Association of Low Physical Activity Levels With Gait Patterns Considered at Risk for Clinical Knee Osteoarthritis Progression.

Objective: Although gait analysis provides an estimate of joint loading magnitude and patterns during a typical step, accelerometry provides information about loading frequency. Understanding the relationships between these components of loading and knee osteoarthritis (OA) progression may improve conservative management, as gait interventions may need to account for physical activity levels or vice versa. The primary objective was to examine relationships between gait patterns that have previously been associated with OA progression and accelerometer-derived metrics of loading frequency.

Association Between Knee Joint Muscle Activation and Knee Joint Moment Patterns During Walking in Moderate Medial Compartment Knee Osteoarthritis: Implications for Secondary Prevention.

Objective: To determine associations between knee moment features linked to osteoarthritis (OA) progression, gait muscle activation patterns, and strength.

Design: Cross-sectional secondary analysis.

Setting: Gait laboratory.

Quantifying Achievable Levels of Improvement in Knee Joint Biomechanics During Gait After Total Knee Arthroplasty Relative to Osteoarthritis Severity.

Total knee arthroplasty (TKA) surgery improves knee joint kinematics and kinetics during gait for most patients, but a lack of evidence exists for the level and incidence of improvement that is achieved. The objective of this study was to quantify patient-specific improvements in knee biomechanics relative to osteoarthritis (OA) severity levels. Seventy-two patients underwent 3-dimensional (3D) gait analysis before and 1 year after TKA surgery, as well as 72 asymptomatic adults and 72 with moderate knee OA.

Trunk Muscle Activation Patterns Differ Between Those With Low and High Back Extensor Strength During a Controlled Dynamic Task.

It is proposed that reduced function in one of the spinal systems (active, passive, and neural) outlined by Panjabi could increase the risk of experiencing a low back injury (LBI). Also proposed is that reduced function in any one system can be compensated for by adjusting the time-varying recruitment of trunk muscles. This study addressed whether those with reduced active system function (WEAK), measured as back extensor strength, would have different trunk muscle activation patterns than those with higher function (STRONG), and secondly whether this relationship would be modified following recovery from a LBI.

Baseline Gait Muscle Activation Patterns Differ for Osteoarthritis Patients Who Undergo Total Knee Arthroplasty Five to Eight Years Later From Those Who Do Not.

Objective: To determine if baseline quadriceps and hamstrings muscle activity patterns differed between those with medial-compartment knee osteoarthritis (OA) who advanced to total knee arthroplasty (TKA) and those who did not advance to TKA, and to examine associations between features extracted from principal component analysis (PCA) and discrete measures.

Methods: Surface electromyograms of the vastus lateralis and medialis, rectus femoris, and lateral and medial hamstrings during walking were collected from 54 individuals with knee OA. Amplitude and temporal characteristics from PCA, co-contraction indices (CCI) for lateral and medial muscle pairs, and root mean square (RMS) amplitudes for early, mid, late, and overall stance were calculated from electromyographic waveforms.

Longitudinal evidence links joint level mechanics and muscle activation patterns to 3-year medial joint space narrowing.

Background: It is currently not known if there are different mechanical factors involved in accelerated rates of knee osteoarthritis structural progression. Data regarding the role of the transverse plane moment along with the contributions to joint loading from muscle activity, a primary contributor to the joint loading environment, is not well represented in the current literature on knee OA radiographic progression. The objective of this study was to understand if a 3-year end point corroborates what has been shown for longer term radiographic progression or provides more insight into factors that may be implicated in more accelerated radiographic progression than those shown previously.

Do Older Adults and Those Recovered from Low Back Injury Share Common Muscle Activation Adaptations?

Theoretical models suggest trunk muscle activation compensates for spinal systems impairments. The purpose of this study was to determine if two populations (older adults and those recovered from a lower back injury (rLBI)) with spinal system impairments have similar muscle activation patterns to each other, but differ from controls. Trunk electromyograms collected from 12 older adults, 16 rLBI, and 19 controls during two dynamic tasks showed that older adults and rLBI had higher activation amplitudes, sustained temporal and more synergistic activation relative to controls.

Asymptomatic and symptomatic individuals with the same radiographic evidence of knee osteoarthritis walk with different knee moments and muscle activity.

