Concussed Neural Signature is Substantially Different than Fatigue Neural Signature in Non-concussed Controls.

Traumatic brain injuries can result in short-lived and long-lasting neurological impairment. Identifying the correct recovery timeframe is challenging, as balance-based metrics may be negatively impacted if testing is performed soon after exercise. Thirty-two healthy controls and seventeen concussed individuals performed a series of balance challenges, including virtual reality optical flow perturbation.

Practice day may be unnecessary prior to testing knee extensor strength in young healthy adults.

A practice session is common prior to strength testing. However, the benefits of practice have not been previously reported. The purpose of this study was to determine the effect of a practice session on peak torque, mean torque and between trial variability across three test days.

Implications of microscale lung damage for COVID-19 pulmonary ventilation dynamics: A narrative review.

The COVID-19 pandemic surges on as vast research is produced to study the novel SARS-CoV-2 virus and the disease state it induces. Still, little is known about the impact of COVID-19-induced microscale damage in the lung on global lung dynamics. This review summarizes the key histological features of SARS-CoV-2 infected alveoli and links the findings to structural tissue changes and surfactant dysfunction affecting tissue mechanical behavior similar to changes seen in other lung injury.

A Six-Year Review of the Biomedical Engineering in Simulations, Imaging, and Modeling Undergraduate Research Experience.

Undergraduate research continues to serve as an effective strategy for mitigating the effects of a leaky pipeline. Significant funding from institutions and government agencies has increased the number of students participating in undergraduate research. In this paper, we report on the six-year experience of a National Science Foundation funded Research Experiences for Undergraduates (REU) Site: Biomedical Engineering in Simulations, Imaging, and Modeling (BME-SIM).

Anterior-Posterior Balance Perturbation Protocol Using Lifelike Virtual Reality Environment.

Virtual reality (VR) paradigms have proved to be a valid method to challenge and perturb balance. There is little consensus in the literature on the best protocol design to perturb balance and induce postural sway. Current VR interventions still lack a well-defined standardized metric to generate a virtual environment that can perturb balance in an efficacious, lifelike, and repeatable manner.

Measurement of intrinsic foot stiffness in minimally and traditionally shod runners using ultrasound elastography: A pilot study.

Running is an activity with a consistently high injury rate. Running footwear design that mimics barefoot running has been proposed to reduce injury rate by increasing the strength of foot structures. However, there is little evidence to support this.

Simulations, Imaging, and Modeling: A Unique Theme for an Undergraduate Research Program in Biomechanics.

As the reliance on computational models to inform experiments and evaluate medical devices grows, the demand for students with modeling experience will grow. In this paper, we report on the 3-yr experience of a National Science Foundation (NSF) funded Research Experiences for Undergraduates (REU) based on the theme simulations, imaging, and modeling in biomechanics. While directly applicable to REU sites, our findings also apply to those creating other types of summer undergraduate research programs.

The effect of Nordic hamstring strength training on muscle architecture, stiffness, and strength.

Purpose: Hamstring strain injury is a frequent and serious injury in competitive and recreational sports. While Nordic hamstring (NH) eccentric strength training is an effective hamstring injury-prevention method, the protective mechanism of this exercise is not understood. Strength training increases muscle strength, but also alters muscle architecture and stiffness; all three factors may be associated with reducing muscle injuries.

Assessing the accuracy of subject-specific, muscle-model parameters determined by optimizing to match isometric strength.

Biomechanical models are sensitive to the choice of model parameters. Therefore, determination of accurate subject specific model parameters is important. One approach to generate these parameters is to optimize the values such that the model output will match experimentally measured strength curves.

Males and Females Respond Similarly to Walking With a Standardized, Heavy Load.

Females in the military sustain a higher incidence of lower extremity injuries compared to males. Previous investigations of gender differences during load carriage used loads normalized to body mass; as a result of anthropometric and strength differences between genders, this may partially normalize to strength, masking gender or size differences in response to load. We compared gait kinetics and kinematics between genders based on a standardized load, instead of loads relative to body mass.

Maximum height and minimum time vertical jumping.

The performance criterion in maximum vertical jumping has typically been assumed to simply raise the center of mass as high as possible. In many sporting activities minimizing movement time during the jump is likely also critical to successful performance. The purpose of this study was to examine maximum height jumps performed while minimizing jump time.

Heterogeneous fascicle behavior within the biceps femoris long head at different muscle activation levels.

Magnetic resonance and ultrasound imaging have shown hamstring strain injuries occur most often in the biceps femoris long head (BFLH), and particularly in the proximal vs. distal region of this muscle. Animal research and musculoskeletal modeling (MSK) have detected heterogeneous fascicle behavior within muscle regions, and within fascicles.

The relationships between muscle force steadiness and visual steadiness in young and old adults.

