Lower lumbar spine axial rotation is reduced in end-range sagittal postures when compared to a neutral spine posture

Does Overhead Squat Performance Affect the Swing Kinematics and Lumbar Spine Loads during the Golf Downswing?

The performance of the overhead squat may affect the golf swing mechanics associated with golf-related low back pain. This study investigates the difference in lumbar kinematics and joint loads during the golf downswing between golfers with different overhead squat abilities. Based on the performance of the overhead squat test, 21 golfers aged 18 to 30 years were divided into the highest-scoring group (HS, N = 10, 1.61 ± 0.05 cm, and 68.06 ± 13.67 kg) and lowest-scoring group (LS, N = 11, 1.68 ± 0.10 cm, and 75.00 ± 14.37 kg). For data collection, a motion analysis system, two force plates, and TrackMan were used. OpenSim 4.3 software was used to simulate the joint loads for each lumbar joint. An independent t-test was used for statistical analysis. Compared to golfers demonstrating limitations in the overhead squat test, golfers with better performance in the overhead squat test demonstrated significantly greater angular extension displacement on the sagittal plane, smaller lumbar extension angular velocity, and smaller L4-S1 joint shear force. Consequently, the overhead squat test is a useful index to reflect lumbar kinematics and joint loading patterns during the downswing and provides a good training guide reference for reducing the risk of a golf-related lower back injury.

Contribution of Trunk Rotation and Abdominal Muscles to Sprint Kayak Performance

Over the past two decades the importance of trunk contribution to sporting performance has been highlighted through the expanse of literature concerning core stability and strength. However, the role of trunk motion and the abdominal muscles are yet to be established during sprint kayak performance. The purpose of this study was to determine the associations among trunk rotation, kayak velocity, and abdominal muscle activity during on-water sprint kayaking. Eight international paddlers completed five 150 m sprint trials. During each trial peak muscle activation (peak root-mean-squared electromyogram) of the latissimus dorsi, rectus abdominus, external obliques and rectus femoris for ipsilateral (stroke side) and contralateral (opposite side) were recorded as the paddler passed through a 5-m calibrated volume, in conjunction with upper and lower trunk rotation and kayak velocity. Results indicated a significant strong negative relationship between lower trunk rotation and peak velocity (r = -0.684, p < 0.05). Furthermore, a significant strong positive relationship (p < 0.05) with mean velocity was identified for the contralateral rectus abdominus and multiple significant associations between the rectus femoris, rectus abdominus and external obliques during the paddle stroke. Findings indicate that limiting the rotation of the lower trunk will increase both the peak and the mean velocity, with the rectus abdominus, external oblique and rectus femoris combining to assist in this process. Training should therefore focus on developing the strength of these muscle groups to enhance performance.

Effect of incremental intensities on the spinal morphology and core muscle activation in competitive cyclists

Cycling is a sport where cyclists predominantly adopt a sitting posture, with the trunk tilted forward. This posture requires a high volume of training and duration in several intensities of effort. This study aims to: 1) evaluate the behaviour of the thoracic and lumbar spine flexion and sacral inclination in the sagittal plane, the thoracic and lumbar spine flexion in the frontal plane, and the trunk torsion in the transverse plane; 2) compare the activation of the core muscles as the intensity of effort increases during an incremental test in cycling, and 3) identify which core muscle has a greater activation in each intensity zone. The spinal posture and the activation of the eight core muscles were evaluated in twelve competitive cyclists during incremental cycling intensities. Thoracic and lumbar spine flexion and sacral inclination statistically increased as the intensity of effort increased (Start < VT1 < VT2 < VO2max). A significant increase in muscle activation was observed in all core muscles evaluated as the intensity increased. The rectus abdominis showed statistically significant greater muscle activation than the other core muscles evaluated. In conclusion, as the intensity of effort in cycling increases, cyclists significantly increase the thoracic and lumbar spine flexion, the sacral inclination in the sagittal plane, the thoracic and lumbar spine flexion in the frontal plane, trunk rotation in the transverse plane, as well as the activation of the core muscles.

