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Journal of Biomechanics Mar 2023Running is one of the most common forms of physical activity for autistic adolescents. However, research examining their lower extremity dynamics is sparse. In...
Running is one of the most common forms of physical activity for autistic adolescents. However, research examining their lower extremity dynamics is sparse. In particular, no information exists regarding lower extremity joint stiffness in autistic adolescents. This study compared knee and ankle joint stiffness during the absorption phase of running between autistic adolescents and non-autistic controls. Motion capture and ground reaction forces were recorded for 22 autistic adolescents and 17 non-autistic age, sex, and BMI matched peers who ran at self-selected and standardized (3.0 m/s) speeds. Group × speed knee and ankle joint stiffness, change in moment, and range of motion were compared using mixed-model ANOVAs. There were no group × speed interactions for any variable. Autistic adolescents presented with significant (12 % and 19 %) reduced knee and ankle joint stiffness, respectively. In addition, autistic adolescents had significant reduced changes in knee and ankle joint moments by 11 % and 21 %, respectively, compared to their non-autistic peers. Only knee joint stiffness and knee joint moments were sensitive to running speed, each significantly increasing with speed by 6 %. Current literature suggests joint stiffness is an important mechanism for stability and usage of the stretch shortening cycle (or elastic recoil); as such, it is possible that the reduced ankle plantar flexor and knee extensor stiffness found in autistic adolescents in this study could be indicative of reduced efficiency during running. As group differences existed across both speeds, autistic adolescents may benefit from therapeutic and/or educational interventions targeting efficient running mechanics.
Topics: Adolescent; Humans; Biomechanical Phenomena; Lower Extremity; Knee; Knee Joint; Ankle Joint; Running
PubMed: 36780731
DOI: 10.1016/j.jbiomech.2023.111478 -
Hand Surgery & Rehabilitation Oct 2018This lecture will focus on posttraumatic finger contractures affecting the metacarpophalangeal (MCP) and proximal interphalangeal (PIP) joints in adults. The... (Review)
Review
This lecture will focus on posttraumatic finger contractures affecting the metacarpophalangeal (MCP) and proximal interphalangeal (PIP) joints in adults. The pathophysiology, main causes and essential rehabilitation methods that can be used before resorting to surgical treatment are described, along with the clinical examination. The goal is to define the surgical indications, even though the literature shows the functional outcomes are disappointing. While there is little to no change in a joint's angular amplitude, the functional range of motion can be improved. There is practically no functional improvement except in cases of MCP extension contracture. For the PIP joint, the aim is to shift the range of motion into the functional range. Surgical approaches, surgical techniques and rehabilitation protocols are described in detail.
Topics: Contracture; External Fixators; Finger Injuries; Finger Joint; Humans; Metacarpophalangeal Joint; Occupational Therapy; Physical Therapy Modalities; Range of Motion, Articular; Splints
PubMed: 30033359
DOI: 10.1016/j.hansur.2018.06.003 -
PloS One 2015Individual joint deviations are often identified in the analysis of cerebral palsy (CP) gait. However, knowledge is limited as to how these deviations affect the control...
Individual joint deviations are often identified in the analysis of cerebral palsy (CP) gait. However, knowledge is limited as to how these deviations affect the control of the locomotor system as a whole when striving to meet the demands of walking. The current study aimed to bridge the gap by describing the control of the locomotor system in children with diplegic CP in terms of their leg stiffness, both skeletal and muscular components, and associated joint stiffness during gait. Twelve children with spastic diplegia CP and 12 healthy controls walked at a self-selected pace in a gait laboratory while their kinematic and forceplate data were measured and analyzed during loading response, mid-stance, terminal stance and pre-swing. For calculating the leg stiffness, each of the lower limbs was modeled as a non-linear spring, connecting the hip joint center and the corresponding center of pressure, with varying stiffness that was calculated as the slope (gradient) of the axial force vs. the deformation curve. The leg stiffness was further decomposed into skeletal and muscular components considering the alignment of the lower limb. The ankle, knee and hip of the limb were modeled as revolute joints with torsional springs whose stiffness was calculated as the slope of the moment vs. the angle curve of the joint. Independent t-tests were performed for between-group comparisons of all the variables. The CP group significantly decreased the leg stiffness but increased the joint stiffness during stance phase, except during terminal stance where the leg stiffness was increased. They appeared to rely more on muscular contributions to achieve the required leg stiffness, increasing the muscular demands in maintaining the body posture against collapse. Leg stiffness plays a critical role in modulating the kinematics and kinetics of the locomotor system during gait in the diplegic CP.
