Influence of Back Support on the Sagittal Plane Biodynamic Response of Seated Human under Vertical Vibration

2014 ◽  
Vol 590 ◽  
pp. 74-85
Author(s):  
Fan Yang ◽  
Subhash Rakheja
Keyword(s):  
White Noise ◽  
Sagittal Plane ◽  
Vertical Vibration ◽  
The Body ◽  
Dynamic Responses ◽  
Upper Body ◽  
Apparent Mass ◽  
Frequency Range ◽  
Dynamic Interactions ◽  
Vibration Magnitude

The dynamic responses of the seated body exposed to vertical vibration are investigated at the two driving-points, formed by the upper body-backrest and buttock-pan interfaces in terms of force-motion relationships. The dynamic interactions of the seated body are characterized in the laboratory in terms of apparent masses at the two driving-points under white noise and track-measured random vertical vibration in the 0.5-40 Hz frequency range. The experiments were performed with 24 adult subjects seated on an idealized rigid seat, representing an automotive seat geometry. The vertical and fore-aft forces at the body-pan and body-backrest interfaces were measured to determine the apparent mass responses at the two driving-points. The results clearly revealed significant dynamic interactions of the upper body with the back support. The results also showed considerable influences of the vibration magnitude, body mass and the subjects’ hands position on the measured biodynamic responses.

Non-Linear Characteristics in the Dynamic Responses of Seated Subjects Exposed to Vertical Whole-Body Vibration

2002 ◽  
Vol 124 (5) ◽  
pp. 527-532 ◽  
Author(s):  
Yasunao Matsumoto ◽  
Michael J. Griffin
Keyword(s):  
Frequency Response ◽  
The Body ◽  
Dynamic Responses ◽  
Whole Body ◽  
Apparent Mass ◽  
Response Functions ◽  
Frequency Response Functions ◽  
Resonance Frequencies ◽  
Non Linear ◽  
Vibration Magnitude

The effect of the magnitude of vertical vibration on the dynamic response of the seated human body has been investigated. Eight male subjects were exposed to random vibration in the 0.5 to 20 Hz frequency range at five magnitudes: 0.125, 0.25, 0.5, 1.0 and 2.0 ms−2 r.m.s. The dynamic responses of the body were measured at eight locations: at the first, fifth, and tenth thoracic vertebrae (T1, T5, T10), at the first, third, and fifth lumbar vertebrae (L1, L3, L5) and at the pelvis (the posterior-superior iliac spine). At each location, the motions on the body surface were measured in the three orthogonal axes within the sagittal plane (i.e., the vertical, fore-and-aft, and pitch axes). The force at the seat surface was also measured. Frequency response functions (i.e., transmissibilities and apparent mass) were used to represent the responses of the body. Non-linear characteristics were observed in the apparent mass and in the transmissibilities to most measurement locations. Resonance frequencies in the frequency response functions decreased with increases in the vibration magnitude (e.g. for the vertical transmissibility to L3, a reduction from 6.25 to 4.75 Hz when the vibration magnitude increased from 0.125 to 2.0 ms−2 r.m.s.). The transmission of vibration within the spine also showed some evidence of a non-linear characteristic. It can be concluded from this study that the dynamic responses of seated subjects are clearly non-linear with respect to vibration magnitude, whereas previous studies have reported inconsistent conclusions. More understanding of the dependence on vibration magnitude of both the dynamic responses of the soft tissues of the body and the muscle activity (voluntary and involuntary) is required to identify the causes of the non-linear characteristics observed in this study.

Apparent Mass Responses of Seated Occupants Under Single and Dual (XZ) Axis Vibration

2010 ◽  
Author(s):  
S. Mandapuram ◽  
S. Rakheja ◽  
P.-E. Boileau ◽  
S. Maeda
Keyword(s):  
Sagittal Plane ◽  
Vertical Axis ◽  
The Body ◽  
Apparent Mass ◽  
Total Response ◽  
Coupling Effects ◽  
Minimal Coupling ◽  
Dynamic Interactions ◽  
Cross Axis ◽  
Male Subjects

This study investigated the biodynamic responses of the seated body to two-axis vibration applied along the fore-aft and vertical directions in the 0.5 to 20 Hz range, independently and simultaneously, using 9 adult male subjects. The measurements were performed with the subjects seated with and without the hands and back supports under two different magnitudes of vibration. The apparent mass responses distributed over the seat pan and the back support are determined in order to better understand the dynamic interactions of the body with the back support under single as well as dual-axis vibration. The results suggest strong influences of the back and hand supports, and considerable cross-axis apparent mass along the vertical axis. Only minimal coupling effects of dual axis vibration, however, could be observed, although coupled sagittal plane motions were perceived by the subjects. Using the linear system theory, the total response along each axis was also computed from the direct and cross-axis responses to individual axes vibration, which emphasized contributions due to cross-axis response and thus the coupling effects of multi-axis vibration.

