Abstract：
:Risk for injury during a fall depends on the position and velocity of the body segments at the moment of impact. One technique for reducing impact velocity is to absorb energy in the lower extremity muscles during descent, as occurs during squatting or sitting. However, the protective value of this response may depend on the time during descent when the response is initiated. We tested this hypothesis by conducting backward falling experiments with young women (n = 23; aged 21-29 years), who fell onto a soft gymnasium mattress after being suddenly releasing from an inclined position. In trials where subjects were released from a 5 degrees lean, average impact velocities were reduced by 18% when squatting was utilized as opposed to inhibited. Furthermore, increases in the release angle caused an increase in average impact velocity of 8% between lean angles of 2 degrees and 5 degrees, and 7% between lean angles of 5 degrees and 12 degrees. This was due to declines in peak extensor torques and peak flexion rotations, and corresponding reductions in both joint work and potential energy at impact. These results suggest that squatting during descent reduces impact severity, but the effectiveness of the response depends on the stage during descent when it is initiated, diminishing in benefit as the fall progresses and the state of imbalance grows increasingly severe.
journal_name
J Biomechjournal_title
Journal of biomechanicsauthors
Robinovitch SN,Brumer R,Maurer Jdoi
10.1016/j.jbiomech.2003.12.015keywords:
subject
Has Abstractpub_date
2004-09-01 00:00:00pages
1329-37issue
9eissn
0021-9290issn
1873-2380pii
S0021929003004780journal_volume
37pub_type
临床试验,杂志文章abstract：:The purpose of this study was to propose and validate a new simple method for calculation of center of mass work during field running, in order to avoid the use of costly and inconvenient measurement devices. This method relies on spring-mass model and measurements of average horizontal velocity, and contact and fligh...
journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/j.jbiomech.2019.109369
更新日期：2019-12-03 00:00:00
abstract：:Mesenchymal stem cells (MSCs) are the common precursors of several functionally disparate cell lineages. A plethora of chemical and physical stimuli contribute to lineage decisions and guidance, including mechanical stretch concomitant with physical movement. Here, we examined how stretch regulates MSC differentiation...
journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/j.jbiomech.2015.08.013
更新日期：2015-10-15 00:00:00
abstract：:Flexure is a major deformation mode of the aortic valve (AV) leaflet, particularly in the commissural region where the upper portion of the leaflet joins the aortic root. However, there are no existing data known on the mechanical properties of leaflet in the commissural region. To address this issue, we quantified th...
journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/j.jbiomech.2005.10.026
更新日期：2006-01-01 00:00:00
abstract：OBJECTIVES:To assess the ability of a biomechanical impact model to predict the likelihood of distal radius fracture in children using data gathered for a previous epidemiological case-control study of falls from playground equipment. METHODOLOGY:Factor of Risk (FR) values were generated for each of selected subjects ...
journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/j.jbiomech.2004.11.028
更新日期：2006-01-01 00:00:00
abstract：:A novel technique to measure in vitro disc pressures in human cervical spine specimens was developed. A miniature pressure transducer was used and an insertion technique was designed to minimise artefacts due to insertion. The technique was used to measure the intradiscal pressure in cervical spines loaded in pure axi...
journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/s0021-9290(00)00205-0
更新日期：2001-04-01 00:00:00
abstract：:The aim of this study was to obtain insight into the coactivation behaviour of the jaw muscles under various a priori defined static loading conditions of the mandible. As the masticatory system is mechanically redundant, an infinite number of recruitment patterns is theoretically possible to produce a certain bite fo...
journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/0021-9290(90)90303-k
更新日期：1990-01-01 00:00:00
abstract：:Bone has the ability to adapt its structure in response to the mechanical environment as defined as Wolff's Law. The alignment of trabecular structure is intended to adapt to the particular mechanical milieu applied to it. Due to the absence of normal mechanical loading, it will be extremely important to assess the an...
journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/j.jbiomech.2012.04.022
更新日期：2012-06-26 00:00:00
abstract：:Within the context of improving knowledge of the structure-function relations for trabecular bone for cyclic loading, we hypothesized that the S-N curve for cyclic compressive loading of trabecular bone, after accounting for differences in monotonic strength behavior, does not depend on either site or species. Thirty-...
journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/s0021-9290(03)00245-8
更新日期：2004-02-01 00:00:00
abstract：:Subject-specific musculoskeletal models require accurate values of muscle moment arms. The aim of this study was to compare moment arms of wrist tendons obtained from non-invasive magnetic resonance imaging (MRI) to those obtained from an in vitro experimental approach. MRI was performed on ten upper limb cadaveric sp...
journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/j.jbiomech.2017.12.024
更新日期：2018-02-08 00:00:00
abstract：:Unnatural dynamics of the notorious vortex in the left ventricle is often associated with cardiac disease. Understanding how different cardiac diseases alter the flow physics in the left ventricle may therefore provide a powerful tool for disease detection. In this work, the fluid dynamics in the left ventricle subjec...
journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/j.jbiomech.2018.07.023
更新日期：2018-09-10 00:00:00
abstract：:When balance is disturbed, location of the center of pressure (COP) contributes to a person's ability to recover from a perturbation. This study investigated COP control prior to first step lift-off (FSLO) during lateral perturbations in older non-fallers and fallers. 38 non-fallers and 16 fallers received lateral wai...
journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/j.jbiomech.2015.02.012
更新日期：2015-04-13 00:00:00
abstract：:Propulsive forces generated by swimmers hand/forearm, have been studied through experimental tests. However, there are serious doubts as to whether forces quantified in this way are accurate enough to be meaningful. In order to solve some experimental problems, some numerical techniques have been proposed using Comput...
journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/j.jbiomech.2005.03.012
更新日期：2006-01-01 00:00:00
abstract：:The role of bone water in the activity of this organ is essential in structuring apatite crystals, providing pathways for nutrients and waste involved in the metabolism of bone cells and participating in bone remodelling mechanotransduction. It is commonly accepted that bone presents three levels of porosity, namely t...
journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/j.jbiomech.2015.07.025
更新日期：2015-09-18 00:00:00
abstract：:Chemically defined serum-free medium has been shown to better maintain the mechanical integrity of articular cartilage explants than serum-supplemented medium during long-term in vitro culture, but little is known about its effect on cellular mechanisms. We hypothesized that the chemically defined culture medium could...
journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/j.jbiomech.2015.02.005
更新日期：2015-04-13 00:00:00
abstract：:This paper presents a general method for simulating the movement of the lower extremity during human walking. It is based upon two separate algorithms: one for single support (an open kinematic chain), and the other for the double support phase (a closed-loop linkage). Central to each of these is the recursive Newton-...
journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/0021-9290(88)90250-3
更新日期：1988-01-01 00:00:00
abstract：:Sitting is often assumed to involve high loads on the spine as well as on implants for stabilising the spine. Loads on internal spinal fixation devices were therefore measured in ten patients sitting on several types of seats, including a stool, a stool with a padded wedge, a chair, a physiotherapy ball, a knee-stool,...
journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/s0021-9290(01)00073-2
更新日期：2001-08-01 00:00:00
abstract：:Muscle activity has previously been suggested to minimize soft-tissue resonance which occurs at heel-strike during walking and running. If this concept were true then the greatest vibration damping would occur when the input force was closest to the resonant frequency of the soft-tissues at heel-strike. However, this ...
journal_title：Journal of biomechanics
pub_type： 临床试验,杂志文章,随机对照试验
doi：10.1016/s0021-9290(03)00216-1
更新日期：2003-12-01 00:00:00
abstract：:The effect of sub-cellular mechanical loads on the behavior of fibroblasts was investigated using magnetoelastic (ME) materials, a type of material that produces mechanical vibrations when exposed to an external magnetic AC field. The integration of this functionality into implant surfaces could mitigate excessive fib...
journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/j.jbiomech.2018.02.007
更新日期：2018-04-11 00:00:00
abstract：:The longitudinal growth of long bones occurs in growth plates where chondrocytes synthesize cartilage that is subsequently ossified. Altered growth and subsequent deformity resulting from abnormal mechanical loading is often referred to as mechanical modulation of bone growth. This phenomenon has key implications in t...