Topics: Biomechanical Phenomena; Case-Control Studies; Cerebral Palsy; Child; Gait; Humans; Joints; Leg; Mechanical Phenomena; Muscles; Walking
PubMed: 26629700
DOI: 10.1371/journal.pone.0143967 -
The Journal of Arthroplasty Apr 2023Stiffness after primary total knee arthroplasty (TKA) is debilitating and poorly understood. A heterogenous approach to the treatment is often utilized, including both... (Observational Study)
Observational Study
BACKGROUND
Stiffness after primary total knee arthroplasty (TKA) is debilitating and poorly understood. A heterogenous approach to the treatment is often utilized, including both nonoperative and operative treatment modalities. The purpose of this study was to examine the prevalence of treatments used between stiff and non-stiff TKA groups and their financial impact.
METHODS
An observational cohort study was conducted using a large database. A total of 12,942 patients who underwent unilateral primary TKA from January 1, 2017, to December 31, 2017, were included. Stiffness after TKA was defined as manipulation under anesthesia and a diagnosis code of stiffness or ankylosis, and subsequent diagnosis and procedure codes were used to identify the prevalence and financial impact of multiple common treatment options.
RESULTS
The prevalence of stiffness after TKA was 6.1%. Stiff patients were more likely to undergo physical therapy, medication, bracing, alternative treatment, clinic visits, and reoperation. Revision surgery was the most common reoperation in the stiff TKA group (7.6%). The incidence of both arthroscopy and revision surgery were higher in the stiff TKA population. Dual component revisions were costlier for patients who had stiff TKAs ($65,771 versus $48,287; P < .05). On average, patients who had stiffness after TKA endured costs from 1.5 to 7.5 times higher than the cost of their non-stiff counterparts during the 2 years following index TKA.
CONCLUSION
Patients who have stiffness after primary TKA face significantly higher treatment costs for both operative and nonoperative treatments than patients who do not have stiffness.
Topics: Humans; Arthroplasty, Replacement, Knee; Knee Joint; Range of Motion, Articular; Treatment Outcome; Cohort Studies; Reoperation; Retrospective Studies
PubMed: 36947505
DOI: 10.1016/j.arth.2022.10.040 -
Computer Methods in Biomechanics and... 2015Knee joints are subject to large compression forces in daily activities. Due to artefact moments and instability under large compression loads, biomechanical studies...
Knee joints are subject to large compression forces in daily activities. Due to artefact moments and instability under large compression loads, biomechanical studies impose additional constraints to circumvent the compression position-dependency in response. To quantify the effect of compression on passive knee moment resistance and stiffness, two validated finite element models of the tibiofemoral (TF) joint, one refined with depth-dependent fibril-reinforced cartilage and the other less refined with homogeneous isotropic cartilage, are used. The unconstrained TF joint response in sagittal and frontal planes is investigated at different flexion angles (0°, 15°, 30° and 45°) up to 1800 N compression preloads. The compression is applied at a novel joint mechanical balance point (MBP) identified as a point at which the compression does not cause any coupled rotations in sagittal and frontal planes. The MBP of the unconstrained joint is located at the lateral plateau in small compressions and shifts medially towards the inter-compartmental area at larger compression forces. The compression force substantially increases the joint moment-bearing capacities and instantaneous angular rigidities in both frontal and sagittal planes. The varus-valgus laxities diminish with compression preloads despite concomitant substantial reductions in collateral ligament forces. While the angular rigidity would enhance the joint stability, the augmented passive moment resistance under compression preloads plays a role in supporting external moments and should as such be considered in the knee joint musculoskeletal models.
Topics: Biomechanical Phenomena; Cartilage, Articular; Compressive Strength; Finite Element Analysis; Humans; Knee Joint; Ligaments; Pressure; Range of Motion, Articular; Weight-Bearing
PubMed: 23682906
DOI: 10.1080/10255842.2013.795555 -
The American Journal of Sports Medicine Jun 2023Overuse ligament and tendon injuries are prevalent among recreational and competitive adolescent athletes. In vitro studies of the ligament and tendon suggest that...
BACKGROUND
Overuse ligament and tendon injuries are prevalent among recreational and competitive adolescent athletes. In vitro studies of the ligament and tendon suggest that mechanical overuse musculoskeletal injuries begin with collagen triple-helix unraveling, leading to collagen laxity and matrix damage. However, there are little in vivo data concerning this mechanism or the physiomechanical response to collagen disruption, particularly regarding the anterior cruciate ligament (ACL).
PURPOSE
To develop and validate a novel in vivo animal model for investigating the physiomechanical response to ACL collagen matrix damage accumulation and propagation in the ACL midsubstance, fibrocartilaginous entheses, and subchondral bone.