Examining the Peer-Reviewed Published Literature Regarding Low Back Pain in Rowing: A Scoping Review

Background

Low back pain (LBP) is highly prevalent in the rowing population. The body of existing research variously investigates risk factors, prevention, and treatment methods.

Purpose

The purpose of this scoping review was to explore the breadth and depth of the LBP literature in rowing and to identify areas for future research.

Study Design

Scoping review.

Methods

PubMed, Ebsco and ScienceDirect were searched from inception to November 1, 2020. Only published, peer-reviewed, primary, and secondary data pertaining to LBP in rowing were included for this study. Arksey and O'Malley's framework for guided data synthesis was used. Reporting quality of a subsection of the data was assessed using the STROBE tool.

Results

Following the removal of duplicates and abstract screening, a set of 78 studies were included and divided into the following categories: epidemiology, biomechanics, biopsychosocial, and miscellaneous. The incidence and prevalence of LBP in rowers were well mapped. The biomechanical literature covered a wide range of investigations with limited cohesion. Significant risk factors for LBP in rowers included back pain history and prolonged ergometer use.

Conclusion

A lack of consistent definitions within the studies caused fragmentation of the literature. There was good evidence for prolonged ergometer use and history of LBP to constitute risk factors and this may assist future LBP preventative action. Methodological issues such as small sample size and barriers to injury reporting increased heterogeneity and decreased data quality. Further exploration is required to determine the mechanism of LBP in rowers through research with larger samples.

Is Golf a Contact Sport? Protection of the Spine and Return to Play After Lumbar Surgery

STUDY DESIGN

Narrative review.

OBJECTIVE

To address the gap in the literature on specific return to play protocols and rehabilitation regimens for golfers undergoing lumbar spine surgery with a high impact swing.

METHODS

This review did not involve patient care or any clinical prospective or retrospective review of patient information and thus did not warrant institutional review board approval. The available literature of PubMed, Medline, and OVID was utilized to review the existing literature.

RESULTS

Studies have shown that the forces through the lumbar spine in the modern-era golf swing are like other contact sports. Methods of protecting the lumbar spine include proper swing mechanics, abdominal and paraspinal musculature strengthening and flexibility as well as physical fitness. There are a variety of treatment options available to treat lumbar spine pathology each with a different return to play recommendations from doctors in the field.

CONCLUSIONS

With the introduction of a high impact, modern-era swing to the game of golf, the pathology is seen in the lumbar spine of both young, old, professional, and amateur golfers with low back pain are similar to other athletes in contact sports. Surgery is effective in returning athletes to a similar level of play even though no protocols exist for an effective and safe return. There have been many studies conducted to determine appropriate treatment and return to play for these injuries, but there is a gap in the literature on specific return to play protocols and rehabilitation regimens for golfers undergoing lumbar spine surgery with a high impact swing. As return to competitive play is important, especially with professional golfers, studies combining the use of swing mechanics changes, rehabilitation regimens and the type of surgery performed would be able to provide some insight into this topic now that golf may begin to be considered a contact sport.

Lumbar Bone Mineral Adaptation: The Effect of Fast Bowling Technique in Adolescent Cricketers

INTRODUCTION

Localised bone mineral density (BMD) adaptation of the lumbar spine, particularly on the contralateral side to the bowling arm, has been observed in elite male cricket fast bowlers. No study has investigated this in adolescents, or the role of fast bowling technique on lumbar BMD adaptation. This study aims to investigate lumbar BMD adaptation in adolescent cricket fast bowlers, and its relationship with fast bowling technique.

METHODS

39 adolescent fast bowlers underwent antero-posterior DXA scan of their lumbar spine. Hip, lumbopelvic and thoracolumbar joint kinematics, and vertical ground reaction kinetics were determined using 3D motion capture and force plates. Significant partial (covariate: fat free mass) and bivariate correlations of the technique parameters with whole lumbar (L1-L4) BMD and BMD asymmetry (L3 and L4) were advanced as candidate variables for multiple stepwise linear regression.

