Martin C. Normand

Postural development in school children: a cross-sectional study.

BackgroundLittle information on quantitative sagittal plane postural alignment and evolution in children exists. The objectives of this study are to document the evolution of upright, static, sagittal posture in children and to identify possible critical phases of postural evolution (maturation).MethodsA total of 1084 children (aged 4–12 years) received a sagittal postural evaluation with the Biotonix postural analysis system. Data were retrieved from the Biotonix internet database. Children were stratified and analyzed by years of age with n = 36 in the youngest age group (4 years) and n = 184 in the oldest age group (12 years). Children were analyzed in the neutral upright posture. Variables measured were sagittal translation distances in millimeters of: the knee relative to the tarsal joint, pelvis relative to the tarsal joint, shoulder relative to the tarsal joint, and head relative to the tarsal joint. A two-way factorial ANOVA was used to test for age and gender effects on posture, while polynomial trend analyses were used to test for increased postural displacements with years of age.ResultsTwo-way ANOVA yielded a significant main effect of age for all 4 sagittal postural variables and gender for all variables except head translation. No age × gender interaction was found. Polynomial trend analyses showed a significant linear association between child age and all four postural variables: anterior head translation (p < 0.001), anterior shoulder translation (p < 0.001), anterior pelvic translation (p < 0.001), anterior knee translation (p < 0.001). Between the ages of 11 and 12 years, for anterior knee translation, T-test post hoc analysis revealed only one significant rough break in the continuity of the age related trend.ConclusionA significant linear trend for increasing sagittal plane postural translations of the head, thorax, pelvis, and knee was found as children age from 4 years to 12 years. These postural translations provide preliminary normative data for the alignment of a childs sagittal plane posture.

Kinetic analysis of expertise in spinal manipulative therapy using an instrumented manikin

OBJECTIVE The goals of this study were to measure the kinetic profile of thrust in different groups of subjects with various levels of expertise and to quantify general coordination while performing thoracic spine manipulation. PARTICIPANTS A total of 43 students and chiropractors from the Chiropractic Department of the Université du Québec à Trois-Rivières participated in this study. METHODS Participants were asked to complete ten consecutive thoracic spine manipulations on an instrumented manikin. Peak force, preload force, time to peak force, time to peak force variability, peak force variability, rate of force production and unloading time were compared between groups. Hand-body delay obtained by calculating the temporal lag between the onset of unloading and the onset of peak force application was also compared between groups. RESULTS No group difference was observed for the peak force, peak force variability and preload force variables. However, group differences were present for variables like time to peak force, time to peak force variability, rate of force production, unloading time and hand-body delay. CONCLUSION This study demonstrates clear differences between groups of subjects with different levels of expertise in thoracic spine manipulation. This study also demonstrates the usefulness of a simple, instrumented manikin to analyze spinal manipulation and identify important parameters related to expertise.

Augmented soft tissue mobilization vs natural history in the treatment of lateral epicondylitis: a pilot study.

OBJECTIVE The purpose of this study was to evaluate the effect of augmented soft tissue mobilization (ASTM) on the treatment of lateral epicondylitis. METHODS This randomized clinical study assessed 27 subjects (12 men and 15 women) with lateral epicondylitis and were divided randomly into 2 groups. The experimental group (n = 15) received ASTM twice a week for 5 weeks. The subjects of the control group (n = 12) received advice on the natural evolution of lateral epicondylitis, computer ergonomics, and stretching exercises. Patient-rated outcome was assessed at baseline and after 6 weeks and 3 months using a visual analog scale and the Patient-Rated Tennis Elbow Evaluation. The function was assessed using the pain-free grip strength at baseline and after 6 weeks. RESULTS Both groups showed improvements in pain-free grip strength, visual analog scale, and Patient-Rated Tennis Elbow Evaluation. Sample size for larger future randomized clinical trial was 116 participants. CONCLUSION A larger study investigating the same hypothesis is warranted to detect difference in the effects of these treatments strategies. The study design is feasible, and minor improvements will help to minimize the potential bias.

Cross-cultural Adaptation of the Patient-rated Tennis Elbow Evaluation to Canadian French

INTRODUCTION No questionnaire is available to evaluate disability levels in French-speaking patients suffering from tennis elbow. PURPOSE OF THE STUDY To perform a cross-cultural adaptation of the English version of the Patient-rated Tennis Elbow Evaluation (PRTEE) into Canadian French. METHODS The PRTEE was cross-culturally adapted to Canadian French according to well-established guidelines. Thirty-two patients with tennis elbow completed the prefinal version of the PRTEE. The construct validity, longitudinal validity, and responsiveness were assessed through comparisons with the Visual Analog Scale (VAS) measuring pain and the pain-free grip (PFG) at baseline, six weeks and three months. The internal consistency was assessed by Cronbachs alpha and the item-total correlations. RESULTS The adaptation process resolved the discrepancy between the forward and back translation. The scores of PRTEE were adequately distributed without floor or ceiling effect. Item completion was good. The correlation between the PRTEE and the VAS was moderate to high (r=0.64-0.77) and statistically significant. There was also a low but significant correlation between the PRTEE and PFG (r=-0.38 to -0.48). For the longitudinal construct validity, the correlation with the VAS was moderate to high and statistically significant (r=0.68 and 0.88, p<0.01). The effect size (0.8; 1.0) and the standardized response mean (0.9; 1.0) were high and at least as good as the other outcomes. Internal consistency of the total score was high (Cronbach alpha=0.93) and item-total correlations were substantial for all items (0.58-0.85). CONCLUSIONS This study supports linguistic and conceptual equivalence of our Canadian French version. Because this version of the PRTEE demonstrated good acceptability, construct validity, internal consistency, and responsiveness, it may be used in both research and clinical setting. LEVEL OF EVIDENCE N/A.