Apparent mass of the seated human body during vertical vibration in the frequency range 2–100 Hz

Ergonomics ◽  
2020 ◽  
Vol 63 (9) ◽  
pp. 1150-1163
Author(s):  
Yu Huang ◽  
Penglin Zhang ◽  
Shihao Liang
Keyword(s):  
Human Body ◽  
Vertical Vibration ◽  
Apparent Mass ◽  
Frequency Range

scholarly journals Standard reference values of the upper body posture in healthy young female adults in Germany: an observational study

BMJ Open ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. e022236 ◽  
Author(s):  
Daniela Ohlendorf ◽  
Vanessa Fisch ◽  
Charlotte Doerry ◽  
Sebastian Schamberger ◽  
Gerhard Oremek ◽  
...  
Keyword(s):  
Observational Study ◽  
Sagittal Plane ◽  
Three Dimensional ◽  
Spinal Column ◽  
Young Female ◽  
The Body ◽  
Body Posture ◽  
Upper Body ◽  
Upper Body Posture ◽  
Standard Values

ObjectiveClassifications of posture deviations are only possible compared with standard values. However, standard values have been published for healthy male adults but not for female adults.DesignObservational study.SettingInstitute of Occupational Medicine, Social Medicine and Environmental Medicine, Goethe-University Frankfurt/Main.Participants106healthy female volunteers (21–30 years old; 25.1±2.7 years) were included. Their body weight ranged from 46 to 106 kg (60.3±7.9 kg), the heights from 1.53 to 1.82 m (1.69±0.06 m) and the body mass index from 16.9 kg/m² to 37.6 kg/m² (21.1±2.6 kg/m²).Outcome measuresA three-dimensional back scan was performed to measure the upper back posture in habitual standing. The tolerance ranges and CI were calculated. Group differences were tested by the Wilcoxon Mann-Whitney U test.ResultsIn normal posture, the spinal column was marginally twisted to the left, and the vertebrae were marginally rotated to the right. The kyphosis angle is larger than the lumbar angle. Consequently, a more kyphotic posture is observed in the sagittal plane. The habitual posture is slightly scoliotic with a rotational component (scapular depression right, right scapula marginally more dorsally, high state of pelvic right, iliac right further rotated anteriorly).ConclusionsHealthy young women have an almost ideally balanced posture with minimal ventral body inclination and a marginal scoliotic deviation. Compared with young males, women show only marginal differences in the upper body posture. These values allow a comparison to other studies, both for control and patient data, and may serve as guideline in both clinical practice and scientific studies.

scholarly journals Seat to Head Transmissibility during Exposure to Vertical Seat Vibration: Effects of Posture and Vibration Magnitude

2019 ◽  
Vol 24 (No 1) ◽  
pp. 3-11
Author(s):  
Mahesh K. Bhiwapurkar ◽  
V. H. Saran ◽  
Suraj P. Harsha
Keyword(s):  
Muscle Tension ◽  
Low Frequency ◽  
The Body ◽  
Body Motion ◽  
Upper Body ◽  
Head Motion ◽  
Softening Effect ◽  
Vibration Magnitude ◽  
Seat Vibration ◽  
Linear Softening

The low frequency vibration transmitted to the body can affect the comfort, performance, and health of humans. In this paper, the effect of variations in posture and vibration magnitude on the head motion in three translational axes (fore-and-aft, lateral and vertical) has been studied with a vertical seat vibration. Thirty healthy male subjects were exposed to random vibration with three vibration magnitudes of 0.4, 0.8, and 1.2 m/s2 rms over the frequency range of 1–20 Hz. The results are analysed in terms of seat-to-head-transmissibility (STHT) for the head motions in two seated postures (backrest and leaning forward on table). The measurement of the head motion was made with an apparatus (bite-bar) specifically developed for this purpose. The measured responses to a single axis seat vibration have also shown notable cross-axis responses in both vertical and fore-and-aft axes for both postures. The crossaxis fore-aft and vertical STHT responses showed single peak near 5 Hz in both postures. An increasing intensity of vibration yields a non-linear softening effect in the muscle tension, particularly in the presence of back support, however, the body stiffens under a greater upper body motion in the forward leaning posture. The combined effect of the unsupported back and hands support was observed to be more pronounced around the resonance peak in the forward lean posture.

scholarly journals The reliability of a restraint sensor system for the computer-supported detection of spinal stabilizing muscle deficiencies

2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Christian Pfeifle ◽  
Melanie Edel ◽  
Stefan Schleifenbaum ◽  
Andreas Kühnapfel ◽  
Christoph-Eckhard Heyde
Keyword(s):  
Sagittal Plane ◽  
Force Sensor ◽  
Training System ◽  
The Body ◽  
Upper Body ◽  
Good Test ◽  
Retest Reliability ◽  
Training Tool ◽  
Test Retest Reliability ◽  
And Training