RESULTS

Adolescent fast bowlers demonstrated high lumbar Z-Scores (+1.0; 95%CI: 0.7 - 1.4) and significantly greater BMD on the contralateral side of L3 (9.0%; 95%CI: 5.8 - 12.1%) and L4 (8.2%; 95%CI: 4.9 - 11.5%). Maximum contralateral thoracolumbar rotation and maximum ipsilateral lumbopelvic rotation in the period between back foot contact (BFC) and ball release (BR), as well as contralateral pelvic drop at front foot contact (FFC), were identified as predictors of L1-L4 BMD, explaining 65% of the variation. Maximum ipsilateral lumbopelvic rotation between BFC and BR, as well as ipsilateral lumbopelvic rotation and contralateral thoracolumbar side flexion at BR, were predictors of lumbar asymmetry within L3 and L4.

CONCLUSION

Thoracolumbar and lumbopelvic motion are implicated in the aetiology of the unique lumbar bone adaptation observed in fast bowlers whereas vertical ground reaction force, independent of body mass, was not. This may further implicate the osteogenic potential of torsional rather than impact loading in exercise-induced adaptation.

Cervical flexion relaxation phenomenon in patients with and without non-specific chronic neck pain

BACKGROUND

The cervical flexion relaxation phenomenon (FRP) is a myoelectric silence of neck extensor muscles which occurs after a certain degree of flexion. Impaired flexion relaxation can impose the vertebral structures to excessive loading resulting from the persistence of muscular contraction.

OBJECTIVE

This study aimed to investigate the incidence or absence of FRP in cervical erector spinae (CES) and upper trapezius muscles in patients with chronic neck pain (CNP).

METHODS

Twenty-five patients with CNP and 25 healthy volunteers were recruited. They accomplished cervical flexion and extension from a neutral position in four phases in the sitting position. The surface electromyography activity of both CES and upper trapezius muscles was recorded in each phase. Cervical flexion and extension movements were simultaneously measured using an electrogoniometer.

RESULTS

FRP in CES was observed in 84% and 36% of healthy subjects and CNP patients, respectively. Flexion relaxation ratio (FRR) in CES was lower in CNP patients than in healthy subjects (mean diff = 1.33; 95% CI: 0.75-1.91) (P< 0.001). Only in CNP patients, FRR in right erector spinea was significantly higher than that in the left erector spinea (P= 0.04).

CONCLUSIONS

FRP incidence in CNP patients was less than in healthy subjects. Moreover, this phenomenon begins later in CNP patients than in healthy subjects indicating prolonged activity of CES muscles during flexion in the CNP group. The difference between FRR in the right and left sides of erector spinea muscles can result in CNP.

Lumbar Axial Rotation Kinematics in an Upright Sitting and With Forward Bending Positions in Men With Nonspecific Chronic Low Back Pain

STUDY DESIGN

A controlled cross-sectional study.

OBJECTIVE

The aim of this study was to compare the kinematics of lumbar axial rotation while sitting in an upright and forward bending position in men suffering with and without nonspecific chronic low back pain (NSCLBP).

SUMMARY OF BACKGROUND DATA

Lumbar rotation while sitting is an important factor in the mechanism of low back pain. Nevertheless, its kinematics has scarcely been investigated.

METHODS

Range of motion (ROM in), average velocity (AV), maximum velocity (MV), and maximal acceleration (MA) of lumbar rotation while sitting in an upright (UP-sitting) and full forward bending position (FFB-sitting) were examined using an industrial lumbar motion monitor in 50 men (25 with NSCLBP and 25 controls). Pain level and the Rolland Morris questionnaire (RMQ) were also included.

RESULTS

All examined kinematical parameters were significantly lower in men with NSCLBP compared with the controls (↓ROM = 16%-29%; ↓AV = 35%-53%; ↓MV = 3%-46%; ↓MA = 7%-44%) and significantly decreased when moving from UP-sitting to FFB-sitting. In the UP-sitting, the ROM and AV in both groups and the right rotation-MV in the NSCLBP group were always greater during the right rotation compared to the left (NSCLBP = ROM: Δ3.92°, AV: Δ2.74°, MV:Δ3.61°; controls = ROM: Δ3.46°, AV: Δ1.72°). The left rotation-MV was significantly greater compared to the right only in FFB-sitting in the controls (Δ3.03°). In all kinematical parameters in the NSCLBP group, no correlations were found in the visual analogue scale (VAS) levels (4.43 ± 1.47) or RMQ total score (12.32 ± 5.44).

