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Multifidus Denervation After Radiofrequency Ablation of the Medial Nerve Alters the Biomechanics of the Spine—A Computational Study

Faris A. Almalki and Daniel H. Cortes

Radiofrequency ablation of the medial branch is commonly used to treat chronic low back pain involving facet joints, which accounts for 12% to 37% of the total cases of chronic low back pain. An adverse effect of this procedure is the denervation of the multifidus muscle, which may lead to its atrophy which can affect the spine and possibly disc degeneration. This study aims to quantify changes in joint angles and loading caused by multifidus denervation after radiofrequency ablation. AnyBody model of the torso was used to evaluate intervertebral joints in flexion, lateral bending, and torsion. Force-dependent kinematics was used to calculate joint angles and forces. These dependent variables were investigated in intact multifidus, unilateral, and bilateral ablations of L3L4, L4L5, and L5S1 joints. The results showed pronounced angular joint changes, especially in bilateral ablations in flexion, when compared with other cases. The same changes’ trend from intact to unilaterally then bilaterally ablated multifidus occurred in joint angles of lateral bending. Meanwhile, joint forces were not adversely affected. These results suggest that multifidus denervation after radiofrequency ablation affects spinal mechanics. Such changes may be associated with abnormal tissue deformations and stresses that can potentially alter their mechanobiology and homeostasis, thereby possibly affecting the health of the spine.

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Use of Target Information for Preparing Initial Motor Command of Target Force Production Task

Koichi Hiraoka, Keita Hashimoto, and Takumi Fukuchi

The present study examined how humans use the target information provided immediately before the onset of motor output to prepare the initial motor command in the target force production task. Twenty healthy individuals participated in this study. A target cursor indicating the target force, and a force cursor indicating the force produced with index finger flexion were presented, and participants produced force in response to the appearance of the force cursor so that it moved toward the target cursor as fast as possible. The rate of force development in a time window of 0–100 ms after the onset of force development, representing the intensity of the initial motor command without online feedback adjustment, was measured. The present findings support the hypotheses that humans use the target information provided immediately before the onset of motor output to prepare the initial motor command, and they simultaneously prepare the initial motor command for the intermediate of multiple potential targets using the information of targets provided in previous trials. Another hypothesis, that humans use the information of the target or motor process of the trial immediately before the current trial to prepare the initial motor command, was not supported.

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Increased Risk of Falling in Older Adults When Coordinating Obstacle Avoidance and Grasping

Janine Carvalho Valentino Camargos, Gabriela Vigorito Magalhães, Letícia Munhoz Avellar, Anselmo Frizera, and Natalia Madalena Rinaldi

This study aimed to investigate the kinematic changes in obstacle avoidance and prehension tasks performed simultaneously by older adults with a history of falls at different levels of task difficulty. Twenty-six older adults were divided into faller and nonfaller groups. The experimental protocol was divided into two different tasks: walking with obstacle avoidance and walking with obstacle avoidance combined with a reach-to-grasp task. Two types of sensors (Kinect v2 and Leap Motion Controller, respectively) were used to analyze gait and grasp. Fallers presented kinematic changes associated with the grasping task during obstacle avoidance, such as a decrease in the velocity of the center of mass and the step length, an increase in the step width, a decrease in toe–obstacle horizontal distance, and an increase in vertical foot clearance distance, and an increase in movement time in the grasping task compared with nonfallers. To cope with the obstacle avoidance demands of both walking and grasping, fallers turned to a specific sequencing strategy. While slowing down, they attended first to the grasping task and then to crossing the obstacle on the floor.

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Prediction of Model Generated Patellofemoral Joint Contact Forces Using Principal Component Prediction and Reconstruction

Myles Ashall, Mitchell G.A. Wheatley, Chris Saliba, Kevin J. Deluzio, and Michael J. Rainbow

It is not currently possible to directly and noninvasively measure in vivo patellofemoral joint contact force during dynamic movement; therefore, indirect methods are required. Simple models may be inaccurate because patellofemoral contact forces vary for the same knee flexion angle, and the patellofemoral joint has substantial out-of-plane motion. More sophisticated models use 3-dimensional kinematics and kinetics coupled to a subject-specific anatomical model to predict contact forces; however, these models are time consuming and expensive. We applied a principal component analysis prediction and regression method to predict patellofemoral joint contact forces derived from a robust musculoskeletal model using exclusively optical motion capture kinematics (external approach), and with both patellofemoral and optical motion capture kinematics (internal approach). We tested this on a heterogeneous population of asymptomatic subjects (n = 8) during ground-level walking (n = 12). We developed equations that successfully capture subject-specific gait characteristics with the internal approach outperforming the external. These approaches were compared with a knee-flexion based model in literature (Brechter model). Both outperformed the Brechter model in interquartile range, limits of agreement, and the coefficient of determination. The equations generated by these approaches are less computationally demanding than a musculoskeletal model and may act as an effective tool in future rapid gait analysis and biofeedback applications.

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A Narrative Review of Personalized Musculoskeletal Modeling Using the Physiome and Musculoskeletal Atlas Projects

Justin Fernandez, Vickie Shim, Marco Schneider, Julie Choisne, Geoff Handsfield, Ted Yeung, Ju Zhang, Peter Hunter, and Thor Besier

In this narrative review, we explore developments in the field of computational musculoskeletal model personalization using the Physiome and Musculoskeletal Atlas Projects. Model geometry personalization; statistical shape modeling; and its impact on segmentation, classification, and model creation are explored. Examples include the trapeziometacarpal and tibiofemoral joints, Achilles tendon, gastrocnemius muscle, and pediatric lower limb bones. Finally, a more general approach to model personalization is discussed based on the idea of multiscale personalization called scaffolds.

