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Venkata K. Gade and Sara E. Wilson

Proprioception plays an important role in appropriate sensation of spine position, movement, and stability. Previous research has demonstrated that position sense error in the lumbar spine is increased in flexed postures. This study investigated the change in position sense as a function of altered trunk flexion and moment loading independently. Reposition sense of lumbar angle in 17 subjects was assessed. Subjects were trained to assume specified lumbar angles using visual feedback. The ability of the subjects to reproduce this curvature without feedback was then assessed. This procedure was repeated for different torso flexion and moment loading conditions. These measurements demonstrated that position sense error increased significantly with the trunk flexion (40%, p < .05) but did not increase with moment load (p = .13). This increased error with flexion suggests a loss in the ability to appropriately sense and therefore control lumbar posture in flexed tasks. This loss in proprioceptive sense could lead to more variable lifting coordination and a loss in dynamic stability that could increase low back injury risk. This research suggests that it is advisable to avoid work in flexed postures.

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Dean C. Hay, Mark P. Wachowiak and Ryan B. Graham

Advances in time-frequency analysis can provide new insights into the important, yet complex relationship between muscle activation (ie, electromyography [EMG]) and motion during dynamic tasks. We use wavelet coherence to compare a fundamental cyclical movement (lumbar spine flexion and extension) to the surface EMG linear envelope of 2 trunk muscles (lumbar erector spinae and internal oblique). Both muscles cohere to the spine kinematics at the main cyclic frequency, but lumbar erector spinae exhibits significantly greater coherence than internal oblique to kinematics at 0.25, 0.5, and 1.0 Hz. Coherence phase plots of the 2 muscles exhibit different characteristics. The lumbar erector spinae precedes trunk extension at 0.25 Hz, whereas internal oblique is in phase with spine kinematics. These differences may be due to their proposed contrasting functions as a primary spine mover (lumbar erector spinae) versus a spine stabilizer (internal oblique). We believe that this method will be useful in evaluating how a variety of factors (eg, pain, dysfunction, pathology, fatigue) affect the relationship between muscles’ motor inputs (ie, activation measured using EMG) and outputs (ie, the resulting joint motion patterns).

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Catherine Mason and Matt Greig

experiencing pain, and for 76% of riders this pain was in the lower back. 3 Kraft et al 4 postulated that the cause of low back pain in riders might be an overuse syndrome of the lumbar spine as a result of the repetitive compressive, torsional, and bending loads absorbed by the rider. 5 The authors used

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Hardeep Singh, Mark Lee, Matthew J. Solomito, Christian Merrill and Carl Nissen

Spondylolysis is an acquired fracture along the bony connection (pars interarticularis) between the superior and articular facets of a vertebral body and most commonly occurs in the lumbar spine. Spondylolisthesis, in which one vertebral body translates in the sagittal plane across the adjacent

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Angélica Ginés-Díaz, María Teresa Martínez-Romero, Antonio Cejudo, Alba Aparicio-Sarmiento and Pilar Sainz de Baranda

The spine, in its sagittal plane, presents a series of physiological curvatures: cervical lordosis constituted by 7 vertebrae (C1–C7), thoracic or dorsal kyphosis constituted by 12 vertebrae (T1–T12), lumbar lordosis formed by 5 vertebrae (L1–L5), sacrum kyphosis formed by 5 vertebrae usually fused

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Mohammad Reza Pourahmadi, Ismail Ebrahimi Takamjani, Shapour Jaberzadeh, Javad Sarrafzadeh, Mohammad Ali Sanjari, Rasool Bagheri and Morteza Taghipour

their function. Therefore, the ability to reliably measure and evaluate lumbar spine motion is essential in elucidating the pathophysiologies of various musculoskeletal disorders, such as LBP. 17 The anatomy and function of the lumbar spine is complex and, therefore, requires a measurement technique