CONCLUSION

The kinematic parameters of lumbar rotation were reduced in men with NSCLBP compared with controls both in an UP-sitting and FFB-sitting. In both groups, NSCLBP and controls, asymmetry in lumbar rotation kinematics was indicated as well as a decrease when moving from UP-sitting to FFB-sitting.

LEVEL OF EVIDENCE

3.

Interaction Between Thoracic Movement and Lumbar Spine Muscle Activation Patterns in Young Adults Asymptomatic for Low Back Pain: A Cross-Sectional Study

OBJECTIVE

The purpose of this study was to investigate the interaction between thoracic movement and lumbar muscle co-contraction when the lumbar spine was held in a relatively neutral posture.

METHODS

Thirty young adults, asymptomatic for back pain, performed 10 trials of upright standing, maximum trunk range of motion, and thoracic movement tasks while lumbar muscle activation was measured. Lumbar co-contraction was calculated, compared between tasks, and correlated to thoracic angles.

RESULTS

Movement tasks typically exhibited greater co-contraction than upright standing. Co-contraction in the lumbar musculature was 67%, 45%, and 55% greater than upright standing for thoracic flex, thoracic bend, and thoracic twist, respectively. Generally, the thoracic movement task demonstrated greater co-contraction than the maximum task in the same direction. Co-contraction was also correlated to thoracic angles in each movement direction.

CONCLUSION

Tasks with thoracic movement and a neutral lumbar spine posture resulted in increases in co-contraction within the lumbar musculature compared with quiet standing and maximum trunk range-of-motion tasks. Findings indicated an interaction between the 2 spine regions, suggesting that thoracic posture should be accounted for during the investigation of lumbar spine mechanics.

Efficacy of Abdominal Control Feedback and Scapula Stabilization Exercises in Participants With Forward Head, Round Shoulder Postures and Neck Movement Impairment

BACKGROUND

Signs and symptoms of impaired function of the musculoskeletal system may be targeted by treating dysfunction located elsewhere.

HYPOTHESIS

Abdominal control feedback and scapular stabilization exercise interventions would result in positive changes in pain intensity, strength, electromyography, and flexion-relaxation phenomena in women with forward head and round shoulder postures and neck movement impairment.

STUDY DESIGN

Pretest-posttest intervention.

LEVEL OF EVIDENCE

Level 1.

METHODS

A total of 135 women (aged 27.23 ± 1.9 years) with forward head and round shoulder postures were randomized to 3 groups. Group 1 received 6-week scapular stabilization exercises with abdominal control feedback (n = 45), group 2 received 6-week scapular stabilization exercises without abdominal control feedback (n = 45), and group 3 received active self-exercise as a control group (n = 45). Posture, pain, proprioception, strength, and electromyography were assessed before and after the interventions.

RESULTS

There were significant between-group differences in pain, proprioception, strength, and electromyography favoring group 1. There were significant within-group changes in posture, pain, proprioception, strength, and electromyography in both groups 1 and 2. No significant change was observed for muscle strength.

CONCLUSION

The addition of abdominal control feedback to the scapular stabilization exercises was shown to be superior to the scapular stabilization exercises alone for decreasing neck pain and restoring proper proprioception, strength, and electromyography in females with forward head and round shoulder postures and neck movement impairment.

CLINICAL RELEVANCE

The addition of abdominal control feedback to scapular stabilization exercises is superior to scapular stabilization exercises alone on the neck for improving electromyography, strength, and function in females with forward head and round shoulder postures and neck movement impairment.

Lumbar axial rotation kinematics in men with non-specific chronic low back pain

BACKGROUND

Lumbar flexion, coupled with rotation, is a dominant factor in the etiology and exacerbation of low back pain. Yet, no study has examined its kinematics in patients with non-specific chronic low back pain (NSCLBP). The aim of the study was to evaluate the lumbar rotation kinematics in neutral standing and with full flexion in men with NSCLBP.