Abstract Background The presence of muscular deficiency seems to be a major cause of back pain that requires counteractions. Considering that the autochthonous back muscles, responsible for straightening and stabilizing the spine, cannot be activated voluntarily, they can be strengthened only through specific training. The computer-supported test and training system (CTT) Centaur (BfMC GmbH, Leipzig, SN, Germany) seems well suited for this purpose. To show its potential as a reliable diagnostic and training tool, this study aimed to evaluate the test-retest reliability of this 3D spatial rotation device. Methods A prospective pilot study was conducted in 20 healthy volunteers of both sexes. For test-retest reliability analysis, three measurements were performed with a two-day interval between each measurement. Each measurement consisted of a one-minute endurance test performed in eight different positions (transverse plane). During the test, the subject was tilted by 90° in the sagittal plane from a neutral, upright position. Meanwhile, the subject’s level of upper body stabilization along the body axis was assessed. All trunk movements (momentum values) were quantified by a multicomponent force sensor and standardized relative to the subject’s upper body mass. The range of motion was assessed by 95% confidence ellipse analysis. Here, all position-specific confidence ellipses for each measurement were merged to a summarized quantity. Finally, ICC analysis using a single-rating, absolute agreement, two-way mixed-effects model and a Bland-Altman plot was performed to determine the reliability. Results Considering all measurements (t1, t2, t3), the ICC for reliability evaluation was 0.805, and the corresponding 95% confidence interval (CI) was [0.643, 0.910]. Moreover, the Bland-Altman plots for all three pairs of time points did not show significant differences. Conclusion This study concludes that the CTT Centaur shows good test-retest reliability, indicating it can be used in clinical practice in the future.

Body balance in a free-standing position in road and off-road cyclists

2014 ◽  
Vol 6 (4) ◽  
Author(s):  
Paulina Hebisz ◽  
Rafal Hebisz ◽  
Marek Zaton
Keyword(s):  
Sagittal Plane ◽  
Standing Position ◽  
The Body ◽  
Free Standing ◽  
Body Balance ◽  
Eyes Closed ◽  
Road Cycling ◽  
Progressive Exercise ◽  
Before And After ◽  
Road Cyclists

AbstractBackground: The purpose of this study was to compare body balance in road and off-road cyclists, immediately before and after the racing season.Material/Methods: Twenty individuals participated in the study and they were divided into two groups: specialists in road-cycling (n = 10) and in off-road cycling (n = 10). Immediately before and after the five-month racing season stabilographic trials were carried out (at rest and after progressive exercise). In assessing body balance the distance and velocity of the centre shifts (in the anterior-posterior and left-right direction) were analysed. The tests were performed with the cyclists’ eyes open, eyes closed, and in feedback.Results: After the racing season, in the off-road cyclists’ group, distance and velocity of the centre of pressure shifts increased after a progressive exercise.Conclusions: In the off-road cyclists’ group the balance of the body in the sagittal plane deteriorated after the racing season. Moreover, after the racing season off-road cyclists were characterized by a worse balance of the body, compared to road cyclists

Correction of Posture Deviations in the Sagittal Plane Using the Pilates Method

2019 ◽  
pp. 3-13
Author(s):  
Alexandru Cîtea ◽  
George-Sebastian Iacob
Keyword(s):  
Low Back Pain ◽  
Back Pain ◽  
Postural Control ◽  
Human Body ◽  
Sagittal Plane ◽  
The Body ◽  
Lower Limbs ◽  
Low Back ◽  
Pilates Method ◽  
The Relationship

Posture is commonly perceived as the relationship between the segments of the human body upright. Certain parts of the body such as the cephalic extremity, neck, torso, upper and lower limbs are involved in the final posture of the body. Musculoskeletal instabilities and reduced postural control lead to the installation of nonstructural posture deviations in all 3 anatomical planes. When we talk about the sagittal plane, it was concluded that there are 4 main types of posture deviation: hyperlordotic posture, kyphotic posture, rectitude and "sway-back" posture.Pilates method has become in the last decade a much more popular formof exercise used in rehabilitation. The Pilates method is frequently prescribed to people with low back pain due to their orientation on the stabilizing muscles of the pelvis. Pilates exercise is thus theorized to help reactivate the muscles and, by doingso, increases lumbar support, reduces pain, and improves body alignment.

Toughness

2009 ◽  
pp. 536-548
Author(s):  
Richard A. Dienstbier ◽  
Lisa M. Pytlik Zillig
Keyword(s):  
The Body ◽  
Positive Outcomes ◽  
Adaptive Coping ◽  
Dynamic Interactions ◽  
Abstract Level ◽  
The Central Nervous System ◽  
Cortical System ◽  
The Mind ◽  
And Training ◽  
Neuroendocrine Systems

This chapter presents an overview of the concept of toughness, which at the abstract level is about the harmony of physiological systems, and more concretely is about how the body influences the mind. Toughness theory begins with the recognition that there is a “training effect” for neuroendocrine systems. Following a review of the characteristics of interventions and training programs that can promote toughness, the authors present a model in which the effects of toughness are mediated by neuroendocrine systems such as the pituitary-adrenal-cortical system and the central nervous system. The elements of toughness (e.g., having a greater capacity for arousal and energy when needed) are proposed to promote positive outcomes by facilitating the use of adaptive coping strategies and improving emotional stability. Toughness therefore appears to be a promising concept within positive psychology in that it helps to explain how the dynamic interactions between psychological and somatic processes can promote positive outcomes.

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