Wyniki wyszukiwania - BazTech

1

A comparison of the stability of standing shooting stance in expert and novice mountain infantry shooters

Ratajczyk Mariusz, Homańczuk Arkadiusz, Pacześny Sławomir, Sobera Małgorzata

Scientific Journal of the Military University of Land Forces

|

2023

|

Vol. 55, No. 1(207)

33--42

EN

This study compares balance control in standing shooting stance in expert and novice military shooters among mountain infantry soldiers. Balance control was assessed using AccuSway (AMTI, USA) force platforms in terms of the range of the centre of pressure (COP) displacements in the mediolateral (RANGE(ML)) and anteroposterior direction (RANGE(AP)), the standard deviation of COP displacements in the mediolateral (SD(ML)) and anteroposterior direction (SD(AP)), the sway area of COP displacements (ELLIPSE), the average velocity of COP displacements (AVG VEL) and the COP path length (LENGTH). The participants (expert shooters, N=10; novice shooters, N=15) adopted tactical standing shooting stance wearing the field uniform, with a rifle on force platforms (one for each lower limb), over a period of 10 seconds, with sampling frequency of 100Hz. The statistical analysis using the Mann-Whitney U test revealed a significant difference between the studied groups, taking into account the ELLIPSE and the AVG VEL variables values for the dominant leg only. It was concluded that the expert shooters showed better stability than novice shooters. This study presents implications regarding biomechanical aspects of standing shooting stance stability.

PL

Celem pracy jest porównanie jakości procesu kontroli równowagi w postawie strzeleckiej stojąc doświadczonych i początkujących strzelców piechoty górskiej. Kontrolę równowagi oceniono za pomocą platform sił AccuSway (AMTI, USA) pod względem wartości miar stabilności obliczonych na podstawie przebiegu punktu przyłożenia wypadkowej siły reakcji na podłoże – COP (ang. Center of Pressure), w tym: zakresu przemieszczeń w kierunku przyśrodkowo-bocznym (RANGE(ML)) i przednio-tylnym (RANGE(AP)), odchylenia standardowego przemieszczeń COP w kierunku przyśrodkowo-bocznym (SD(ML)) i przednio-tylnym (SD(AP)), pola elipsy przemieszczeń COP (ELLIPSE), średniej prędkości przemieszczeń COP (AVG VEL) oraz długości ścieżki COP (LENGTH). Uczestnicy (doświadczeni strzelcy, N=10, początkujący strzelcy, N=15) przyjęli taktyczną postawę strzelecką stojąc w umundurowaniu polowym z karabinkiem Beryl wz. 96 na platformach sił (po jednej dla każdej kończyny dolnej) przez okres 10 sekund, z częstotliwością próbkowania ustawioną na 100Hz. Analiza statystyczna przeprowadzona za pomocą testu U Manna-Whitneya wykazała istotną różnicę pomiędzy badanymi grupami w wartościach wskaźnika pola elipsy (ELLIPSE) oraz średniej prędkości przemieszczeń COP (AVG VEL) jedynie dla dominującej kończyny dolnej. Stwierdzono, że doświadczeni strzelcy charakteryzują się większą stabilnością przyjętej postawy strzeleckiej niż początkujący strzelcy. W pracy przedstawiono implikacje dotyczące biomechanicznych aspektów stabilności postawy strzeleckiej stojąc.

2

Balance control via tactile biofeedback in children with cerebral palsy

Argunsah Hande, Yalcin Begum

Acta of Bioengineering and Biomechanics

|

2023

|

Vol. 25, no. 1

161--171

EN

Children with cerebral palsy have limitations in utilizing neural information to perform smooth movement and maintain balance during walking. This study aimed to develop a wearable sensor that tracks balance continuously and provides haptic biofeedback to its user through real-time vibration stimulus to assist patients with balance and postural control impairments such as cerebral palsy. Methods: Twelve children with cerebral palsy and 12 age-matched typically developed children used the sensor during walking at a self- -selected speed. The lower extremity joint kinematics, center of mass, and spatial-temporal parameters were recorded with Xsens MVN during “with” and “without” biofeedback conditions. Results: The sensor did not disturb healthy gait. Pearson correlation coefficient and Root Mean Square Error techniques showed that biofeedback regulated the gait parameters and trunk stability of the CP group. The extended stance percentage (without BF: 73.91% ± 10.42, with BF: 63.53% ± 2.99), step width (without BF: 0.20 m ± 0.05, with BF: 0.18 m ± 0.07), and step time (without BF: 1.55 s ± 1.07, with BF: 0.73 s ± 0.14) parameters decreased. Similarly, cadence and walking speed increased. Conclusions: Obtained results indicated that this wearable sensor can be integrated into the physical therapy and rehabilitation process of children with balance and postural control impairments to improve motor learning and balance control. The present findings contribute to a better understanding of the adaptation of innovative engineering applications with rehabilitation processes, which, in turn, could assist patients with balance impairments and facilitate their integration into society.