METHODS

ROM, average velocity, maximum velocity and maximal acceleration of lumbar rotation in neutral standing and with full flexion were measured using an industrial lumbar motion monitor in 50 men (25 with NSCLBP and 25 controls). VAS and Rolland Morris questionnaire were also included.

FINDINGS

All examined kinematical parameters were significantly lower in men with NSCLBP compared with controls (↓ROM = 29%-45%; ↓AV = 40%-68%; ↓MV = 25%-50%; ↓MA = 20%-37%). Left rotation manifested smaller kinematic values (except for MA) than right rotation (Δ ROM = 35%; Δ AV = 66%; Δ MV = 19%) in NSCLBP. Most kinematical parameters significantly decreased from neutral standing to standing with flexion (right rotation: ↓ROM = 43%-45%, ↓AV = 38%-45%, ↓MV = 24%-27%, ↓MA for the NSCLBP group = 21%; left rotation: ↓ROM = 25%-38%, ↓AV in the control group: =34%, ↓MV in the control group: =23%, ↓MA in the control group = 25%). No correlations were found between all measured kinematical parameters, VAS and RMQ total score in the NSCLBP group.

INTERPRETATION

The kinematic parameters of lumbar rotation were reduced in men with NSCLBP compared with controls both in neutral standing and with fully forward bending. Most lumbar rotation kinematics decreased from neutral standing to standing with flexion.

Does the new rugby union scrum sequence positively influence the hooker's in situ spinal kinematics?

Background

Scrummaging is unique to rugby union and involves 2 ‘packs’ of 8 players competing to regain ball possession. Intending to serve as a quick and safe method to restart the game, injury prevalence during scrummaging necessitates further evaluation of this environment.

Aims

The aim of this study was to determine the effect of scrummage engagement sequences on spinal kinematics of the hooker. The conditions investigated were: (1) live competitive scrummaging using the new ‘crouch, bind, set’ sequence; (2) live competitive scrummaging using the old ‘crouch touch pause engage’ sequence and (3) training scrummaging using a scrum machine.

Methods

Inertial sensors provided three-dimensional kinematic data across 5 spinal regions. Participants (n=29) were adult, male community club and university-level hookers.

Results

Engagement sequence had no effect on resultant kinematics of any spinal region. Machine scrummaging resulted in lesser magnitudes of motion in the upper spinal regions. Around two-thirds of the total available cervical motion was utilised during live scrummaging.

Conclusions

This study indicates that the most recent laws do not influence the spinal kinematics of the hooker during live scrummaging; however, there may be other benefits from these law changes that fall outside the scope of this investigation.

Repeatability of kinematic and electromyographical measures during standing and trunk motion: how many trials are sufficient?

Previous studies have recommended a minimum of five trials to produce repeatable kinematic and electromyography (EMG) measures during target postures or contraction levels. This study aimed to evaluate the repeatability and reliability of kinematic and EMG measures that are of primary interest in the investigation of trunk movement, and to determine the number of trials required to achieve repeatability and reliability for these measures. Thirty participants performed ten trials of upright standing and maximum trunk ranges-of-motion. Mean (upright standing) and maximum (movement tasks) kinematic and EMG measures were assessed using intraclass correlation coefficients and standard error of measurement, which were used to identify the minimum number of trials for each measure. The repeatability and reliability of the measures were generally high, with 64%, 77%, 85%, and 92% of measures producing repeatable and reliable values with two, three, four, and five trials, respectively. Ten trials were not sufficient for several upright standing angle measures and maximum twist lumbar angles. Further, several abdominal muscles during maximum flexion, as well as the left lower-thoracic erector spinae during maximum twist, required as many as five trials. These measures were typically those with very small amounts of motion, or muscles that did not act in the role of prime mover. These results suggest that as few as two trials may be sufficient for many of the kinematic and EMG measures of primary interest in the investigation of trunk movement, while the collection of four trials should produce repeatable and reliable values for over 80% of measures. These recommendations are intended to provide an acceptable trade-off between repeatable and reliable values and feasibility of the collection protocol.

Axial rotation mechanics in a cadaveric lumbar spine model: a biomechanical analysis

BACKGROUND CONTEXT

Postoperative patient motions are difficult to directly control. Very slow quasistatic motions are intuitively believed to be safer for patients, compared with fast dynamic motions, because the torque on the spine is reduced. Therefore, the outcomes of varying axial rotation (AR) angular loading rate during in vitro testing could expand the understanding of the dynamic behavior and spine response.