Since vision is used in studies of muscle force control, reduced muscle force control might be related to reduced visual ability. We investigated relationships between steadiness in eye movements and quadriceps muscle torque (a surrogate for force) during isometric contractions of constant and varying torques. Nineteen young adults with an average age of 20.

An examination of possible quadriceps force at the time of anterior cruciate ligament injury during landing: A simulation study.

Anterior cruciate ligament (ACL) rupture is a common and traumatic injury. Although, identifying the mechanism of ACL injury has received considerable research attention, there are still many unanswered questions. One proposed mechanism asserts that the ACL is injured due to an aggressive quadriceps muscle contraction.

Evaluation of muscles affected by myositis using magnetic resonance elastography.

Introduction: Idiopathic inflammatory myopathies (IIMs, or myositis) represent a group of autoimmune diseases that result in decreased muscle strength and/or endurance. Non-invasive tools to assess muscle may improve our understanding of the clinical and functional consequences of myopathies and their response to treatment. In this study we examine magnetic resonance elastography (MRE), a non-invasive technique that assesses the shear modulus (stiffness) of muscle, in IIM subjects.

An induced energy analysis to determine the mechanism for performance enhancement as a result of arm swing during jumping.

Arm swing during a jump can enhance performance. This study examined the mechanisms via which arm swing contributes to maximum vertical jump height. Two mechanisms have been proposed to explain how jump height can be increased by arm swing: production of additional energy or slow leg extension which may permit muscles to work on a more favorable region of the force-velocity curve.

Measurement of stiffness changes in immobilized muscle using magnetic resonance elastography.

Background: The isolated evaluation of changes in muscle following immobilization and disuse is a challenge in living subjects. The purpose of this study was to determine whether magnetic resonance elastography is capable of detecting these changes.

Methods: An animal model was created to produce a mild joint contracture following 42 days of one forelimb immobilization in a maximally flexed position with twice-daily passive exercise.

A critical examination of the maximum velocity of shortening used in simulation models of human movement.

The maximum velocity of shortening of a muscle is an important parameter in musculoskeletal models. The most commonly used values are derived from animal studies; however, these values are well above the values that have been reported for human muscle. The purpose of this study was to examine the sensitivity of simulations of maximum vertical jumping performance to the parameters describing the force-velocity properties of muscle.

Effect of collagen digestion on the passive elastic properties of diaphragm muscle in rat.

Effects of collagen digestion have been defined up to the fibril level. However, the question remains as to whether the alteration of skeletal muscle extracellular matrix (ECM) affects a muscle's passive elastic response. Various elastography methods have been applied as tools for evaluating the mechanical properties and ECM content of skeletal muscle.

The effect of triangular fibrocartilage complex injury on extensor carpi ulnaris function and friction.

Background: It has been previously shown that injury to the triangular fibrocartilage complex increases the moment arm of the extensor carpi ulnaris. This will reduce the force producing capacity of the muscle in some situations, but will also increase its mechanical advantage. It is also possible that the change in the tendon path may increase tendon friction, predisposing the patient to future repetitive motion injury.

Elbow strength and endurance in patients with a ruptured distal biceps tendon.

Background: Patients with complete distal biceps tendon ruptures complain of fatigability with repeated elbow flexion and forearm supination. Some studies have documented changes in strength, but limited information is available about the effects of biceps tendon rupture on endurance.

Hypothesis: A ruptured distal biceps tendon results in decreased strength and enducance.

Radiocapitellar joint stability with bipolar versus monopolar radial head prostheses.

Background: Bipolar and monopolar designs are both available for replacement of the radial head. Few data exist comparing the biomechanical characteristics of these 2 quite different prostheses. This study evaluated the relative contribution to radiocapitellar stability by concavity compression with these 2 types of radial head prostheses.

Stem diameter and micromotion of press fit radial head prosthesis: a biomechanical study.

Background: Aseptic loosening of the stem, ranging from mild periprosthetic lucency to symptomatic loosening leading to implant removal, has been reported in press fit radial head prostheses.

Hypothesis: The purpose of this study was to determine the effect of the stem diameter and insertion force on initial stability with a press fit radial head prosthesis designed for bone ingrowth.

Materials And Methods: Cadaveric radii were implanted with radial head prostheses of increasing stem diameter.

Feasibility of using magnetic resonance elastography to study the effect of aging on shear modulus of skeletal muscle.

A common complication associated with aging is the stiffening of skeletal muscles. The purpose of this study was to determine the ability of magnetic resonance elastography (MRE) to study this phenomenon in vivo. Twenty female subjects were included in the study with an age range of 50 to 70 years.

Wave attenuation as a measure of muscle quality as measured by magnetic resonance elastography: initial results.

Advances in imaging technologies such as magnetic resonance elastography (MRE) have allowed researchers to gain insights into muscle function in vivo. MRE has been used to examine healthy and diseased muscle by calculating shear modulus. However, additional information can be measured from visualizing a mechanical wave as it passes through a tissue.