Role of loading on head stability and effective neck stiffness and viscosity

Simoneau, Martin; Denninger, Marc; Hain, Timothy C.

doi:10.1016/j.jbiomech.2008.05.002

Cited by 45 publications

(33 citation statements)

References 30 publications

(37 reference statements)

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“…This group found that decreased peak angular velocities of the head resulted during increased cervical muscle activation in response to pre-loading. 37 Collectively, these studies suggest that “bracing for impact” may be an effective strategy for reducing the risk of concussion associated with a sport collision by reducing the magnitude of post-impact head kinematics. Furthermore, these results suggest that “heads up” coaching and training strategies aimed at improving an athlete's sense of awareness of their surroundings and their anticipation of body collisions may be an effective means for improving player safety by facilitating cervical muscle activation to brace for impact.…”

Section: Discussionmentioning

confidence: 99%

“…This differs from prior studies employing similar impulsive loading techniques. 25, 37, 42 This protocol decision was largely driven by participant safety considerations, especially in the pediatric athletes. Given the significant size heterogeneity among study participants, there was concern that the load magnitude required to generate sufficient head motion for kinematic analysis in the largest adult participants could be potentially injurious to the smaller pediatric participants.…”

Section: Discussionmentioning

confidence: 99%

“…The custom loading apparatus was similar to experimental devices previously developed to apply impulsive loads to subjects' heads in the sagittal plane. 25, 37, 42 …”

Section: Methodsmentioning

confidence: 99%

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Effect of Neck Muscle Strength and Anticipatory Cervical Muscle Activation on the Kinematic Response of the Head to Impulsive Loads

et al. 2014

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Background Greater neck strength and activating the neck muscles to brace for impact are both thought to reduce an athlete's risk of concussion during a collision by attenuating the head's kinematic response after impact. However, the literature reporting the neck's role in controlling postimpact head kinematics is mixed. Furthermore, these relationships have not been examined in the coronal or transverse planes or in pediatric athletes. Hypotheses In each anatomic plane, peak linear velocity (DV) and peak angular velocity (Dv) of the head are inversely related to maximal isometric cervical muscle strength in the opposing direction (H1). Under impulsive loading, DV and Dv will be decreased during anticipatory cervical muscle activation compared with the baseline state (H2). Study Design Descriptive laboratory study. Methods Maximum isometric neck strength was measured in each anatomic plane in 46 male and female contact sport athletes aged 8 to 30 years. A loading apparatus applied impulsive test forces to athletes' heads in flexion, extension, lateral flexion, and axial rotation during baseline and anticipatory cervical muscle activation conditions. Multivariate linear mixed models were used to determine the effects of neck strength and cervical muscle activation on head DV and Dv. Results Greater isometric neck strength and anticipatory activation were independently associated with decreased head DV and Dv after impulsive loading across all planes of motion (all P\.001). Inverse relationships between neck strength and head DV and Dv presented moderately strong effect sizes (r = 0.417 to r = 0.657), varying by direction of motion and cervical muscle activation. Conclusion In male and female athletes across the age spectrum, greater neck strength and anticipatory cervical muscle activation (“bracing for impact”) can reduce the magnitude of the head's kinematic response. Future studies should determine whether neck strength contributes to the observed sex and age group differences in concussion incidence. Clinical Relevance Neck strength and impact anticipation are 2 potentially modifiable risk factors for concussion. Interventions aimed at increasing athletes' neck strength and reducing unanticipated impacts may decrease the risk of concussion associated with sport participation.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Effect of Neck Muscle Strength and Anticipatory Cervical Muscle Activation on the Kinematic Response of the Head to Impulsive Loads

et al. 2014

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“…These intervals were based on the range reported in the literature (e.g. 40–140 ms [10]; 50 ms [12], [41]; 60 ms [15]; 150 ms [14], [42]. p KBI was optimized by minimizing the following error criterion that is only sensitive to differences in the shape of the responses …”

Section: Methodsmentioning

confidence: 99%

In Vivo Dynamics of the Musculoskeletal System Cannot Be Adequately Described Using a Stiffness-Damping-Inertia Model