PURPOSE

To observe the effects of the loading rate in AR mechanics of lumbar cadaveric spines via in vitro biomechanical testing.

STUDY DESIGN

An in vitro biomechanical study in lumbar cadaveric spines.

METHODS

Fifteen lumbar cadaveric segments (L1-S1) were tested with varying loading frequencies of AR. Five different frequencies were normalized with the base line frequency (0.125 Hz n=15) in this analysis: 0.05 Hz (n=6), 0.166 Hz (n=6), 0.2 Hz (n=10), 0.25 Hz (n=10), and 0.4 Hz (n=8).

RESULTS

The lowest frequency (0.05 Hz) revealed significant differences (p<.05) for all parameters (torque, passive angular velocity, axial velocity [AV], axial reaction force [RF], and energy loss [EL]) with respect to all other frequencies. Significant differences (p<.05) were observed in the following: torque (0.4 Hz with respect to 0.2 Hz and 0.25 Hz), passive sagittal angular velocity (SAV) (0.4 Hz with respect to all other frequencies; 0.166 Hz with respect to 0.25 Hz), axial linear velocity (0.4 Hz with respect to all other frequencies), and RF (0.4 Hz with respect to 0.2 Hz and 0.25 Hz). Strong correlations (R2>0.75, p<.05) were observed between RF with intradiscal pressure (IDP) and AR angular displacement with IDP. Intradiscal pressure (p<.05) was significantly larger in 0.2 Hz in comparison with 0.125 Hz.

CONCLUSIONS

Evidences suggest that measurements at very small frequencies (0.05 Hz) of torque, SAV, AV, RF, and EL are significantly reduced when compared with higher frequencies (0.166 Hz, 0.2 Hz, 0.25 Hz, and 0.4 Hz). Higher frequencies increase torque, RF, passive SAV, and AV. Higher frequencies induce a greater IDP in comparison with lower frequencies.

Lumbar loading in the elite adolescent tennis serve: link to low back pain

PURPOSE

This study aimed to quantify and compare lumbar region kinetics in kick and flat serves performed by elite, adolescent male players with and without a history of low back pain (LBP). Lumbar region kinematics, as well as racquet velocity and the position of the ball at impact, was described to facilitate kinetic data interpretation.

METHODS

Twenty Tennis Australia adolescent male players participated; 7 had a history of disabling LBP and confirmed L4/L5 injury and 13 were age-, height-, mass-, and performance-matched controls. The VICON motion analysis system was used to record racquet, upper and lower limb, trunk, and lumbar movement during three "flat" and three "kick" serves. A customized mathematical model calculated lumbar region kinetics/kinematics, racquet velocity, and ball position at impact, and these are reported as if all players were right-handed. A series of 2 × 2 mixed-model ANOVA were used to compare between pain/no pain and kick/flat serves.

RESULTS

There was no significant difference in racquet velocity or ball position at impact between pain groups or serve types. The players with LBP reported significantly greater (mean difference = 1.5 N · kg(-1)) peak left lateral force than the control group. The flat serve was associated with significantly greater flexion moments (mean difference = 2.7 N · kg(-1)) than the kick serve.

CONCLUSIONS

The lumbar region undergoes substantial loading during both the kick and the flat tennis serves, including lateral flexion forces approximately eight times those experienced during running. Given that these left lateral flexion forces are significantly greater in players with a history of disabling LBP and occur simultaneous with peak vertical force and extension and right lateral rotations, this may be an important LBP mechanism in this population.

Improving Field Observation of Spinal Posture in Sitting

Observing seated posture is important for ergonomic assessment; proper chair fit and chair adjustment should be considered for the entire context of work demands. Recommending only one seated posture presumes that all seated work has a similar location of visual targets, shoulder reach distances, and support surfaces. The nature of work tasks may influence posture more than does chair adjustment, and field observation of sitting should focus specifically on lumbar spine posture when work may cause forward movement of the torso. I suggest that the position and movement of the pelvis in relation to the torso is a reasonable and important indicator of spinal posture.