UPRIGHT STATIC PELVIC POSTURE AS ROTATIONS AND TRANSLATIONS IN 3-DIMENSIONAL FROM THREE 2-DIMENSIONAL DIGITAL IMAGES : VALIDATION OF A COMPUTERIZED ANALYSIS

PURPOSE The aim of this study was to determine the accuracy in measuring the pelvic orientations of a phantom model using the PosturePrint method. METHODS In the Université du Québec à Trois-Rivières biomechanics laboratory, Trois-Rivières, Quebec, Canada, a mannequin was fixed on a rotating platform. For a set of 3 photographs (left lateral, anterior to posterior, right lateral) of each position, the mannequin pelvis was placed in 68 different postures on a stand, 61 cm from a wall, in front of a digital camera. The camera was at 83.8 cm in height and at 3.35 m from a calibrated wall grid. Mannequin postures were in 5 degrees of freedom: lateral translation (Tx), lateral flexion (Rz), axial rotation (Ry), flexion-extension (Rx), and anterior-posterior translation (Tz). Average errors were the differences of the positioned postures to the PosturePrint computed values. RESULTS Mean and SD of computational errors for rotation displacements were Rx = 0.5 degrees +/- 0.8 degrees , Ry = 1.3 degrees +/- 0.8 degrees , and Rz = 0.5 degrees +/- 0.3 degrees , and for translation, Tz = 1.2 +/- 0.6 mm and Tx = 0.9 +/- 0.5 mm. CONCLUSIONS The PosturePrint system allowed for accurate postural measurement of rotations and translations of a mannequin pelvis. The next step in evaluation of this product would be a reliability study on human subjects.

The Effects of Vibration and Muscle Fatigue on Trunk Sensorimotor Control in Low Back Pain Patients

Introduction Changes in sensorimotor function and increased trunk muscle fatigability have been identified in patients with chronic low back pain (cLBP). This study assessed the control of trunk force production in conditions with and without local erector spinae muscle vibration and evaluated the influence of muscle fatigue on trunk sensorimotor control. Methods Twenty non-specific cLBP patients and 20 healthy participants were asked to perform submaximal isometric trunk extension torque with and without local vibration stimulation, before and after a trunk extensor muscle fatigue protocol. Constant error (CE), variable error (VE) as well as absolute error (AE) in peak torque were computed and compared across conditions. Trunk extensor muscle activation during isometric contractions and during the fatigue protocol was measured using surface electromyography (sEMG). Results Force reproduction accuracy of the trunk was significantly lower in the patient group (CE = 9.81 ± 2.23 Nm; AE = 18.16 ± 3.97 Nm) than in healthy participants (CE = 4.44 ± 1.68 Nm; AE = 12.23 ± 2.44 Nm). Local erector spinae vibration induced a significant reduction in CE (4.33 ± 2.14 Nm) and AE (13.71 ± 3.45 Nm) mean scores in the patient group. Healthy participants conversely showed a significant increase in CE (8.17 ± 2.10 Nm) and AE (16.29 ± 2.82 Nm) mean scores under vibration conditions. The fatigue protocol induced erector spinae muscle fatigue as illustrated by a significant decrease in sEMG median time-frequency slopes. Following the fatigue protocol, patients with cLBP showed significant decrease in sEMG root mean square activity at L4-5 level and responded in similar manner with and without vibration stimulation in regard to CE mean scores. Conclusions Patients with cLBP have a less accurate force reproduction sense than healthy participants. Local muscle vibration led to significant trunk neuromuscular control improvements in the cLBP patients before and after a muscle fatigue protocol. Muscle vibration stimulation during motor control exercises is likely to influence motor adaptation and could be considered in the treatment of cLBP. Further work is needed to clearly identify at what levels of the sensorimotor system these gains are achievable.

Sensorimotor control during peripheral muscle vibration: an experimental study.

OBJECTIVE The aims of this study were to determine whether the application of vibration on a postural lower limb muscle altered the sensorimotor control of its joint as measured by isometric force production parameters and to compare present findings with previous work conducted on trunk muscle. METHODS Twenty healthy adults were asked to reproduce submaximal isometric plantar flexion under 3 different conditions: no vibration and vibration frequencies of 30 and 80 Hz on the soleus muscle. Time to peak torque, variable error, as well as constant error and absolute error in peak torque were calculated and compared across conditions. RESULTS Under vibration, participants were significantly less accurate in the force reproduction task, as they mainly undershot the target torque. Applying an 80-Hz vibration resulted in a significantly higher negative constant error than lower-frequency vibration (30 Hz) or no-vibration condition. Decreases in isometric force production accuracy under vibration influence were also observed in a previous study conducted on trunk muscle. However, no difference in constant error was found between 30- and 80-Hz vibration conditions. CONCLUSION The results suggest that acute soleus muscle vibration interferes with plantar flexion torque generation by distorting proprioceptive information, leading to decreases in accuracy of a force reproduction task. Similar results in an isometric trunk extension force reproduction task were found with vibration applied on erector spinae muscle. However, high-frequency vibration applied on soleus muscle elicited higher force reproduction errors than low-frequency stimulation.