Kistemaker

Rozendaal

2011

PLoS ONE

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BackgroundVisco-elastic properties of the (neuro-)musculoskeletal system play a fundamental role in the control of posture and movement. Often, these properties are described and identified using stiffness-damping-inertia (KBI) models. In such an approach, perturbations are applied to the (neuro-)musculoskeletal system and subsequently KBI-model parameters are optimized to obtain a best fit between simulated and experimentally observed responses. Problems with this approach may arise because a KBI-model neglects critical aspects of the real musculoskeletal system.Methodology/Principal FindingsThe purpose of this study was to analyze the relation between the musculoskeletal properties and the stiffness and damping estimated using a KBI-model, to analyze how this relation is affected by the nature of the perturbation and to assess the sensitivity of the estimated stiffness and damping to measurement errors. Our analyses show that the estimated stiffness and damping using KBI-models do not resemble any of the dynamical parameters of the underlying system, not even when the responses are very accurately fitted by the KBI-model. Furthermore, the stiffness and damping depend non-linearly on all the dynamical parameters of the underlying system, influenced by the nature of the perturbation and the time interval over which the KBI-model is optimized. Moreover, our analyses predict a very high sensitivity of estimated parameters to measurement errors.Conclusions/SignificanceThe results of this study suggest that the usage of stiffness-damping-inertia models to investigate the dynamical properties of the musculoskeletal system under control by the CNS should be reconsidered.

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“…Both effective stiffness and damping increased as the static torque magnitude increased. Simoneau et al (2008) examined the effect of preload on head stability using sudden perturbations. Seven healthy participants (4 males and 3 females) were exposed to sudden head perturbations using 1 kg load in the backward and forward directions at different preload conditions (0.22, 0.44, 0.66, 0.88 N).…”

Section: Load and Preload Effectmentioning

confidence: 99%

Post fatigue changes in the stability of cervical spine

Zreiqat¹

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POST FATIGUE CHANGES IN THE STABILITY OF CERVICAL SPINE Majed M. Zreiqat Musculoskeletal disorders (MSDs) of the neck or cervical spine are a common problem in the modern workforce. An annual prevalence of 30% to 50% for neck pain among the general adult population was reported by the Task Force of Bone and Joint Decade on Neck Pain. Physical work demands, such as sustained static postures, sub-maximal repetitive arm exertions, and forceful arm exertions are consistently identified as possible risk factors for cervical spine MSDs. Most of these exertions induce neck muscle fatigue which may affect the stability of the cervical spine. A less stable spine can be both a cause and consequence of spinal pain. The effect of muscle fatigue on the stability of the cervical spine is currently not well understood. The objective in this study was to quantify the post-fatigue changes and recovery of the cervical spine's stability. Specifically, the flexion-relaxation phenomenon (FRP) and sudden perturbations (SP) procedures were used to study the variables that influence the stability of the cervical spine. The FRP explains the synergistic load sharing between the muscles and viscoelastic elements (ligaments, discs, capsules, and fascia). The SP protocol allows quantification of the muscle reflex responses necessary to maintain spinal stability. Twenty human participants (10 male and 10 female) were recruited for data collection and the Sorenson protocol was utilized to induce neck muscle fatigue. Surface electromyography and optical motion capture systems were used to measure neck muscle activation and head-neck posture, respectively. A six degree of freedom force torque sensor was used to record the force profile data during the SP procedure. Localized muscle fatigue significantly reduced the flexion-relaxation ratio from 4.88 ± 0.81 pre-fatigue to 3.33 ± 0.57 post-fatigue. A post-fatigue decrease was also observed in the onset and offset angles by about 16% and 5%, respectively, resulting in an expansion of the myoelectric silence period by 17.2%. The intrinsic stiffness of cervical spine was reduced from 975.75 ± 85.87 Kg/sec 2 pre-fatigue to 826.31 ± 90.76 Kg/sec 2 post-fatigue. The corresponding change in the effective stiffness was from 1404.64 ± 122.31 Kg/sec 2 to 1086.53 ± 123.73 Kg/sec 2. The temporal parameters related to the reflexive response of the neck extensors were also affected by fatigue. Onset delay, time to peak and peak to peak values increased from 92.81

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Role of loading on head stability and effective neck stiffness and viscosity

Cited by 45 publications

References 30 publications

Effect of Neck Muscle Strength and Anticipatory Cervical Muscle Activation on the Kinematic Response of the Head to Impulsive Loads

Effect of Neck Muscle Strength and Anticipatory Cervical Muscle Activation on the Kinematic Response of the Head to Impulsive Loads

In Vivo Dynamics of the Musculoskeletal System Cannot Be Adequately Described Using a Stiffness-Damping-Inertia Model

Post fatigue changes in the stability of cervical spine

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