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Perceptions of High-Intensity Interval Training Among People With Spinal Cord Injury: A Mixed-Methods Analysis

Joseph Peters, Kellie Halloran, Alexander Teague, Emily Erlenbach, Libak Abou, Mariana Kersh, and Ian Rice

This mixed-method project investigated how people with spinal cord injury perceive high-intensity interval training (HIIT). Using a recumbent hand cycle, 11 active men and 9 active women with spinal cord injury or related disease participated in a single HIIT and moderate-intensity continuous training (MICT) session. Following exercise, participants completed surveys assessing enjoyment, self-efficacy, and outcome expectations. Ten participants were randomly selected to participate in a semistructured interview to assess perceptions toward HIIT. Quantitative survey data revealed that participants trended toward enjoying HIIT over MICT (p = .06) with similar levels of self-efficacy and outcome expectations toward HIIT and MICT (p > .05). Qualitative data revealed that participants believed HIIT would enhance long-term physical and self-evaluative outcomes; several barriers emerged that could prevent widespread adoption among the general population with spinal cord injury. Results support HIIT as a viable exercise option, although research should begin exploring ways to remove HIIT-related barriers that people with spinal cord injury may encounter.

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Modeling Human Suboptimal Control: A Review

Alex Bersani, Giorgio Davico, and Marco Viceconti

This review paper provides an overview of the approaches to model neuromuscular control, focusing on methods to identify nonoptimal control strategies typical of populations with neuromuscular disorders or children. Where possible, the authors tightened the description of the methods to the mechanisms behind the underlying biomechanical and physiological rationale. They start by describing the first and most simplified approach, the reductionist approach, which splits the role of the nervous and musculoskeletal systems. Static optimization and dynamic optimization methods and electromyography-based approaches are summarized to highlight their limitations and understand (the need for) their developments over time. Then, the authors look at the more recent stochastic approach, introduced to explore the space of plausible neural solutions, thus implementing the uncontrolled manifold theory, according to which the central nervous system only controls specific motions and tasks to limit energy consumption while allowing for some degree of adaptability to perturbations. Finally, they explore the literature covering the explicit modeling of the coupling between the nervous system (acting as controller) and the musculoskeletal system (the actuator), which may be employed to overcome the split characterizing the reductionist approach.

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Open Foot Stance Reduces Lead Knee Joint Loading During Golf Swing

Hannah Stokes, Rafael Escamilla, Joseph Bellapianta, Hongsheng Wang, Tyson Beach, Dave Frost, and Naiquan Zheng

Foot stance and club type’s relationship with lead knee joint biomechanics and possible involvement with injury incidences in amateur golfers have not been evaluated. This study included 16 male right-handed amateur golfers who performed golf swings with 2 different foot stances (straight and open) using 4 different club types (driver, 3 iron, 6 iron, and 9 iron) while standing on 2 force plates in a motion capture laboratory. A custom program calculated the kinematics and kinetics of the lead knee. Overall, the open stance reduced most translations, rotations, forces, and torques of the lead knee in all 4 club types when compared with the straight stance. The open stance reduced the rotation motion (−28%), compressive force (−5%), and rotation torque (−9%) when compared with the straight stance, which are the highest contributors to grinding of cartilage. The driver club had significantly larger values in most translations, rotations, forces, and torques when compared among the 4 club types. The open stance reduced the rotation motion, compressive force, and rotation torque in the lead knee joint compared with the straight stance. Lead knee joint biomechanics should be monitored to reduce injury in amateur golfers.

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Relationships Between Throwing Yips in Baseball, Experiential Avoidance, Cognitive Fusion, Values, and Social Factors

Kazuya Inoue, Tatsuto Yamada, and Tomu Ohtsuki

Despite the high prevalence of yips, a psychoneuromuscular impairment affecting fine motor skills in sports performance, the specific aspects of its causality and treatment have not been identified or verified. This cross-sectional study examined psychosocial factors relating to throwing yips in baseball. Amateur baseball players (N = 292) living in Japan completed a self-report questionnaire on their anxiety/fear about throwing the ball, the Acceptance and Action Questionnaire-II, the Cognitive Fusion Questionnaire, the Short Fear of Negative Evaluation Scale, and self-reports evaluating values and social factors relevant to baseball. A hierarchical multiple regression analysis indicated that a low values-based throwing score, a high Cognitive Fusion Questionnaire score, and overreprimanding others’ mistakes were positively associated with baseball players’ yips symptoms. These results suggest that changing the context of playing baseball, reducing cognitive fusion, and improving coaching methods could reduce the risk of baseball players’ throwing yips.

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Screening of Depression and Mental Health in Elite Youth Sports: Differences in Risk Estimation Between the PHQ-2 and the WHO-5

Jens Kleinert, Jeannine Ohlert, and Marion Sulprizio

This study aims to examine whether the risk for depression differs between using a disease- and a health-oriented instrument in elite youth sport and to uncover relationships of risk with concern to age, sex, type of sport, and level of performance. A sample of 549 eleven- to twenty-one-year-old elite athletes were screened using the German versions of the Patient Health Questionnaire-2 (PHQ-2) and the WHO Well-Being Index-5 (WHO-5). For external validity, the state of physical well-being and mood state, as well as recovery measures, were assessed. The proportions of athletes at high risk for mental health problems were 11.3% (PHQ-2) and 12.8% (WHO-5) of the participants. Young athletes (<15 years old) and male athletes showed lower risk values compared with older or female athletes. Moreover, PHQ-2 and WHO-5 values correlated with physical well-being and subjective sleep parameters. Both instruments were practical and diagnostically conclusive. Further studies on the validation of the instruments are recommended.