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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 x 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~') peak left lateral force than the control group. The flat serve was associated with significantly greater flexion moments (mean difference = 2.7 Nkg~ ') 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. [ABSTRACT FROM AUTHOR]

Objectives: Prevention of occupational low back pain (LBP) in nurses is a research priority. Recent research suggests intervening before commencing nursing employment is ideal; however, identification of modifiable risk factors is required. The objective of this study was to investigate modifiable personal characteristics that predicted new-onset LBP in nursing students., Methods: This prospective study was conducted on female nursing students (n=117) without LBP at baseline to predict new-onset LBP (an episode of significant LBP during the follow-up period). At the 12-month follow-up, participants with (n=31) and without new-onset LBP (n=76) were compared across baseline social or lifestyle, psychologic (distress, back pain beliefs, coping strategies, and catastrophising), and physical (spinal postures and spinal kinematics in functional tasks, leg and back muscle endurance, spinal repositioning error, and cardiovascular fitness) characteristics., Results: Participants response rate at follow-up was excellent (91%). After controlling for earlier LBP, age, and BMI, regression analysis showed that modifiable social or lifestyle, psychologic and physical characteristics (namely, smoking, increased physical activity, higher stress, reduced back muscle endurance, greater posterior pelvic rotation in slump sitting, and more accurate spinal repositioning in sitting) were significant and independent predictors of new-onset LBP at follow-up. Inclusion of these factors in multivariate logistic regression analysis, with significant new-onset LBP as the outcome, resulted in a substantial model R of 0.45., Discussion: Modifiable personal characteristics across multiple domains are associated with new-onset LBP in female nursing students. These findings may have implications for the development of prevention and management interventions for LBP in nurses.

Objectives: The study objectives were (1) to determine if adolescent back pain is related to carer back pain; and (2) to examine whether other carer and family factors accounted for any such relationship., Methods: Back pain experience was collected independently from 1608 fourteen-year-old adolescents and their care givers by questionnaire. Measures of back pain impact on carers were also collected (modified activities, missed work, sought professional help, took medication). Other carer factors examined were age, sex, smoking habits, depression, anxiety, and stress. Familial factors examined included income, stressful events, and family functioning. Odds ratios were calculated to describe familial associations with multivariate modeling used to examine the influence of other carer and family factors., Results: Lifetime prevalence of back pain was 46.5% for adolescents and 72% for their carers. Having a carer with back pain increased the risk of back pain for adolescents, and this was magnified if both carers had back pain (odds ratio 1.61). Adolescent back pain was not associated with primary carer age, sex, depression, anxiety, or stress but was related to family stressful events. However, these other factors did not diminish the association between carer back pain and adolescent back pain., Discussion: Carer experience of back pain is clearly associated with adolescent experience of back pain. Although other carer and family factors are also associated, the carer's back pain experience is not a surrogate measure of these other factors suggesting other genetic and behavioral mechanisms may be important for adolescent back pain development.

Study Design: A cross-sectional comparative study between healthy controls and two subgroups of nonspecific chronic low back pain (LBP) patients., Objectives: To determine differences in trunk muscle activation during usual unsupported sitting., Summary of Background Data: Patients with LBP commonly report exacerbation of pain on sitting. Little evidence exists to confirm that subgroups of patients with nonspecific chronic LBP patients use different motor patterns in sitting than pain-free controls., Methods: A total of 34 pain-free and 33 nonspecific chronic LBP subjects were recruited. Two blinded clinicians classified nonspecific chronic LBP patients into two subgroups (active extension pattern and flexion pattern). Surface electromyography (sEMG) was recorded from five trunk muscles during subjects' unsupported "usual" and "slumped" sitting., Results: No differences in trunk muscle activity were observed between healthy controls and nonspecific chronic LBP groups for usual sitting. When the classification system was applied, differences were identified. Compared with no-LBP controls, the active extension pattern group presented with higher levels of cocontraction of superficial fibers of lumbar multifidus (12%), iliocostalis lumborum pars thoracis (36%) and transverse fibers of internal oblique (43%). while the flexion pattern group showed a trend toward lower activation patterns (lumbar multifidus, -7%; iliocostalis lumborum pars thoracis, -6%, and transverse fibers of internal oblique, -5%). The flexion relaxation ratio of the back muscles was lower for nonspecific chronic LBP (superficial lumbar multifidus: t = 4.5; P < 0.001 and iliocostalis lumborum pars thoracis:t = 2.7; P < 0.001), suggesting a lack of flexion relaxation for the nonspecific chronic LBP., Conclusion: Subclassifying nonspecific chronic LBP patients revealed clear differences in sEMG activity during sitting between pain-free subjects and subgroups of nonspecific chronic LBP patients.

Study Design: A comparative study., Objectives: To investigate sitting postures of asymptomatic individuals and nonspecific chronic low back pain (NS-CLBP) patients (pooled and subclassified) and evaluate the importance of subclassification., Summary of Background: Currently, little evidence exists to support the hypothesis that CLBP patients sit differently from pain-free controls. Although classifying NS-CLBP patients into homogeneous subgroups has been previously emphasized, no attempts have been made to consider such groupings when examining seated posture., Methods: Three angles (sacral tilt, lower lumbar, and upper lumbar) were measured during "usual" and "slumped" sitting in 33 NS-CLBP patients and 34 asymptomatic subjects using an electromagnetic measurement device. Before testing, NS-CLBP patients were subclassified by two blinded clinicians. Twenty patients were classified with a flexion motor control impairment and 13 with an active extension motor control impairment., Results: No differences were found between control and NS-CLBP (pooled) patients during usual sitting. In contrast, analyses based on subclassification revealed that patients classified with an active extension pattern sat more lordotic at the symptomatic lower lumbar spine, whereas patients with a flexion pattern sat more kyphotic, when compared with healthy controls (F = 19.7; df1 = 2, df2 = 63, P < 0.001). Further, NS-CLBP patients had less ability to change their posture when asked to slump from usual sitting (t = 4.2, df = 65; P < 0.001)., Conclusions: Differences in usual sitting posture were only revealed when NS-CLBP patients were subclassified. This highlights the importance of subclassifying NS-CLBP patients.