Developmental Biomechanics Research Articles

Correction to: 'Developmental biomechanics and age polyethism in leaf-cutter ants' (2023) by Püffel et al.

Correction to: 'Developmental biomechanics and age polyethism in leaf-cutter ants' (2023) by Püffel et al.

Developmental biomechanics and age polyethism in leaf-cutter ants.

Many social insects display age polyethism: young workers stay inside the nest, and only older workers forage. This behavioural transition is accompanied by genetic and physiological changes, but the mechanistic origin of it remains unclear. To investigate if the mechanical demands on the musculoskeletal system effectively prevent young workers from foraging, we studied the biomechanical development of the bite apparatus in Atta vollenweideri leaf-cutter ants. Fully matured foragers generated peak in vivo bite forces of around 100 mN, more than one order of magnitude in excess of those measured for freshly eclosed callows of the same size. This change in bite force was accompanied by a sixfold increase in the volume of the mandible closer muscle, and by a substantial increase of the flexural rigidity of the head capsule, driven by a significant increase in both average thickness and indentation modulus of the head capsule cuticle. Consequently, callows lack the muscle force capacity required for leaf-cutting, and their head capsule is so compliant that large muscle forces would be likely to cause damaging deformations. On the basis of these results, we speculate that continued biomechanical development post eclosion may be a key factor underlying age polyethism, wherever foraging is associated with substantial mechanical demands.

The Biomechanics of Spinal Deformity in Adolescent Idiopathic Scoliosis

Given the variety of anatomic and physical variations that exist, the biomechanics of Adolescent Idiopathic Scoliosis (AIS) comprise a complex topic. Representing the fundamental mechanism behind the three-dimensional deformities observed in this condition, AIS develops as a result of these complex interactions between pathoanatomy and the developmental biomechanics of the spine. The progressive nature of the deformity relates to the interplay between bony anatomical alterations and the surrounding soft tissue response. Various classification systems have evolved to better understand AIS and provide guidance for its management, and myriad techniques have been developed to address the correction of spinal deformity in these patients. For appropriately selected patients, the treating surgeon must exploit all biomechanical advantages available t counteract these deforming forces, and it is important that the biomechanics contributing to the progression of this condition be understood and corrected. All aspects of the case, including preoperative positioning and implant utilization, play a role in the amount of correction that can be obtained and maintained. These implants affect— and are affected by the forces present on the deformed spine, and manipulation of the surrounding anatomy may aid in obtaining the best surgical outcome.

Developmental biomechanics of the human cervical spine

Head and neck injuries, the leading cause of death for children in the U.S., are difficult to diagnose, treat, and prevent because of a critical void in our understanding of the biomechanical response of the immature cervical spine. The objective of this study was to investigate the functional and failure biomechanics of the cervical spine across multiple axes of loading throughout maturation. A correlational study design was used to examine the relationships governing spinal maturation and biomechanical flexibility curves and tolerance data using a cadaver human in vitro model. Eleven human cadaver cervical spines from across the developmental spectrum (2–28 years) were dissected into segments (C1-C2, C3-C5, and C6-C7) for biomechanical testing. Non-destructive flexibility tests were performed in tension, compression, flexion, extension, lateral bending, and axial rotation. After measuring their intact biomechanical responses, each segment group was failed in different modes to measure the tissue tolerance in tension (C1-C2), compression (C3-C5), and extension (C5-C6). Classical injury patterns were observed in all of the specimens tested. Both the functional (p<0.014) and failure (p<0.0001) mechanics exhibited significant relationships with age. Nonlinear flexibility curves described the functional response of the cervical spine throughout maturation and elucidated age, spinal level, and mode of loading specificity. These data support our understanding of the child cervical spine from a developmental perspective and facilitate the generation of injury prevention or management schema for the mitigation of child spine injuries and their deleterious effects.

INTEGRATING MECHANICAL CONTROL THEORY INTO MODELS OF BIOLOGICAL DEVELOPMENT — ANALYTICAL REVIEW

This paper presents both a general review on developmental biomechanics and a concrete proposition for the computation of a symmetry breaking instability of a model of biological development in terms of self-organization theory. The necessary biological and physical facts taken from the literature are described and discussed in the context of a unified statement of the problems for mathematical modeling of pattern formation. This is then applied to planar cell polarization (PCP) of the Drosophila wing. In this way, the process is modeled by an elastopolarization equation. In terms of this statement, the mechanical specificity (interaction with basal plate) of wing PCP is characterized. Some aspects of modeling somite formation as well as other developmental processes are also concerned.

Developmental biomechanics of the cervical spine: Tension and compression

Epidemiological data and clinical indicia reveal devastating consequences associated with pediatric neck injuries. Unfortunately, neither injury prevention nor clinical management strategies will be able to effectively reduce these injuries or their effects on children, without an understanding of the cervical spine developmental biomechanics. Thus, we investigated the relationship between spinal development and the functional (stiffness) and failure biomechanical characteristics of the cervical spine in a baboon model. A correlation study design was used to define the relationships between spinal tissue maturation and spinal biomechanics in both tension and compression. Eighteen baboon cervical spine specimens distributed across the developmental spectrum (1–26 human equivalent years) were dissected into osteoligamentous functional spinal units. Using a servo-hydraulic MTS, these specimens (Oc–C2, C3–C4, C5–C6, C7–T1) were non-destructively tested in tension and compression and then displaced to failure in tension while measuring the six-axes of loads and displacements. The functions describing the developmental biomechanical response of the cervical spine for stiffness and normalized stiffness exhibited a significant direct relationship in both tension and compression loading. Similarly, the tensile failure load and normalized failure load demonstrated significant maturational increases. Further, differences in biomechanical response were observed between the spinal levels examined and all levels exhibited clinically relevant failure patterns. These data support our understanding of the child cervical spine from a developmental biomechanics perspective and facilitate the development of injury prevention or management schema for the mitigation of child spine injuries and their deleterious effects.

The puzzles of motor development: how the study of developmental biomechanics contributes to the puzzle solutions

Four questions shape inquiry into the development of movement skills: (1) What is the source of new behaviours in the movement repertoire? (2) What is the definition of competence in the movement? (3) What are the mechanisms of change that support and trigger the emergence of new skills? (4) How adaptable is the neuromotor system? The variables of description and mechanisms and the experimental methods of biomechanics provide unique insight to each question. Understanding the interaction between biology and mechanics and this changing dynamic across the lifespan is important to understand human motor development. Copyright © 2005 John Wiley & Sons, Ltd.

The Effect of Physical Education Program on the Development of Motor Skill in Schoolchildren

For the purpose of studying the difference of development of jumping skill in schoolchildren in the different kind of exercise environment, the motion of standing long jump was analyzed by the method of Developmental Biomechanics (Kinesiology). Subjects were 6, 8, and 10-year-old children in the Republic of Honduras and in Japan. The experimental group in Honduras participated in the Japanese style program of physical education for 2 years, and the other control group in Honduras did not take any program of physical education.Results of performance test, evaluation of jumping pattern, and motion analysis indicate that the skill of standing long jump of Japanese children ranked at the highest level followed by that of the experimental group and the control one, and that the development of skill was reflected in the excellent performance in Japanese and the experimental school children. In the control group, no remarkable difference was recognized among the skills of 6, 8, and 10-year-old children, and the difference of performance test score among age groups was supposed to be brought from the growth of physique and/or physical resource.