The effect of backpack load on trunk kinematics of imitated pathological gait: a case study

Background: It is well documented that loaded backpacks affect the biomechanics of gait in both children and adults. Minimal information is available with regard to the effects of backpacks on the biomechanics of gait in individuals with clinical gait abnormalities, such as those seen in cerebral palsy. Healthy, non-clinical populations can be taught how to ‘imitate’ typical gait abnormalities in order to study various experimental interventions without enlisting clinical patients. The objective of this study was to determine the acute effect of backpack load on kinematics of the trunk during typical and imitated pathological gait. Methods: COVID 19 restrictions precluded the use of multiple subjects as originally planned, therefore in response to those limitations only one healthy female (25 yrs) performed two trials each of 4 gait styles (typical, crouch, toe, and jump gait), under unloaded and backpack-loaded conditions. Trials were recorded and digitized using a 12-camera motion analysis system. The loaded conditions utilized a student backpack weighted at 20% of the participant’s body weight (11.8 kg) using various sized small weights. Kinematics of the trunk including mean lateral trunk tilt, mean trunk inclination and mean anterior-posterior pelvic tilt, along with select spatio-temporal variables, were compared across loading conditions and among each gait type. Results: The kinematic variables of trunk tilt and pelvic tilt were exaggerated under the loaded conditions across pathological gait patterns. Double support time increased while single support time decreased. Significance: This case-study investigation was conducted as a hypothesis-generating study for kinematic variables of the trunk under load in populations exhibiting the studied gait patterns. The findings warrant further research in reference to load carriage parameters. Electromyographic testing may be beneficial to add to the current test battery in order to capture additional compensatory muscle actions that may contribute to overall dynamic motor control of the participant. Future research should contribute to better informed carriage practices for individuals with pathological gait patterns seen in cerebral palsy and toe walking

EFFECTS OF BACKPACK TYPE ON KINEMATICS OF THE LOWER BACK DURING WALKING AND JOGGING

Heavy backpacks have been suggested to have a pathogenic role in experience of low back pain among children. We have conducted a repeated-measure study to investigate the backpack-induced changes in lumbo-pelvic coordination of forty gender-balanced college age students when they walked and jogged on a treadmill with two different types of backpacks: normal and ergonomically modified. The backpack-induced changes in lumbo-pelvic coordination were larger when carrying an ergonomically modified vs. a normal backpack as well as when jogging versus walking. The larger changes in lumbo-pelvic coordination when carrying an ergonomically modified backpack were likely due to kinematic restraints imposed by rigidity and enhanced attachments devised in the backpack for increased comfort. Given the role of lower back biomechanics in low back pain, the effects of such larger mechanical abnormalities in the lower back when carrying an ergonomically-modified backpack on risk of low back pain among children requires further investigation

Back to the Future: An Evaluation of Morphological Integration in Kyphosis

Morphological integration refers to the interdependence of two or more phenotypic structures. The morphological integration concept is based on the fact that parts of complex organisms do not vary randomly and instead display degrees of non-independence that are thought to occur from shared genetic or developmental origins, and/or functional demands. Integrated traits may develop, evolve, and be inherited together. One instance of morphological integration can be found between the vertebral column and the skull. Due to the position of the skull resting atop of the vertebral column, posture may influence skull development and overall craniofacial morphology. Morphological integration within or between structures is typically statistically assessed by exploring correlation and covariation patterns among biological structures of interest. In this study, an analysis of morphological integration was carried out by studying covariation of morphometric measures from the vertebral column and craniofacial complex. Age- and sex-matched, de-identified computed tomography images of individuals with kyphosis spinal malformation (n = 15) and controls (n = 19) were acquired from Florida Hospital. It is hypothesized that the sample of individuals with kyphosis will exhibit statistically significant covariance differences relative to the control group for T6 vertebral and midfacial linear distance measurements. Anatomical landmarks were identified on the T6 thoracic vertebrae (n = 6) and the midfacial skeleton (n = 6), and XYZ coordinates were recorded for analysis. A subset of 10 individuals (5 kyphosis, 5 controls) individuals were measured on two occasions to assess reliability and measurement error. An Euclidean Distance Matrix Analysis (EDMA) of morphological integration was carried out on the entire sample by calculating correlation values for paired linear distance measurements (one vertebral and one midfacial) separately for the kyphosis and control samples (n = 225 for each sample). Next, EDMA calculated correlation differences and statistically assessed significance using a non-parametric bootstrap (1,000 resamples) and confidence interval testing (α ≤ 0.10). Only 35 of the 225 (15.56%) correlation differences were statistically significant. Patterns of variation among these significant correlation differences were explored by examining sample directionality of differences, sign patterns, and strengths. The relevance of these results to clinical and anthropological pursuits are discussed. Several recommendations for future investigations are made

Lot- und Profiländerung der Wirbelsäule durch das Tragen eines Schulranzens bei 11- bis 14-jährigen Kindern

Es liegen zum Teil widersprüchliche Aussagen der Studien zur Auswirkung einer Belastung durch einen Schulranzen auf die Wirbelsäule vor. Bei den wenigen vorhanden Studien fand eine Betrachtung der Fragestellung mit unterschiedlichen Methoden und verschiedenen Gewichtsbelastungen statt. Auf Grund der differenten Herangehensweisen der Studien, die zu dem Thema Auswirkungen des Schulranzens auf die Wirbelsäulenform durchgeführt wurden, ist es das Ziel dieser Studie die Veränderungen der Wirbelsäulenparameter durch das Gewicht eines Schulranzens mittels Rasterstereographie genauer zu untersuchen. Hierbei ist diese Studie eine der ersten Studien, die auf die für die Kinder wenig belastende Möglichkeit der Raststereographie zurückgreift. In der Raststereographie können die Parameter Kyphose- und Lordosewinkel, Lot- und Seitabweichung und Oberflächenrotation gemessen werden. Der Kyphose- und Lordosewinkel spiegeln eine Änderung der Wirbelsäule in der sagittalen Ebene wieder und zeigen, ob es bei einer Gewichtsbelastung zu einer Verstärkung, Abflachung oder einem Gleichbleiben der Rückenform komm

Estimating Symmetry/Asymmetry in the Human Torso: A Novel Computational Method

Asymmetry in human body has largely been based on bilateral traits and/or subjective estimates, with potential usage in fields such as medicine, rehabilitation and apparel product design. In case of apparel, asymmetry in human body has been measured primarily by estimating differential linear measurement of bilateral traits. However, the characteristics of asymmetry can be better understood and be useful for clinicians and designers if it is quantified by considering the whole 3D surface. To address the prevailing issues in measuring asymmetry objectively, this research attempts to develop a novel method to quantify asymmetry that is robust, effective and non-invasive in operation. The method discussed here uses 3D scans of human torso to estimate asymmetry as a numerical index. Furthermore, using skeletal landmarks, twist and tilt measurements of the torsos are computed numerically. Together, these three measures can characterize the asymmetric/symmetric nature of a human torso. The approach taken in this research uses cross sections of torso to estimate local plane of symmetry that equi-divides a given cross section on the basis of its area, and connecting those planes to form a global surface that divides the torso volumetrically. The computational approach in estimating the area of cross section is based on the Green's theorem. The developed method was validated by both testing it on a known geometric model and by comparing the estimated index with subjective ratings by experts. This method has potential applications in various fields requiring characterizing asymmetry i.e., in case of scoliosis patients as diagnostic tool or an evaluation metric for rehabilitation efficiency, for body builders, and fashion models as an evaluation tool.Design, Housing and Merchandisin