Abstract：
:Gravity is a contributing force that is believed to influence strongly the control of limb movements since it affects sensory input and also contributes to task mechanics. By altering the relative contribution of gravitational force to the overall forces used to control pedaling at different body orientations, we tested the hypothesis that joint torque and muscle activation patterns would be modified to generate steady-state pedaling at altered body orientations. Eleven healthy subjects pedaled a modified ergometer at different body orientations (from horizontal to vertical), maintaining the same workload (80 J), cadence (60 rpm), and hip and knee kinematics. Pedal reaction forces and crank and pedal kinematics were measured and used to calculate joint torques and angles. EMG was recorded from four muscles (tibialis anterior, triceps surae, rectus femoris, biceps femoris). Measures of muscle activation (joint torque and EMG activity) showed strong dependence on body orientation, indicating that muscle activity is not fixed and is modified in response to altered body orientation. Simulations confirmed that, while joint torque changes were not necessary to pedal at different body orientations, observed changes were necessary to maintain consistent crank angular velocity profiles. Dependence of muscle activity on body orientation may be due to neural integration of sensory information with an internal model that includes characteristics of the endpoint, to produce consistent pedaling trajectories. Thus, both sensory consequences and mechanical aspects of gravitational forces are important determinants of locomotor tasks such as pedaling.
journal_name
J Biomechjournal_title
Journal of biomechanicsauthors
Brown DA,Kautz SA,Dairaghi CAdoi
10.1016/0021-9290(96)00038-3subject
Has Abstractpub_date
1996-10-01 00:00:00pages
1349-56issue
10eissn
0021-9290issn
1873-2380pii
0021929096000383journal_volume
29pub_type
杂志文章abstract：:In order to move the finger the tendon force must overcome the gliding resistance of the tendon as well as the forces to move the joints, finger inertias, and external load. These sources, combined, make up the work of flexion (WOF) which has been experimentally used to evaluate the finger function. In this study, we ...
journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/s0021-9290(02)00300-7
更新日期：2003-02-01 00:00:00
abstract：:The kinetics of the body's center of gravity during level walking were analyzed in 50 normal subjects and 47 patients. The three-dimensional displacements of the center of gravity were computed by the integration of force plate data. The energy levels and the power requirements of the center of gravity were also calcu...
journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/0021-9290(87)90328-9
更新日期：1987-01-01 00:00:00
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journal_title：Journal of biomechanics
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journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/j.jbiomech.2014.09.004
更新日期：2014-11-28 00:00:00
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journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/j.jbiomech.2018.11.016
更新日期：2019-01-23 00:00:00
abstract：:Lumbar interbody fusion is currently the gold standard in treating patients with disc degeneration or segmental instability. Despite it having been used for several decades, the non-union rate remains high. A failed fusion is frequently attributed to an inadequate mechanical environment after instrumentation. Finite e...
journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/j.jbiomech.2018.03.009
更新日期：2018-04-27 00:00:00
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journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/0021-9290(95)00083-6
更新日期：1996-04-01 00:00:00
abstract：:Vortex-ring production was studied in axisymmetric elastomeric ventricles designed to stimulate flow in a cardiovascular assist device. A flow visualization technique was used to investigate the effects of reducing the inlet diameter and predilating the ventricle on vortex travel in two ventricles of different shape a...
journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/0021-9290(95)00065-8
更新日期：1996-04-01 00:00:00
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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
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journal_title：Journal of biomechanics
pub_type： 杂志文章
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更新日期：2012-07-26 00:00:00
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journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/0021-9290(82)90022-7
更新日期：1982-01-01 00:00:00
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journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：
更新日期：1996-12-01 00:00:00
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journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/j.jbiomech.2018.12.009
更新日期：2019-02-14 00:00:00
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journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/j.jbiomech.2014.01.036
更新日期：2014-05-07 00:00:00
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journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：
更新日期：1996-12-01 00:00:00
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journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/j.jbiomech.2005.12.011
更新日期：2007-01-01 00:00:00
abstract：:Simple models are widely used to understand the mechanics of human walking. The optimization-based minimal biped model and spring-loaded-inverted-pendulum (SLIP) model are two popular models that can achieve human-like walking patterns. However, ground reaction forces (GRF) from these two models still deviate from exp...
journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/j.jbiomech.2019.04.028
更新日期：2019-06-11 00:00:00
abstract：:About one-third of older multiparous women are prone to stress urinary incontinence (SUI): unwanted urine loss during activities which suddenly raise intra-abdominal pressure. In this paper we describe and test a method for visualizing and analyzing the function of the urinary continence control system (CCS) under str...
journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/s0021-9290(97)81291-2
更新日期：1997-01-01 00:00:00
abstract：:Cerebral vasculature is several orders of magnitude stiffer than the brain tissue. However, only a handful of studies have investigated its potential stiffening effect on dynamic brain strains; yet, they report contradictory findings. Here, we reanalyze the cerebrovascular stiffening effect by incorporating vasculatur...
journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/j.jbiomech.2020.109732
更新日期：2020-05-07 00:00:00
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journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/j.jbiomech.2018.11.003
更新日期：2019-01-03 00:00:00
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pub_type： 杂志文章
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journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/j.jbiomech.2009.04.032
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journal_title：Journal of biomechanics
pub_type： 杂志文章
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更新日期：2011-02-03 00:00:00
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journal_title：Journal of biomechanics
pub_type： 杂志文章
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更新日期：2016-08-16 00:00:00
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journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/s0021-9290(00)00114-7
更新日期：2000-11-01 00:00:00
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journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/s0021-9290(02)00327-5
更新日期：2003-02-01 00:00:00
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journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/j.jbiomech.2014.10.011
更新日期：2014-11-28 00:00:00
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journal_title：Journal of biomechanics
pub_type： 杂志文章
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更新日期：2015-09-18 00:00:00
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journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/j.jbiomech.2006.11.003
更新日期：2007-01-01 00:00:00
abstract：:Biomechanical models may aid in improving diagnosis and treatment of wrist joint disorders. As input, geometrical information is required for model development. Previous studies acquired some elements of the average wrist joint geometry. However, there is a close geometric functional match between articulating surface...
journal_title：Journal of biomechanics
pub_type： 杂志文章
doi：10.1016/j.jbiomech.2009.11.003
更新日期：2010-03-22 00:00:00