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Mohammadreza Pourahmadi, Hamid Hesarikia, Ali Ghanjal and Alireza Shamsoddini

psychometric properties of the iHandy Level app in measuring lumbar spine lordosis and ROM. Methods Search Strategy This systematic review was planned and reported in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. 11 The following databases were

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Simon Wang and Stuart M. McGill

Spine stability is ensured through isometric coactivation of the torso muscles; however, these same muscles are used cyclically to assist ventilation. Our objective was to investigate this apparent paradoxical role (isometric contraction for stability or rhythmic contraction for ventilation) of some selected torso muscles that are involved in both ventilation and support of the spine. Eight, asymptomatic, male subjects provided data on low back moments, motion, muscle activation, and hand force. These data were input to an anatomically detailed, biologically driven model from which spine load and a lumbar spine stability index was obtained. Results revealed that subjects entrained their torso stabilization muscles to breathe during demanding ventilation tasks. Increases in lung volume and back extensor muscle activation coincided with increases in spine stability, whereas declines in spine stability were observed during periods of low lung inflation volume and simultaneously low levels of torso muscle activation. As a case study, aberrant ventilation motor patterns (poor muscle entrainment), seen in one subject, compromised spine stability. Those interested in rehabilitation of patients with lung compromise and concomitant back troubles would be assisted with knowledge of the mechanical links between ventilation during tasks that impose spine loading.

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Yuichiro Okushima, Nobutoshi Yamazaki, Morio Matsumoto, Kazuhiro Chiba, Takeo Nagura and Yoshiaki Toyama

A biomechanical study of lateral translation in lumbar spine with human cadavers was performed in order to explore the direction of the force increasing lateral translation and the contributions of discs and facet joints to lateral translation. Whole lumbar spines from 12 fresh cadavers were attached to a specially designed loading apparatus whose five cables simulated the muscles of the trunk without restricting natural movement. Three-dimensional positions of each vertebra were recorded with position-sensitive detectors. Force in the anterolateral direction increased the lateral translation more than force in the posterolateral direction. Lateral translation was increased to a significantly greater extent when the facet joints were removed than when the discs were removed at L4-5 at the levels of shear loading applied in this study.

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Matt Greig and Philip Nagy

Context:

Epidemiological studies highlight a prevalence of lumbar vertebrae injuries in cricket fast bowlers, with governing bodies implementing rules to reduce exposure. Analysis typically requires complex and laboratory-based biomechanical analyses, lacking ecological validity. Developments in GPS microtechnologies facilitate on-field measures of mechanical intensity, facilitating screening toward prevention and rehabilitation.

Objective:

To examine the efficacy of using GPS-mounted triaxial accelerometers to quantify accumulated body load and to investigate the effect of GPS-unit placement in relation to epidemiological observations.

Design:

Repeated measures, field-based.

Setting:

Regulation cricket pitch.

Participants:

10 male injury-free participants recruited from a cricket academy (18.1 ± 0.6 y).

Intervention:

Each participant was fitted with 2 GPS units placed at the cervicothoracic and lumbar spines to measure triaxial acceleration (100 Hz). Participants were instructed to deliver a 7-over spell of fast bowling, as dictated by governing-body guidelines.

Main Outcome Measures:

Triaxial total accumulated body and the relative uniaxial contributions were calculated for each over.

Results:

There was no significant main effect for overs bowled, in either total load or the triaxial contributions to total load. This finding suggests no cumulative fatigue effect across the 10-over spell. However, there was a significant main effect for GPS-unit location, with the lumbar unit exposed to significantly greater load than the cervicothoracic unit in each of the triaxial planes.

Conclusions:

There was no evidence to suggest that accumulated load significantly increased as a result of spell duration. In this respect the governing-body guidelines for this age group can be considered safe, or potentially even conservative. However, the observation of higher body load at the lumbar spine than at the cervicothoracic spine supports epidemiological observations of injury incidence. GPS microtechnologies might therefore be considered in screening and monitoring of players toward injury prevention and/or during rehabilitation.