Mechanisms of control in hope jumping as a function of task constraint

Hope jumping is a motor task that can be performed in different ways and with ropes with different physical characteristics (weight, texture, and size). When the rope jump is performed with the rope being self controlled, relevant haptic information is available for the action control. In order to examine the adjustments made by the performer in rope jumping with ropes of different weight, eight male university students performed a sequence of 30 rope-jumping with ropes of 180, 255, and 330g. The rope was turn by the participant in a selfpaced mode. Such sequences were registered in video and the following variables were obtained: continuous relative phase, rope beat frequency, jump height, rope height, and temporal interval between the moment of the loss of the feet contact with the floor and the crossing of the rope under the feet. The results showed that only the rope frequency changed as a function of the rope weight, suggesting that the upper limbs when turning the rope are responsible for the adjustments in order to maintain the same level of performance.

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Biomechanical effects of the addition of a precision constraint on a collective load carriage task

10.1101/2021.07.09.451742 ◽

2021 ◽

Author(s):

Nour Sghaier ◽

Guillaume Fumery ◽

Vincent Fourcassie ◽

Nicolas Alain Turpin ◽

Pierre Moretto

Keyword(s):

Recovery Rate ◽

Center Of Mass ◽

Motor Task ◽

Target Position ◽

Load Carriage ◽

Upper Limbs ◽

Cognitive Components ◽

Study Results ◽

Accuracy Constraint ◽

The Moment

Team lifting is a complex and collective motor task that possesses both motor and cognitive components. The purpose of this study was to investigate to what extent the biomechanics of a collective load carriage is affected when a dyad of individuals is performing a carrying task with an additional accuracy constraint. Ten dyads performed a first condition in which they collectively transported a load (CC), and a second one in which they transported the same load while maintaining a ball in a target position on its top (PC). The recovery rate, amplitude, and period of the center-of-mass (COM) trajectory were computed for the whole system (dyad + table = PACS). We analyzed the forces and moments exerted at each joint of the upper limbs of the subjects. We observed a decrease in the overall performance of the dyads when the Precision task was added, i.e., i) the velocity and amplitude of CoMPACS decreased by 1,7% and 5,8%, respectively, ii) inter-subject variability of the Moment-Cost-Function decreased by 95% and recovery rate decreased by 19,2% during PC. A kinetic synergy analysis showed that the subjects reorganized their coordination in the PC. Our results demonstrate that adding a precision task affects the economy of collective load carriage. Notwithstanding, the joint moments at the upper-limbs are better balanced and co-vary more across the paired subjects during the precision task. Our study results may find applications in domains such as Ergonomics, Robotics-developments, and Rehabilitation.

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Determination of Neuromuscular Control of the Upper Limbs in Children - Case Study

BRAIN. BROAD RESEARCH IN ARTIFICIAL INTELLIGENCE AND NEUROSCIENCE ◽

10.18662/brain/11.4sup1/155 ◽

2020 ◽

Vol 11 (4Sup1) ◽

pp. 46-61

Author(s):

Carmen-Magdalena Camenidis ◽

◽

Irina Băițel ◽

Amalia Oatu ◽

Octavian Amzulescu ◽

...

Keyword(s):

Kinematic Chain ◽

Neuromuscular Control ◽

Female Gender ◽

Upper Limbs ◽

Motor Action ◽

Muscle Groups ◽

The Moment ◽

The Right

The objective of this case study is to observe the existence of an anticipation mechanism at the muscle groups level of the upper limbs. We tried to highlighted this anticipation process by measuring the potential of surface electric for some muscle groups representing the kinematic chain on the right side, involved in the motor action of catching a basketball and a 3kg medicine ball with two hands to the chest. We conducted a case study of a 13-year-old child, female gender. As a measurement method, we used surface electromyography signals of the EMG Trigno Delsys wireless system with 16 electrodes. We determined the moment when the muscles come into action by increasing the potential of surface electric and the moment when the action of catching the ball takes place, using the information provided by the accelerometers incorporated in the sensors of the Delsys equipment used. Therefore, we obtained information about how different muscle groups come into action which helped us to get an idea of how the child's movement is structured. Based on results of accelerations and EMG signals acquired we have formulated conclusions regarding the neuromuscular control of the tested subject. We also planned for the future to test a larger group of participants in the study research of anticipation mechanism in children who do not practice any performance sports.

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Soliton–Breather Interaction: The Modified Korteweg–de Vries Equation Framework

Symmetry ◽

10.3390/sym12091445 ◽

2020 ◽

Vol 12 (9) ◽

pp. 1445

Author(s):

Ekaterina Didenkulova ◽

Efim Pelinovsky

Keyword(s):

Optical Fibers ◽

Water Waves ◽

Relative Phase ◽

Vries Equation ◽

Decisive Role ◽

Pairwise Interactions ◽

De Vries ◽

Series Of Experiments ◽

Stratified Ocean ◽

The Moment

Pairwise interactions of particle-like waves (such as solitons and breathers) are important elementary processes that play a key role in the formation of the rarefied soliton gas statistics. Such waves appear in different physical systems such as deep water, shallow water waves, internal waves in the stratified ocean, and optical fibers. We study the features of different regimes of collisions between a soliton and a breather in the framework of the focusing modified Korteweg–de Vries equation, where cubic nonlinearity is essential. The relative phase of these structures is an important parameter determining the dynamics of soliton–breather collisions. Two series of experiments with different values of the breather’s and soliton’s relative phases were conducted. The waves’ amplitudes resulting from the interaction of coherent structures depending on their relative phase at the moment of collision were analyzed. Wave field moments, which play a decisive role in the statistics of soliton gases, were determined.

