additionally, less trunk-pelvis range of motion and more trunk-pelvis coordination for persons with more distal limb loss was hypothesized.

A Comparison of Mental Workload in Individuals with Transtibial and Transfemoral Lower Limb Loss during Dual-Task Walking under Varying Demand.

Objectives: This study aimed to evaluate the influence of lower limb loss (LL) on mental workload by assessing neurocognitive measures in individuals with unilateral transtibial (TT) versus those with transfemoral (TF) LL while dual-task walking under varying cognitive demand.

Methods: Electroencephalography (EEG) was recorded as participants performed a task of varying cognitive demand while being seated or walking (i.e.

Lower Extremity Joint Contributions to Trunk Control During Walking in Persons with Transtibial Amputation.

Controlled trunk motion is crucial for balance and stability during walking. Persons with lower extremity amputation often exhibit abnormal trunk motion, yet underlying mechanisms are not well understood nor have optimal clinical interventions been established. The aim of this work was to characterize associations between altered lower extremity joint moments and altered trunk dynamics in persons with unilateral, transtibial amputation (TTA).

Joint power distribution does not change within the contralateral limb one year after unilateral limb loss.

Background: To assist with forward progression during gait, persons with unilateral lower-limb amputation typically perform more work within the unaffected versus affected limb. However, prior cross-sectional (>2years post-amputation) studies cannot necessarily elucidate the origin or evolution of these compensatory mechanics.

Research Question: Do lower limb joint kinetics change during the initial stages of independent ambulation among persons with lower-limb amputation?

Methods: Nine males with unilateral lower-limb amputation (6 transtibial; 3 transfemoral) completed instrumented gait analyses (speed = 1.

Biomechanical improvements following foot strike biofeedback training for a patient using a passive dynamic ankle-foot orthosis during running.

Background And Purpose: Passive dynamic ankle-foot orthoses have potential to facilitate return to running after a lower limb trauma. However, transitioning patients to new movement patterns that enhance passive dynamic ankle-foot orthoses benefits can pose a challenge. The purpose of this case study was to report biomechanical and functional outcomes for a patient utilizing a passive dynamic ankle-foot orthoses following completion of a session-based, midfoot strike run training program.

Development and validation of a kinematically-driven discrete element model of the patellofemoral joint.

Quantifying the complex loads at the patellofemoral joint (PFJ) is vital to understanding the development of PFJ pain and osteoarthritis. Discrete element analysis (DEA) is a computationally efficient method to estimate cartilage contact stresses with potential application at the PFJ to better understand PFJ mechanics. The current study validated a DEA modeling framework driven by PFJ kinematics to predict experimentally-measured PFJ contact stress distributions.

Trunk muscle forces and spinal loads in persons with unilateral transfemoral amputation during sit-to-stand and stand-to-sit activities.

Background: Alterations and asymmetries in trunk motions during activities of daily living, involving lower extremities, are suggested to cause higher spinal loads in persons with unilateral lower limb amputation. Given the repetitive nature of most activities of daily living, knowledge of the amount of increase in spinal loads is important for designing interventions aimed at prevention of secondary low back pain due to potential fatigue failure of spinal tissues. The objective of this study was to determine differences in trunk muscle forces and spinal loads between persons with and without lower limb amputation when performing sit-to-stand and stand-to-sit tasks.

Do Gait and Functional Parameters Change After Transtibial Amputation Following Attempted Limb Preservation in a Military Population?

Background: Surgical attempts at lower limb preservation after trauma may be complicated by pain and gait disturbances, which can impact the activity level of a military service member. It is unclear how later transtibial amputation (TTA) might affect patients who elect this option after attempts at limb preservation.

Questions/purposes: The purposes of the study were to compare preamputation and postamputation (1) the numeric rating scale for pain and pain medication use; (2) self-reported activity level, Four Square Step Test (FSST) results, and assistive device use; and (3) spatiotemporal variables measured with instrumented gait analysis in individuals who elected TTA after multiple attempts at limb preservation.