There is an established discordance between the structural joint damage and clinical symptoms of knee osteoarthritis; however, there has been little investigation into the differences in joint level biomechanics and muscle activation patterns during gait between symptomatic and asymptomatic individuals with the same radiographic evidence of osteoarthritis. The objective of this study was to examine three-dimensional knee joint biomechanics and muscle activation differences during gait between asymptomatic and symptomatic individuals with radiographic knee osteoarthritis. A total of 54 asymptomatic and 59 symptomatic individuals with a Kellgren-Lawrence osteoarthritis radiographic grade of 2 underwent a comprehensive gait analysis to examine differences in the magnitude and patterns of the knee flexion angle, three-dimensional net resultant moments, and electromyography of the quadriceps, hamstrings, and gastrocnemii during over ground walking between the two groups.

Torque and Muscle Activation Impairment Along With Insulin Resistance Are Associated With Falls in Women With Fibromyalgia.

Góes, SM, Stefanello, JMF, Homann, D, Lodovico, A, Hubley-Kozey, CL, and Rodacki, ALF. Torque and muscle activation impairment along with insulin resistance are associated with falls in women with fibromyalgia. J Strength Cond Res 30(11): 3155-3164, 2016-Fibromyalgia (FM) is a chronic pain condition associated with reduced muscle strength, which can lead to functional incapacity and higher risk of falls.

Obesity is associated with higher absolute tibiofemoral contact and muscle forces during gait with and without knee osteoarthritis.

Background: Obesity is an important risk factor for knee osteoarthritis initiation and progression. However, it is unclear how obesity may directly affect the mechanical loading environment of the knee joint, initiating or progressing joint degeneration. The objective of this study was to investigate the interacting role of obesity and moderate knee osteoarthritis presence on tibiofemoral contact forces and muscle forces within the knee joint during walking gait.

Relationship between knee adduction moment patterns extracted using principal component analysis and discrete measures with different amplitude normalizations: Implications for knee osteoarthritis progression studies.

Background: Knee adduction moment discrete features (peaks and impulses) are commonly reported in knee osteoarthritis gait studies, but they do not necessarily capture loading patterns. Principal component analysis extracts dynamic patterns, but can be difficult to interpret. This methodological study determined relationships between external knee adduction moment discrete measures and principal component analysis features, and examined whether amplitude-normalization methods influenced differences in those with knee osteoarthritis who progressed to surgery versus those that did not.

Three-dimensional biomechanical gait characteristics at baseline are associated with progression to total knee arthroplasty.

Objective: To determine if baseline 3-dimensional (3-D) biomechanical gait patterns differed between those patients with moderate knee osteoarthritis (OA) who progressed to total knee arthroplasty (TKA) and those that did not, and whether these differences had predictive value.

Methods: Fifty-four patients with knee OA had ground reaction forces and segment motions collected during gait. 3-D hip, knee, and ankle angles and moments were calculated over the gait cycle.

Age-related changes in trunk neuromuscular activation patterns during a controlled functional transfer task include amplitude and temporal synergies.

While healthy aging is associated with physiological changes that can impair control of trunk motion, few studies examine how spinal muscle responses change with increasing age. This study examined whether older (over 65 years) compared to younger (20-45 years) adults had higher overall amplitude and altered temporal recruitment patterns of trunk musculature when performing a functional transfer task. Surface electromyograms from twelve bilateral trunk muscle (24) sites were analyzed using principal component analysis, extracting amplitude and temporal features (PCs) from electromyographic waveforms.

Knee joint biomechanics and neuromuscular control during gait before and after total knee arthroplasty are sex-specific.

The future of total knee arthroplasty (TKA) surgery will involve planning that incorporates more patient-specific characteristics. Despite known biological, morphological, and functional differences between men and women, there has been little investigation into knee joint biomechanical and neuromuscular differences between men and women with osteoarthritis, and none that have examined sex-specific biomechanical and neuromuscular responses to TKA surgery. The objective of this study was to examine sex-associated differences in knee kinematics, kinetics and neuromuscular patterns during gait before and after TKA.

Sit-to-stand transfer mechanics in healthy older adults: a comprehensive investigation of a portable lifting-seat device.