STUDY DESIGN
Controlled laboratory study.
METHODS
C57BL/6J adolescent inbred mice underwent 3 moderate to strenuous ACL fatigue loading sessions with a 72-hour recovery between sessions. Before each session, randomly selected subsets of mice (n = 12) were euthanized for quantifying collagen matrix damage (percent collagen unraveling) and ACL mechanics (strength and stiffness). This enabled the quasi-longitudinal assessment of collagen matrix damage accrual and whole tissue mechanical property changes across fatigue sessions. Additionally, all cyclic loading data were quantified to evaluate changes in knee mechanics (stiffness and hysteresis) across fatigue sessions.
RESULTS
Moderate to strenuous fatigue loading across 3 sessions led to a 24% weaker ( = .07) and 35% less stiff ( < .01) ACL compared with nonloaded controls. The unraveled collagen densities within the fatigued ACL and entheseal matrices after the second and third sessions were 38% ( < .01) and 15% ( = .02) higher compared with the nonloaded controls.
CONCLUSION
This study confirmed the hypothesis that in vivo ACL collagen matrix damage increases with tissue fatigue sessions, adversely impacting ACL mechanical properties. Moreover, the in vivo ACL findings were consistent with in vitro overloading research in humans.
CLINICAL RELEVANCE
The outcomes from this study support the use of this model for investigating ACL overuse injuries.
Topics: Humans; Adolescent; Mice; Animals; Anterior Cruciate Ligament; Mice, Inbred C57BL; Anterior Cruciate Ligament Reconstruction; Knee Joint; Anterior Cruciate Ligament Injuries; Collagen; Cumulative Trauma Disorders; Biomechanical Phenomena
PubMed: 37092727
DOI: 10.1177/03635465231165753 -
Journal of Strength and Conditioning... Dec 2018Powell, DW and Williams, DSB. Changes in vertical and joint stiffness in runners with advancing age. J Strength Cond Res 32(12): 3425-3431, 2018-Age-related changes in...
Powell, DW and Williams, DSB. Changes in vertical and joint stiffness in runners with advancing age. J Strength Cond Res 32(12): 3425-3431, 2018-Age-related changes in the neuromuscular system underlie reduced performance and injury but may be mitigated through regular physical activity. It was hypothesized that older (OLD) compared with young (YOUNG) adults would exhibit greater vertical and joint stiffness when running at 3.35 m·s. Nine YOUNG and 10 OLD runners performed over ground running trials while three-dimensional biomechanics were recorded. Ankle and knee joint angles, moments and stiffness values were compared between YOUNG & OLD. YOUNG had smaller vertical stiffness (p = 0.01; YOUNG: 32.8 ± 3.6; OLD: 38.1 ± 5.7) and greater joint stiffness than OLD at the ankle (p = 0.04; YOUNG: 0.134 ± 0.021; OLD: 0.118 ± 0.017) and knee (p = 0.01; YOUNG: 0.119 ± 0.016; OLD: 0.098 ± 0.014). YOUNG exhibited greater peak knee flexion angles (p = 0.04; YOUNG: 43.4 ± 6.5°; OLD: 39.1 ± 2.6°), and peak ankle plantarflexion (p = 0.02; YOUNG: -2.8 ± 0.4 Nm·kg; OLD: -2.5 ± 0.1 Nm·kg) and knee extension moments (p < 0.01; 2.6 ± 0.3 Nm·kg; OLD: 2.1 ± 0.2 Nm·kg) than OLD whereas no differences were observed in peak ankle dorsiflexion angles (p = 0.44; YOUNG: 23.6 ± 4.2°; OLD: 23.4 ± 2.1°). The findings of this study suggest that OLD compared with YOUNG adults adopt altered lower extremity biomechanics. These altered running biomechanics by seek to minimize the metabolic cost of running or may be a function of reduced lower extremity strength and power.
Topics: Adult; Age Factors; Aged; Ankle Joint; Biomechanical Phenomena; Humans; Knee Joint; Lower Extremity; Middle Aged; Range of Motion, Articular; Running
PubMed: 28240709
DOI: 10.1519/JSC.0000000000001869 -
IEEE Transactions on Neural Systems and... 2022Research and the commercial use of exoskeletons that augment human activities are rapidly growing. However, the progress of the two is hindered by the time-consuming and...
