Search results for "trunk"
showing 10 items of 196 documents
Central Neural Blocks
1988
The spinal column consists of vertebral bodies which together form 7 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 4 coccygeal vertebrae (see Transparency 1). A typical vertebra consists of two basic parts: the ventral vertebral body and the dorsal vertebral arch. Between the vertebral bodies are the intervertebral disks, which give the spinal column its flexibility. Together, the vertebral bodies and the intervertebral disks form a strong column supporting the head and trunk, while the vertebral arch protects the spinal cord. When the spinal column is viewed from the side, four flexures are visible: the thoracic and the sacrococcygeal flexures are concave ventrally, while the cervical and…
Reduction and variability of trunk spines in the acanthocephalan Corynosoma cetaceum: the role of physical constraints on attachment
2005
. In this study, we investigated a functional trade-off between trunk attachment and trunk-spine development in the acanthocephalan Corynosoma cetaceum. The worms live attached to the stomach and upper intestine of their cetacean definitive hosts, using the proboscis and spiny foretrunk as the main holdfast; the spiny hindtrunk can also attach by bending ventrally. When the hindtrunk bends, ventral compression generates an anterior fold (AF) and a posterior fold (PF). A morphological analysis based on 7,823 individuals collected from 10 franciscana dolphins, Pontoporia blainvillei, revealed that spines were smaller and more variable in size and occurrence in the folds than on neighboring ar…
Patterns of trunk spine growth in two congeneric species of acanthocephalan: investment in attachment may differ between sexes and species.
2012
SUMMARYAcanthocephalans have evolved a hooked proboscis and some taxa have trunk spines to attach to their definitive hosts. These structures are generated before being used, thus a key question is how investment in attachment could optimally be allocated through the ontogeny. The number and arrangement of hooks and spines are never modified in the definitive host, but it is unclear whether these structures grow during adult development. A comparison of the size of trunk spines between cystacanths and adults of Corynosoma cetaceum and C. australe indicated that spines grow in both species, but only in females, which also had significantly larger spines than males. This sexual dimorphism did…
AB1197 Changes in Lumbar Spinopelvic Pattern of Movement Influence the Flexion Relaxation of the Erector Spinae
2015
Background In healthy subjects, the erector spinae muscles (ES) exhibits a relaxation of its electrical activity when the trunk is nearby its full flexion. Objectives To find out the influence of exhibiting a lumbar spine or a pelvis dominant pattern of movement during trunk flexion from upright position on the appearance of the myoelectric relaxation of the erector spinae. In healthy subjects, the erector spinae muscles (ES) exhibits a relaxation of its electrical activity when the trunk is nearby its full flexion. Objectives To find out the influence of exhibiting a lumbar spine or a pelvis dominant pattern of movement during trunk flexion from upright position on the appearance of the my…
Different sitting positions influence cross country sit skiers performance : Sitting position influence on force generation and cycle characteristics
2018
Cross country sit skiing is a Paralympic discipline in which athletes due to physical impairment ski sitting on a sit-ski. The impairment influences performance directly and also through sitting position. Athletes with a better trunk control usually adopt a sitting position called “kneeing” in which the hip joints are higher than the knee joints. In contrast, athletes with high impact of impairment prefer a sitting position called “knee high” in which the hip joints are lower than the knee joints. Able bodied athletes skiing on the ergometer in these two sitting positions showed different performance. However, to the best of authors’ knowledge, no studies have examined performance, force pr…
2020
This study focused on resolving the differences in economy between two common sit-skiing postures used by disabled athletes, suspected to be the most and least effective. Ten experienced non-disabled male cross-country skiers went through an incremental testing protocol with an ergometer simulating double poling in two sitting postures "kneeing" and "knee-high." The protocol consisted of 3 × 4 min steady-state stages (13, 22, and 34% of maximal sprint power output). Subjects' respiratory gases and heart rate were measured and blood lactate concentrations were determined. In addition, pulling forces and motion capture recordings were collected. Oxygen consumption was 15.5% (p < 0.01) higher …
AB1057 risk factors associated with different lumbopelvic patterns of movement
2016
Background Rapid flexion movement increases the loading on the spine and it increases the risk of injuries 1 . In asymptomatic subjects lumbar-dominant and pelvis-dominant patterns of movement during trunk flexion have been observed 2,3 . However, little information about lumbar spine kinematics has been provided. Objectives To find out whether exhibiting different lumbopelvic patterns of movement during trunk flexion affects the kinematics of the lumbar spine in terms of velocity of motion. Methods Differential lumbar spine and pelvis angular displacement during the time course of a standardised sagittal trunk flexion from an upright position was recorded with an electromagnetic tracking d…
Effect of Sitting Posture on Sit-Skiing Economy in Non-disabled Athletes
2020
This study focused on resolving the differences in economy between two common sit-skiing postures used by disabled athletes, suspected to be the most and least effective. Ten experienced non-disabled male cross-country skiers went through an incremental testing protocol with an ergometer simulating double poling in two sitting postures “kneeing” and “knee-high.” The protocol consisted of 3 × 4 min steady-state stages (13, 22, and 34% of maximal sprint power output). Subjects' respiratory gases and heart rate were measured and blood lactate concentrations were determined. In addition, pulling forces and motion capture recordings were collected. Oxygen consumption was 15.5% (p < 0.01) higher …
Effect of saddle height on skin temperature measured in different days of cycling
2016
Infrared thermography can be useful to explore the effects of exercise on neuromuscular function. During cycling, it could be used to investigate the effects of saddle height on thermoregulation. The aim of this study was to examine whether different cycling postures, elicited by different knee flexion angles, could influence skin temperature. Furthermore, we also determined whether the reproducibility of thermal measurements in response to cycling differed in the body regions affected or not affected by saddle height. Sixteen cyclists participated in three tests of 45 min of cycling at their individual 50 % peak power output. Each test was performed in a different knee flexion position on …
Physiological and Structural Responses to Prolonged Water Deficit in Young Trees of Two Olive Cultivars
2022
This study aimed to characterize the physiological and structural responses of potted one-year-old olive trees belonging to two olive cultivars—‘Nocellara del Belice’ and ‘Cerasuola’—exposed to prolonged drought under greenhouse conditions. Two irrigation treatments based on evapotranspiration (ET) were imposed for 69 days, i.e., well-watered (WW, 100% ET) and drought-stressed (DS, 10–30% ET). Leaf stomatal conductance (gs), stem water potential (Ψstem), transpiration (E), photosynthetic capacity (Amax), water use efficiency (WUE), stem (Kstem) and root (Kroot) hydraulic conductance, trunk diameter variations (TDV), and leaf patch attenuated pre…