3

EEG based cortical investigation for the limit of stability analysis in transfemoral amputees: A comparison with able-bodied individuals

Khajuria Aayushi, Joshi Deepak

Biocybernetics and Biomedical Engineering

|

2022

|

Vol. 42, no. 1

362--374

EN

Background: The evidences for demonstrating the contributions of the cerebral cortex in human postural control is increasing. However, there remain little insights about the cortical correlates of balance control in lower-limb amputees. The present study aimed to investigate the cortical activity and balance performance of transfemoral amputees in comparison to healthy individuals during a continuous balance task (CBT). Methods: The postural stability of the participants was defined with limit of stability parameter. Electroencephalography (EEG) data were recorded in synchronization with the center of pressure (CoP) data from eighteen individuals (including eight unilateral transfemoral amputees). We anticipated that, due to the limb loss, the postural demand of transfemoral amputees increases which significantly modulates the spectral power of intrinsic cortical oscillations. Findings: Using the independent components from the sensorimotor areas and supplementary motor area (SMA), our results present a well-pronounced drop of alpha spectral power at sensorimotor area contralateral to sound limb of amputees in comparison to SMA and the sensorimotor area contralateral to prosthetic limb. Following this, we found significantly higher (p < 0.05) limit of stability (LOS) at their sound limb than at the prosthetic limb. Healthy individuals have similar contribution from both the limbs and the EEG alpha spectral power was similar across the three regions of the cortex during the balance control task as expected. Overall, a decent correlation was found between the LOS and alpha spectral power in both amputee and healthy individuals (Pearson’s correlation coefficient > 0.5). Interpretation: By externally stimulating the highlighted cortical regions, neuroplasticity might be promoted which helps to reduce the training time for the efficient rehabilitation of amputees. Additionally, this new knowledge might benefit in the designing and development of innovative interventions to prevent falls due to lower limb amputation.

4

Immediate after-effects of shapes of clothing worn on tandem gait performance

Oshita Kazushige

Acta of Bioengineering and Biomechanics

|

2021

|

Vol. 23, no. 3

79--85

EN

Purpose: This study investigated the immediate after-effects of clothing shape on tandem gait performance. Methods: Nineteen healthy men (21.8 ± 1.8 years) performed tandem gait tests while blindfolded under three clothing conditions: only half or short tights, a cotton cloth wrapped around the waist and draped to the middle point of the lower leg (DC), and tracksuit bottoms (TS). Participants performed pre- and post-gait tests at their fastest possible speed while wearing tights. Between the pre- and post-tests, participants practiced the same tandem gait, but at their own chosen speed while wearing DC or TS. Results: The practice with the DC increased gait speed and decreased lateral shift during the post-gait test compared to the pre-gait test. The practice while wearing the TS also reduced lateral shift but did not increase gait speed. Conclusions: These results suggest that some clothing shapes are more effective for motor learning of balance control during tandem gait by enhancing the feedback for body orientation. Clothing that has a certain amount of space between the material and the body and that makes contact with the body as it moves may be more effective.

5

Gender differences of the improvement in balance control based on the real-time visual feedback system with smart wearable devices

Wang I-Lin, Wang Li-I, Xue Shi-Jie, Hu Rui, Jian Rong-Jiun, Ho Chun-Sheng

Acta of Bioengineering and Biomechanics

|

2021

|

Vol. 23, no. 1

163--171

EN

Purpose: The body maintains stability by integrating inputs from the central nervous system of vision, hearing, proprioception, and multiple senses. With the development of smart wearable devices, smart wearable devices can provide real-time center of pressure position-assisted balance control, which is beneficial to maintain physical balance. Methods: Forty healthy college students (20 male, 20 female) participated in this study, and the posture balance actions of left-leg stance non-visual feedback, left-leg stance visual feedback, right-leg stance non-visual feedback, and right-leg stance visual feedback were performed. Visual feedback provided smart insoles matching Podoon APP on a tablet computer with the COP position displayed by a dot as real-time visual feedback. Results: The experimental results show that the displacement, velocity, radius, and area of the COP decreased significantly in the left-leg stance visual feedback/right-leg stance visual feedback, the test compared the parameters in the left-leg stance non-visual feedback/right-leg stance nonvisual feedback (P < 0.05). Providing visual feedback through intelligent insoles can reduce the movement of the center of mass and maintain physical stability for healthy young people of different genders. In the one leg visual/non-visual in standing, the COP maximum anteroposterior displacement, COP anteroposterior velocity, COP radius, and COP area in women are significantly smaller than in men (P < 0.05). Women have better real-time balance control ability than men with smart insoles. Conclusions: The simple intelligent wearable assisted devices can immediately increase the control ability in static stance of men and women, and women have better real-time balance control ability than men.

6

Influence of changing frequency and various sceneries on stabilometric parameters and on the effect of adaptation in an immersive 3D virtual environment

Jurkojc J., Wodarski P., Bieniek A., Gzik M., Michnik R.

Acta of Bioengineering and Biomechanics

|

2017

|

Vol. 19, no. 3

129--137

EN

Purpose: The aim of the study was to examine the influence of different types of virtual sceneries and frequencies of movement of visual disturbances on stabilometric values as well as whether individual sceneries and changing frequency can minimize effect of adaptation of tested person to applied disturbances. Methods: There were 23 healthy participants. A person has been standing on a Zebris stabilometric platform. Virtual 3D environment was displayed by means of HMD Oculus Rift system. An open (a meadow) and closed (a room) sceneries were used. The sceneries moved along the sagittal axis and rotated around horizontal axis. The measurement lasted 30 seconds and in the middle of it frequency of translational movement was changed from 0.7 Hz to 1.4 Hz or from 1.4 Hz to 0.7 Hz. Results: The data were reported as medians of COP velocity and ellipse area. Visual disturbances caused the increase of these values in comparison with the tests conducted with open eyes. Results divided into periods (the first and the second 15 seconds) showed that in the first half of the test values were higher compared to the second half. The comparison of values obtained for open and closed scenery showed that higher values were recorded for open scenery. Conclusions: The comparison of both types of sceneries on the basis of COP velocity and ellipse area showed that open scenery had a greater impact on the measured stabilometric values. It was found out as well that people got accustomed to the applied disturbances, but this effect was lower in the open scenery.