The Relationship Between Gait Symmetry and Metabolic Demand in Individuals With Unilateral Transfemoral Amputation: A Preliminary Study.

Introduction: Temporal-spatial symmetry allows for optimal metabolic economy in unimpaired human gait. The gait of individuals with unilateral transfemoral amputation is characterized by temporal-spatial asymmetries and greater metabolic energy expenditure. The objective of this study was to determine whether temporal-spatial asymmetries account for greater metabolic energy expenditure in individuals with unilateral transfemoral amputation.

Biomechanical and neurocognitive performance outcomes of walking with transtibial limb loss while challenged by a concurrent task.

Individuals who have sustained loss of a lower limb may require adaptations in sensorimotor and control systems to effectively utilize a prosthesis, and the interaction of these systems during walking is not clearly understood for this patient population. The aim of this study was to concurrently evaluate temporospatial gait mechanics and cortical dynamics in a population with and without unilateral transtibial limb loss (TT). Utilizing motion capture and electroencephalography, these outcomes were simultaneously collected while participants with and without TT completed a concurrent task of varying difficulty (low- and high-demand) while seated and walking.

Dynamic knee joint stiffness and contralateral knee joint loading during prolonged walking in patients with unilateral knee osteoarthritis.

Background: Long duration walking, a commonly recommended treatment option for knee osteoarthritis (OA), may lead to increased knee joint loading.

Research Question: To evaluate the effects of prolonged walking on dynamic knee joint stiffness and contralateral knee joint contact forces (KCFs) in individuals with unilateral symptomatic knee OA.

Methods: Twenty-six older adults with knee OA completed a 45-minute bout of walking on a treadmill.

A Stimulus-Response Framework to Investigate the Influence of Continuous Versus Interval Walking Exercise on Select Serum Biomarkers in Knee Osteoarthritis.

Objective: The aim of the study was to compare changes in the concentration of serum biomarkers in response to continuous versus interval walking exercise in participants with knee osteoarthritis.

Design: This study used a two-phase sequential design. Twenty-seven participants with unilateral knee osteoarthritis completed two separate treadmill walking sessions: (1) continuous 45-min walking exercise and (2) three 15-min bouts of walking exercise separated by 1-hr rest periods for a total of 45 mins in an interval format.

Associations between trunk postural control in walking and unstable sitting at various levels of task demand.

Trunk postural control (TPC) has been investigated in several populations and tasks. Previous work observed targeted training of TPC via isolated trunk control tasks may improve performance in other activities (e.g.

Knee adduction moment peak and impulse do not change during the first six months of walking with a prosthesis.

Background: Individuals with unilateral lower limb loss are at increased risk for developing knee osteoarthritis in their contralateral limb. The mechanisms underlying this phenomenon are unknown, but large or unusual loads on the limb are thought to contribute to osteoarthritis development. Yet, to our knowledge, there have been no longitudinal assessments of knee joint kinetics to assist with identifying the origin or progression of such loads.

Transfemoral amputee intact limb loading and compensatory gait mechanics during down slope ambulation and the effect of prosthetic knee mechanisms.

Background: Intact limb knee osteoarthritis is a prevalent secondary disability in transfemoral amputees. Walking down a ramp may increase this risk due to excessive limb loading. We sought to determine whether intact limb loading differed between transfemoral amputees and controls during down slope ambulation, and the compensatory strategies transfemoral amputees used to modify intact limb loading.

Trunk muscle activation patterns during walking among persons with lower limb loss: Influences of walking speed.

Persons with lower limb amputation (LLA) walk with altered trunk-pelvic motions. The underlying trunk muscle activation patterns associated with these motions may provide insight into neuromuscular control strategies post LLA and the increased incidence of low back pain (LBP). Eight males with unilateral LLA and ten able-bodied controls (CTR) walked over ground at 1.

