Journal of biomechanics
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Journal of biomechanics · Dec 2019
Complexity, symmetry and variability of forward and backward walking at different speeds and transfer effects on forward walking: Implications for neural control.
This study aimed to investigate effects of walking direction and speed on gait complexity, symmetry and variability as indicators of neural control mechanisms, and if a period of backward walking has acute effects on forward walking. Twenty-two young adults attended 2 visits. In each visit participants walked forwards at preferred walking speed (PWS) for 3-minutes (pre) followed by 5-minutes walking each at 80%, 100% and 120% of PWS of either forward or backward walking then a further 3-minutes walking forward at PWS (post). ⋯ No effects were found for harmonic ratio. These results suggest during backward walking trunk motion is rigidly controlled but central pattern generators responsible for temporal gait patterns are less refined for backward walking. However, in both directions complexity increased as speed increased suggesting additional constraint of trunk motion, normally characterised by reduced complexity, is not applied as speed increases.
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Journal of biomechanics · Nov 2019
Effects of foot orthoses on dynamic balance and basketball free-throw accuracy before and after physical fatigue.
While it is not uncommon for athletes to use foot orthoses to relieve pain and improve sports performance, little has been known about their effects on basketball performance. Free-throw basketball shooting is very important. However, fatigue deteriorates postural balance which might decrease free-throw shooting performance. ⋯ Results revealed that fatigue significantly increased coefficient of variance of medial-lateral center of pressure (CoP) excursion when participants worn flat control orthoses (p < 0.05). Meanwhile, foot orthoses improved dynamic balance during shooting as they significantly reduced total resultant and anterior-posterior sway excursions as well as resultant and anterior-posterior CoP velocities, and base of support area. Although this study found that fatigue and orthoses did not significantly affect the scores gained by free-throw shooting, the significant improvements in dynamic balance during shooting with the use of foot orthoses could have considerable impact on motor control during basketball shooting.
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Journal of biomechanics · Jul 2019
The sensitivity to inter-subject variability of the bridging vein entry angles for prediction of acute subdural hematoma.
Acute subdural hematoma (ASDH) is one of the most frequent traumatic brain injuries (TBIs) with high mortality rate. Bridging vein (BV) ruptures is a major cause of ASDH. The KTH finite element head model includes bridging veins to predict acute subdural hematoma due to BV rupture. ⋯ Moreover, the models with maximum and minimum entry angles give an insight of how BV biovariability can influence ASDH. In order to further improve the successful prediction rate, more biofidelic data are needed both with respect to bridging vein material properties and geometry. Furthermore, more experimental data are needed in order to investigate the behaviour of FE head models in depth.
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Journal of biomechanics · Jun 2019
A bipedal compliant walking model generates periodic gait cycles with realistic swing dynamics.
A simple spring mechanics model can capture the dynamics of the center of mass (CoM) during human walking, which is coordinated by multiple joints. This simple spring model, however, only describes the CoM during the stance phase, and the mechanics involved in the bipedality of the human gait are limited. In this study, a bipedal spring walking model was proposed to demonstrate the dynamics of bipedal walking, including swing dynamics followed by the step-to-step transition. ⋯ The proposed model generates periodic gaits with dynamics-driven step-to-step transitions and realistic swing dynamics. While preserving the mimicry of the CoM and ground reaction force (GRF) data at various gait speeds, the proposed model emulated the kinematics of the swing leg. This result implies that the dynamics of human walking generated by the actuations of multiple body segments is describable by a simple spring mechanics.