Nucleus pulposus deformation in response to rotation at L1-2 and L4-5

BACKGROUND

Spinal rotation couples with lateral flexion as a composite movement. Few data report the in vivo mechanical deformation of the nucleus pulposus following sustained rotation. MRI provides a non-invasive method of examining nucleus pulposus deformation by mapping the hydration signal distribution within the intervertebral disc.

METHODS

T1 weighted coronal and sagittal lumbar images and T2 weighted axial images at L1-2 and L4-5 were obtained from 10 asymptomatic subjects (mean age 29, range: 24-34 years) in sustained flexed and extended positions plus combined positions of left rotation with flexion and extension. Nucleus pulposus deformation was tracked by mapping the change in hydration profiles from coronal and sagittal pixel measurements.

FINDINGS

An average sagittal change in position of 44° (SD 14.5°) from flexion to extension was recorded between L1 and S1 (range: 18°- 60°) resulting in a mean anterior nucleus pulposus deformation of 16% of disc hydration profile (range: 3.5%-19%) in 19/20 discs. When rotation was combined with either flexion or extension, mean coronal deformation was 4.8% (SD-5.1%; range: 0.4%-15%). Lateral nucleus pulposus deformation direction varied in rotation (44% deformed left and 56% deformed right). Intersegmental lateral flexion direction more strongly predicted nucleus pulposus deformation direction with 75% deforming contralaterally.

INTERPRETATION

Nucleus pulposus deformation direction in young subjects was more predictable following sagittal position change than in rotation combined with flexion or extension. Deformation magnitude was reduced in rotated positions. Intersegmental lateral flexion was a stronger predictor of nucleus pulposus deformation direction.

A pilot investigation into the effects of different office chairs on spinal angles

PURPOSE

To investigate the effects of four office chairs on the postural angles of the lumbopelvic and cervical regions.

RESEARCH QUESTION

Which chair(s) produce an "ideal" spinal posture?

METHODS

An experimental same subject design was used involving healthy subjects (n = 14) who conducted a typing task whilst sitting on four different office chairs; two "dynamic" chairs (Vari-Kneeler and Swopper), and two static chairs (Saddle and Standard Office with back removed). Data collection was via digital photogrammetry, measuring pelvic and lumbar angles, neck angle and head tilt which were then analysed within MatLab. A repeated measures ANOVA with Bonferroni corrections for multiple comparisons was conducted.

RESULTS

Statistically significant differences were identified for posterior pelvic tilt and lumbar lordosis between the Vari-Kneeler and Swopper chairs (p = 0.006, p = 0.001) and the Vari-Kneeler and Standard Office chairs (p = 0.000, 0.000); and also for neck angle and head tilt between the Vari-Kneeler and Swopper chairs (p = 0.000, p = 0.000), the Vari-Kneeler and Saddle chairs (p = 0.002, p = 0.001), the Standard Office and Swopper chairs (p = 0.000, p = 0.000), and the Standard Office and Saddle chairs (p = 0.005, p = 0.001). This study confirms a within region association between posterior pelvic tilt and lumbar lordosis, and between neck angle and head tilt. It was noted that an ideal lumbopelvic position does not always result in a corresponding ideal cervical position resulting in a spinal alignment mismatch.

CONCLUSION

In this study, the most appropriate posture for the lumbopelvic region was produced by the Saddle chair and for the cervical region by both the Saddle and Swopper chairs. No chair consistently produced an ideal posture across all regions, although the Saddle chair created the best posture of those chairs studied. Chair selection should be based on individual need.