journal_title：Journal of biomechanics
pub_type： 杂志文章,评审
doi：10.1016/j.jbiomech.2009.05.021
更新日期：2009-08-25 00:00:00
abstract：:Computation of muscle excitation patterns that produce coordinated movements of muscle-actuated dynamic models is an important and challenging problem. Using dynamic optimization to compute excitation patterns comes at a large computational cost, which has limited the use of muscle-actuated simulations. This paper int...
journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/s0021-9290(02)00432-3
更新日期：2003-03-01 00:00:00
abstract：:The tibia from six-week old chickens that develop idiopathic scoliosis were studied with stress relaxation experiments and torsional strength testing. Most parameters observed did not show any significant differences between tibias obtained from chickens with scoliosis and tibias from the control birds; however, the r...
journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/0021-9290(83)90046-5
更新日期：1983-01-01 00:00:00
abstract：:Several studies have attributed the prevalence of low back pain (LBP) in helicopter pilots mainly to poor posture in-flight and whole-body vibration, with the latter hypothesis particularly related to a cyclic response of the erector spine (ES) muscle to vibration. This work aims to determine if helicopter vibration a...
journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/s0021-9290(01)00090-2
更新日期：2001-10-01 00:00:00
abstract：:Adverse wall shear stress (WSS) patterns are known to play a key role in the localisation, formation, and progression of intracranial aneurysms (IAs). Complex region-specific and time-varying aneurysmal WSS patterns depend both on vascular morphology as well as on variable systemic flow conditions. Computational fluid...
journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/j.jbiomech.2016.10.005
更新日期：2016-12-08 00:00:00
abstract：:Patello-femoral disorders are often caused by changes of patello-femoral and/or tibio-femoral kinematics. However, until now there has been no quantitative in vivo technique, that is able to obtain 3D kinematics and contact areas of all knee compartments simultaneously on a non-invasive basis. The aim of this study wa...
journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/j.jbiomech.2003.09.034
更新日期：2004-06-01 00:00:00
abstract：:Measures of local dynamic stability, such as the local divergence exponent (lambda*(s)) quantify how quickly small perturbations deviate from an attractor that defines the motion. When the governing equations of motion are unknown, an attractor can be reconstructed by defining an appropriate state space. However, stat...
journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/j.jbiomech.2009.03.015
更新日期：2009-06-19 00:00:00
abstract：:The distal foot power equation is a simple yet powerful tool for estimating the power dissipation or generation within the foot even while modeling it as a rigid body. It was introduced over two decades ago, but has seen a resurgence of use in recent years. Nevertheless, the theoretical justification for this formula ...
journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/j.jbiomech.2020.109964
更新日期：2020-08-26 00:00:00
abstract：:It is generally accepted that spine control and stability are relevant for the prevention and rehabilitation of low back pain (LBP). However, there are conflicting results in the literature in regards to how these variables are modified in the presence of LBP. The aims of the present work were twofold: (1) to use noxi...
journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/j.jbiomech.2017.04.010
更新日期：2017-06-14 00:00:00
abstract：:When the foot impacts the ground in running, large forces and loading rates can arise that may contribute to the development of overuse injuries. Investigating which biomechanical factors contribute to these impact loads and loading rates in running could assist clinicians in developing strategies to reduce these load...
journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/j.jbiomech.2013.10.026
更新日期：2014-01-03 00:00:00
abstract：:Motion capture systems are widely used to measure human kinematics. Nevertheless, users must consider system errors when evaluating their results. Most validation techniques for these systems are based on relative distance and displacement measurements. In contrast, our study aimed to analyse the absolute volume accur...
journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/j.jbiomech.2018.04.009
更新日期：2018-06-06 00:00:00
abstract：:A sticky chain model has been proposed to describe the unfolding of spectrin network under applied mechanical loads. With the model, the response of a red blood cell (RBC) under static and cyclic shear loading has been predicted, which agrees qualitatively with relevant experimental results. ...
journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/j.jbiomech.2008.05.028
更新日期：2008-08-07 00:00:00