Purpose: To evaluate lower extremity mechanics and muscle activation associated with the sit-to-stand transfer using a portable lifting-seat device and to compare these data to an unassisted transfer in healthy young and older adults.

Methods: Bilateral lower extremity and low back musculature electromyography, three-dimensional leg and trunk motion, and ground reaction forces were recorded from 10 young (mean age = 25) and 10 older (mean age = 69) adults during five trials of (i) no assist and (ii) assisted transfers. Data were time normalized to represent the period of seat-off to standing.

Hip abductor function in individuals with medial knee osteoarthritis: Implications for medial compartment loading during gait.

Background: Hip abductor muscles generate moments of force that control lower extremity frontal plane motion. Strengthening these muscles has been a recent trend in therapeutic intervention studies for knee osteoarthritis. The current study investigated the relationship between hip abductor muscle function (strength and activation) and the net external knee adduction moment during gait in those with medial compartment knee osteoarthritis.

Temporal patterns of the trunk muscles remain altered in a low back-injured population despite subjective reports of recovery.

Objective: To compare temporal activation patterns from 24 abdominal and lumbar muscles between healthy subjects and those who reported recovery from recent low back injury (LBI).

Design: Cross-sectional comparative study.

Setting: University neuromuscular function laboratory.

Trunk neuromuscular pattern alterations during a controlled functional task in a low back injured group deemed ready to resume regular activities.

Background: Trunk neuromuscular alterations have been found in those with chronic low back pain, but less well studied are whether responses are altered in those deemed recovered following an injury. Furthermore, coordinated trunk muscle responses are deemed important for normal spinal function, but there are no studies of temporal patterns early after a low back injury. Determining whether altered trunk muscle patterns exist early after injury could improve our understanding of recovery by providing an objective assessment of functional recovery and risk of re-injury.

Reliability of principal components and discrete parameters of knee angle and moment gait waveforms in individuals with moderate knee osteoarthritis.

Gait measures are used to evaluate change in patients with knee osteoarthritis (OA), but reliability has not been fully established in this population. This study examined test-retest reliability of knee angle and moment gait waveform characteristics captured using discrete parameters and principal component analysis (PCA) in individuals with moderate knee OA. Participants (n=20) underwent three-dimensional gait analysis on two occasions.

Changes in knee joint muscle activation patterns during walking associated with increased structural severity in knee osteoarthritis.

Purpose: To determine whether alterations in knee joint muscle activation patterns during gait were related to structural severity determined by Kellgren-Lawrence (KL) radiographic grades, for those with a moderate knee OA classification.

Scope: Eighty-two individuals with knee OA, classified as moderate using a functional and clinical criterion were stratified on KL-grade (KL II, KL III and KL IV). Thirty-five asymptomatic individuals were matched for age and walking velocity.

Reliability of surface electromyographic recordings during walking in individuals with knee osteoarthritis.

To determine test-retest reliability of a surface electromyographic protocol designed to measure knee joint muscle activation during walking in individuals with knee osteoarthritis (OA). Twenty-one individuals with moderate medial compartment knee OA completed two gait data collections separated by approximately 1month. Using a standardized protocol, surface electromyograms from rectus femoris plus lateral and medial sites for the gastrocnemii, vastii and hamstring muscles were recorded during walking.

Changes in electromyographic activity of trunk muscles within the sub-acute phase for individuals deemed recovered from a low back injury.

Evidence indicates that previous low back injury (LBI) is a strong predictor for re-injury. The purpose of this study was to examine whether neuromuscular patterns remain altered in a LBI group who were deemed recovered. Surface electromyograms from 12-abdominal and 12-back extensors sites and motion variables were recorded from 33 LBI individuals (sub-acute phase) and 54 asymptomatic controls.

Body mass index affects knee joint mechanics during gait differently with and without moderate knee osteoarthritis.

Objective: Obesity is a highly cited risk factor for knee osteoarthritis (OA), but its role in knee OA pathogenesis and progression is not as clear. Excess weight may contribute to an increased mechanical burden and altered dynamic movement and loading patterns at the knee. The objective of this study was to examine the interacting role of moderate knee OA disease presence and obesity on knee joint mechanics during gait.