Research and the commercial use of exoskeletons that augment human activities are rapidly growing. However, the progress of the two is hindered by the time-consuming and costly process of designing and evaluating the exoskeleton. One of the solutions to reduce both is the use of simulations that model the users, exoskeleton, and their interaction. At the same time, most simulations focus on continuous tasks, such as walking, running, and industrial activities. The augmentation of human capability is essential in fast motion tasks (i.e., jumping, throwing), where the muscles are producing their maximum force. Thus, this study implemented a simulation of passive exoskeleton-human interactions using OpenSim and Moco software for optimal control to find muscle excitation that maximizes vertical jump height. The models include a planar human model with ankle, knee, and hip joints. The muscles were modeled as torque actuators for each joint, with a flexor and an extensor, and passive torques representing each joint's ligaments. The simulation was used to study: a) the effect of different spring stiffness at the knee, hip, and ankle joints and combinations of these joints; b) multi-joints vs. single joints; c) the effect of an elliptic pulley and different initial engagement angle for springs. The results revealed that the jump height increased as the spring became stiffer, up to a maximum point. For a single joint, the knee exoskeleton was the most effective, compared with the hip and ankle joint exoskeletons. The multi-joint exoskeleton was slightly better than the single knee joint. If maximum spring tension is a limiting factor, an elliptic pulley has an advantage relative to a round pulley. An initial angle of engagement (with equal work) other than zero up to approximately 50 degrees does not decrease the jump height.
Topics: Ankle Joint; Biomechanical Phenomena; Exoskeleton Device; Hip Joint; Humans; Torque; Walking
PubMed: 36155480
DOI: 10.1109/TNSRE.2022.3209575 -
Scandinavian Journal of Medicine &... Oct 2014The ability of the nervous system to accommodate changes to joint mechanics is crucial in the maintenance of joint stability and the prevention of injury. This... (Review)
Review
The ability of the nervous system to accommodate changes to joint mechanics is crucial in the maintenance of joint stability and the prevention of injury. This neuromechanical coupling is achieved through several mechanisms such as the central and peripheral regulation of muscle tone and subsequent alterations to joint stiffness. Following joint injury, such as a ligamentous sprains, some patients develop functional instability or require surgery to stabilize the joint, while others are able to cope and display limited impairments. Several researchers have attempted to explain these divergent outcomes, although research using proprioceptive tasks and quantifying reaction times has led to equivocal results. Recent innovations have allowed for the simultaneous measurement of mechanical and nervous system function among these subsets. The intent of this review was to explore the relationships between joint stiffness and nervous system function, and how it changes following injury. By better understanding these mechanisms, researchers and clinicians may better develop and implement rehabilitation protocols to target individual deficits among injured populations.
Topics: Adaptation, Physiological; Biomechanical Phenomena; Central Nervous System; Humans; Joint Instability; Joints; Muscle, Skeletal; Peripheral Nerves; Proprioception; Range of Motion, Articular; Stress, Mechanical
PubMed: 25371932
DOI: 10.1111/sms.12181 -
Journal of Biomechanics Aug 2023The aim of this study was to determine the muscle co-activations and joint stiffnesses around the hip, knee, and ankle during different walking speeds and to define the...
The aim of this study was to determine the muscle co-activations and joint stiffnesses around the hip, knee, and ankle during different walking speeds and to define the relationships between muscle co-activation and joint stiffness. Twenty-seven healthy subjects (age: 19.6 ± 2.2 years, height: 176.0 ± 6.0 cm, mass: 69.7 ± 8.9 kg) were recruited. Muscle co-activations (CoI) and lower limb joints stiffnesses were investigated during stance phase at different walking speeds using Repeated Measures ANOVA with Sidak post-hoc tests. Correlations between muscle co-activations, joints stiffnesses, and walking speeds were also investigated using Pearson Product Moment correlations. The results indicated that the hip and ankle joints stiffness increased with walking speed (p < 0.001) during the weight acceptance phase, and positive correlations were seen between walking speed and Rectus Femoris (RF) and Biceps Femoris (BF) CoI (p < 0.001), and a negative correlation was seen between walking speed and tibialis anterior (TA) and lateral gastrocnemius (LG) CoI (p < 0.001) during the weight acceptance phase, and the RF/BF CoI during pre-swing. These results provide new information on the variations in muscle co-activation around the hip, knee and ankle joints and their association with joint stiffness, and on the responses of stiffness and muscle co-activation to walking speed. The techniques presented could have further application and help our understanding of the effects of gait retraining and injury mechanisms.
Topics: Humans; Adolescent; Young Adult; Adult; Walking Speed; Walking; Electromyography; Gait; Muscle, Skeletal; Knee Joint; Lower Extremity; Ankle Joint; Biomechanical Phenomena
PubMed: 37423119
DOI: 10.1016/j.jbiomech.2023.111715