Comparing lower lumbar kinematics in cyclists with low back pain (flexion pattern) versus asymptomatic controls--field study using a wireless posture monitoring system

The aim of this study was to examine lower lumbar kinematics in cyclists with and without non-specific chronic low back pain (NS-CLBP) during a cross-sectional cycling field study. Although LBP is a common problem among cyclists, studies investigating the causes of LBP during cycling are scarce and are mainly focussed on geometric bike-related variables. Until now no cycling field studies have investigated the relationship between maladaptive lumbar kinematics and LBP during cycling. Eight cyclists with NS-CLBP classified as having a 'Flexion Pattern' (FP) disorder and nine age- and gender-matched asymptomatic cyclists were tested. Subjects performed a 2 h outdoor cycling task on their personal race bike. Lower lumbar kinematics was measured with the BodyGuard™ monitoring system. Pain intensity during and after cycling was measured using a numerical pain rating scale. The NS-CLBP (FP) subjects were significantly more flexed at the lower lumbar spine during cycling compared to healthy controls (p = 0.018), and reported a significant increase in pain over the 2 h of cycling (p < 0.001). One-way repeated measures ANOVA revealed a significant main effect for group (p = 0.035, F = 5.546) which remained just significant when adding saddle angle as a covariate (p = 0.05, F = 4.747). The difference in posture between groups did not change over time. These findings suggest that a subgroup of cyclists with NS-CLBP (FP) demonstrate an underlying maladaptive motor control pattern resulting in greater lower lumbar flexion during cycling which is related to a significant increase in pain.

The effects of spinal posture and pelvic fixation on trunk rotation range of motion

BACKGROUND

Axial rotation of the trunk is important to many vocational tasks and activities of daily living, and may be associated with back injuries. The influence of spinal postures on trunk rotation appears conflicting. This study investigated the influence of forward trunk inclination, spinal posture and pelvic fixation on maximum trunk rotation.

METHODS

Twenty male participants were assessed using an optoelectronic motion-analysis system to track trunk movement during maximal trunk rotations in different spinal positions within the sagittal plane. A repeated-measures multivariate analysis of variance investigated the effects of forward trunk inclination, spinal posture and pelvic fixation on trunk and pelvic rotation. Test-retest reliability was determined using interclass correlation coefficients and standard error of measurement.

FINDINGS

Forward trunk inclination at 45° yielded a 19% (6.2°; P<0.001) increase in trunk rotation and a 40% (25.5°; P<0.001) decrease in pelvic rotation when compared to standing. When flexing and extending the spine at a forward trunk inclination of 45° there was a 5% (1.9°; P<0.01) and a 4% (1.6°; P<0.05) decrease in trunk rotation. Fixing the pelvis increased the trunk rotation by up to 9% (3.3°; P<0.001).

INTERPRETATION

Inclining the trunk forward and maintaining a neutral spine maximised trunk rotation range of motion (RoM). This has implications for educational programmes intended to maximise sporting performance. Within the clinical setting, unrestricted observation of trunk rotations is considered more appropriate as it may benefit the clinician in determining possible detrimental relative flexibilities that may exist within the body.

Differences in spinopelvic kinematics in sweep and scull ergometer rowing

OBJECTIVE

The spinopelvic kinematics of sweep and scull have yet to be investigated, despite evidence suggesting that sweep rowing may be provocative for low back pain (LBP). The aim of this study was to determine whether differences existed in spinopelvic kinematics in high-level rowers without LBP in sweep and scull ergometer rowing.

DESIGN

Repeated measures study.

SETTING

Institute of Sport Laboratory.

PARTICIPANTS

Ten high-level rowers.

INTERVENTIONS

Kinematics of the pelvis, lower lumbar, upper lumbar, and lower thoracic regions during the drive phase of the rowing stroke were measured while rowing on an interchangeable sweep/scull ergometer.

MAIN OUTCOME MEASURES

Total and segmental spinopelvic kinematics.

RESULTS

Sweep rowing showed greater lateral bend (P < 0.05) throughout the stroke, which was predominately due to movement of the upper lumbar and lower thoracic regions. Furthermore, sweep rowing displayed a greater magnitude (P < 0.05) of axial rotation at the catch (created at the pelvis). Both sweep and scull rowing showed values close to end range flexion for the lower lumbar spine at the catch and early drive phases. No difference (P > 0.05) was evident in lateral bend or axial rotation values for the lower lumbar region.

CONCLUSIONS

Some differences exist in spinopelvic kinematics between sweep and scull ergometer rowing. However, it may be speculated that the lack of differences in lateral bend and axial rotation at the lower lumbar spine in sweep rowing may represent an adaptive and protective approach of experienced rowers. This may be the focus of future research studies.