Healthy individuals are more maneuverable when walking slower while navigating a virtual obstacle course.

Introduction: Maintaining stability, especially in the mediolateral direction, is important for successful walking. Navigating in the community, however, may require people to reduce stability to make quick lateral transitions, creating a tradeoff between stability and maneuverability. Walking slower can improve stability during steady state walking, but there remains a need to better understand how walking speed influences maneuverability.

Measurement of attentional reserve and mental effort for cognitive workload assessment under various task demands during dual-task walking.

Previous work focused on cognitive workload assessment suggests EEG spectral content and component amplitudes of the event-related potential (ERP) waveform may index mental effort and attentional reserve, respectively. Although few studies have assessed attentional reserve and mental effort during upper-extremity performance, none have employed a combined approach to measure cognitive workload during locomotion. Therefore, by systematically considering ERPs, spectral content and importantly their combination, this study aimed to examine whether concurrent changes in spectral content and ERPs could collectively serve as an index of cognitive workload during locomotion.

Trunk and pelvic dynamics during transient turns among individuals with unilateral traumatic lower limb amputation.

Prior work has identified alterations in trunk-pelvic dynamics with lower limb amputation (LLA) during in-line walking; however, evaluations of other ambulatory tasks are limited. Turns are ubiquitous in daily life but can be challenging for individuals with LLA, prompting additional or unique proximal compensations when changing direction, which over time may lead to development of low back pain. We hypothesized such proximal kinematic differences between persons with and without LLA would exist in the sagittal and frontal planes.

Walking speed differentially alters spinal loads in persons with traumatic lower limb amputation.

Persons with lower limb amputation (LLA) perceive altered motions of the trunk/pelvis during activities of daily living as contributing factors for low back pain. When walking (at a singular speed), larger trunk motions among persons with vs. without LLA are associated with larger spinal loads; however, modulating walking speed is necessary in daily life and thus understanding the influences of walking speed on spinal loads in persons with LLA is of particular interest here.

Modulation of Vertical Ground Reaction Impulse With Real-Time Biofeedback: A Feasibility Study.

Given its apparent representation of cumulative (vs peak) loads, this feasibility study investigates vertical ground reaction impulse (vGRI) as a real-time biofeedback variable for gait training aimed at reducing lower limb loading. Fifteen uninjured participants (mean age = 27 y) completed 12 2-min trials, 1 at each combination of 4 walking speeds (1.0, 1.

Biopsychosocial risk factors associated with chronic low back pain after lower limb amputation.

Low back pain is a common secondary health condition after lower limb amputation with important implications related to functional capabilities and overall quality of life. Despite the high prevalence of low back pain after lower limb amputation, the underlying etiologies of the disorder remain unknown. This hypothesis-driven communication provides evidence in support of using the multifactorial, biopsychosocial model of low back pain experience in the general population for identification of potential risk factors and rehabilitation targets for low back pain after lower limb amputation.

Impact of Traumatic Lower Extremity Injuries Beyond Acute Care: Movement-Based Considerations for Resultant Longer Term Secondary Health Conditions.

Advances in field-based trauma care, surgical techniques, and protective equipment have collectively facilitated the survival of a historically large number of service members (SMs) following combat trauma, although many sustained significant composite tissue injuries to the extremities, including limb loss (LL) and limb salvage (LS). Beyond the acute surgical and rehabilitative efforts that focus primarily on wound care and restoring mobility, traumatic LL and LS are associated with several debilitating longer term secondary health conditions (, low back pain [LBP], osteoarthritis [OA], and cardiovascular disease [CVD]) that can adversely impact physical function and quality of life. Despite recent advancements in prosthetic and orthotic devices, altered movement and mechanical loading patterns have been identified among persons with LL and salvage, which are purported risk factors for the development of longer term secondary musculoskeletal conditions and may limit functional outcomes and/or concomitantly impact cardiovascular health.