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Stroke-affected upper extremity movement assessment via continuous relative phase analysis

Measurement ◽

10.1016/j.measurement.2017.06.011 ◽

2017 ◽

Vol 110 ◽

pp. 84-89 ◽

Cited By ~ 2

Author(s):

Kristina Daunoravičienė ◽

Jurgita Žižienė ◽

Jolanta Pauk ◽

Adam Idzkowski ◽

Inga Raudonytė ◽

...

Keyword(s):

Upper Extremity ◽

Phase Analysis ◽

Relative Phase ◽

Movement Assessment ◽

Continuous Relative Phase ◽

Upper Extremity Movement

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Variability in kinematic coupling assessed by vector coding and continuous relative phase

Journal of Biomechanics ◽

10.1016/j.jbiomech.2010.05.014 ◽

2010 ◽

Vol 43 (13) ◽

pp. 2554-2560 ◽

Cited By ~ 54

Author(s):

Ross H. Miller ◽

Ryan Chang ◽

Jennifer L. Baird ◽

Richard E.A. Van Emmerik ◽

Joseph Hamill

Keyword(s):

Relative Phase ◽

Vector Coding ◽

Kinematic Coupling ◽

Continuous Relative Phase

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Comparison of Lumbopelvic Coordination between Trunk Flexion and Extension

Proceedings of the Human Factors and Ergonomics Society Annual Meeting ◽

10.1177/1541931213601215 ◽

2016 ◽

Vol 60 (1) ◽

pp. 937-941

Author(s):

Jie Zhou ◽

Xiaopeng Ning

Keyword(s):

Relative Phase ◽

Sagittal Plane ◽

Influential Factor ◽

Coordination Pattern ◽

Trunk Flexion ◽

Flexion Extension ◽

Continuous Relative Phase ◽

Phase Variability ◽

Coordination Patterns ◽

Flexion And Extension

Lumbopelvic coordination describes the relative contributions of lumbar and pelvis to the total trunk flexion/extension motion, which has been identified as a major influential factor to spinal loading. The current study investigated the differences in lumbopelvic coordination between trunk flexion and extension. Thirteen subjects performed pace-controlled trunk flexion/extension motions in the sagittal plane while lumbopelvic continuous relative phase and phase variability were quantified. The results demonstrated that compared with trunk extension, lumbopelvic continuous relative phase and phase variability were 28% and 117% greater in trunk flexion motion, respectively, which indicated a more anti-phase and unstable coordination pattern. Quantifying these coordination patterns helps identifying abnormal patterns and serves as normative benchmarks during low back pain rehabilitation.

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PORTRAIT AND HILBERT TRANSFORM METHODS FOR EVALUATING CONTINUOUS RELATIVE PHASE BETWEEN LOWER-LIMB JOINTS IN THE ELDERLY DURING WALKING

Journal of Mechanics in Medicine and Biology ◽

10.1142/s0219519421400388 ◽

2021 ◽

pp. 2140038

Author(s):

HYUK-JAE CHOI ◽

GYOOSUK KIM ◽

CHANG-YONG KO

Keyword(s):

Angular Velocity ◽

Hilbert Transform ◽

Lower Limb ◽

Cross Correlation ◽

Relative Phase ◽

The Elderly ◽

Transform Method ◽

Transform Methods ◽

Continuous Relative Phase ◽

The Hilbert Transform

In order to calculate the continuous relative phase (CRP) between joints, the portrait method based on the joint angle and angular velocity and the Hilbert transform method based on the analytical signal have been widely used. However, there are few comparisons of these methods. Therefore, the aim of this study is to quantitatively compare these methods by calculating the CRP in the lower-limb joints of the elderly during level free walking. Eighteen elderly female adults ([Formula: see text] year-old, [Formula: see text][Formula: see text]cm, [Formula: see text][Formula: see text]kg) wearing a Helen Hayes full-body marker set walked 10[Formula: see text]m on level ground at a self-selected velocity. The angles of the hip, knee, and ankle were measured. To calculate the CRP using the portrait method, the angular velocities were measured. Then, the phases between the angle and the angular velocity were calculated. To calculate the CRP using the Hilbert transform method, analytical signals were acquired. Then, the phases between the real and imaginary parts were calculated. A CRP was calculated as the difference between the phase in the proximal joint and the phase in the distal joint. To evaluate the similarity in the shape between the portrait and Hilbert transform methods, the cross-correlation was calculated. Bland–Altman plot analyses were performed to assess the agreement between these methods. For the root mean squares (RMSs) and standard deviations (SDs), a paired [Formula: see text]-test and the Pearson correlation between methods were evaluated. There were similarities in the in-phase or out-of-phase features and in the RMS and SD between the methods. Additionally, a higher cross-correlation and agreement between them were found. These results indicated the similarity between the portrait and Hilbert transform methods for the calculation of the CRP. Therefore, either method can be used to evaluate joint coordination.

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