Measurement of Force Impact Taekwondo Athletes, Assessing the Possibility of Injury of Human Head

AbstractThe article presents the results of measurements impact taekwondo athletes to the board which opens after hitting stroke. Measured values are compared with the results of scientific studies that dealt with human head injuries due to the impacts of various kinds. Most often, these results were determined using cadavers bodies. Force action of the athletes on board was realized by direct punches which are combat sport led to facial parts of opponent. In their own measurement was determined time course of forces impinging on the dynamometer plate including size and direction of the force. Dynamometer measured forces to 10000 N. The frequency was set to 1000Hz. Estimate of accuracy was 0.5% of measured value. A composite plate was attached to a dynamometer using special steel structures. When comparing the results was found that the combat sport of taekwondo strikes, including other power effects (eg. others combat sports, falls, blows to the head in accidents, etc.) can cause fractures of the facial bones and even other human head trauma or cervical vertebrae

UŽITÍ BIOREOMETRIE KE SLEDOVÁNÍ LÉČBY PORUCH KOLENNÍHO KLOUBU

BIORHEOMETRY AS DETECTION TOOL OF THE THERAPY OF THE KNEE JOINT DEFECTS. The apparatus called biorheometer has been constructed at the Faculty of Physical Education and Sport of the Charles University in Prague. The apparatus demonstrate the biorheological properties of the knee joint by a non-invasive method. It has been used for the control of the surgery eff ect and rehabilitation of the rupture of the ligament cruciate anterior and the knee cartilage defects. Description of the biorheometer, its function, and examples of the obtained biorheographs are given in the article

Changes of Rheological Properties During Various Degrees of Knee Flexion after Meniscectomy

Aim of this article is to find out if there is any difference in rheological properties in various degrees of flexion in the knee with meniscal tear and compare the results with measurement after physical activity. Experimental measurements were done by using the method of biorheometry which detects the passive resistance of the knee in movement from flexion to extension. We found changes of rheological properties in higher degrees of knee flexion with typical rising followed by fall of biorheogram around flexion of 80°. They were more remarkable after physical activity. Changes of rheological properties were more expressive in patients who have undergone meniscectomy a few years ago than changes in patients with recent meniscectomy

Differences in kinematics of the support limb depends on specific movement tasks of take-off

Background: Many sport activities are a sequence of jumps (running, jumping, hurdling etc.). Each jump flight phase is the result of the execution of the previous support phase. Objective: The goal of the research was to identify differences in adjustment of the support lower limb and differences in take-off kinematics in specific take-off movement task. Methods: 14 male athletes (22.6 ± 4.4 years; 182.4 ± 5.3 cm; 74.7 ± 6.2 kg) took part in a laboratory experiment. Each athlete performed five different take-off movements (running, acceleration running - second step, long jump take-off, high jump take-off and take-off to the hurdle). System Qualisys was used to analyze the kinematics of the support limb. Dynamics of the support phase was monitored via force plate. ANOVA and Bonferroni post-hoc test were used to measure the significance of the differences between different take off tasks. Results: Dynamic characteristic showed significant differences in take-off (p < .001). This variability is caused by differences in kinematic parameters at the instant of touch-down, minimum joint angles and take-off. The most important finding was different variability in range of motion in eccentric or concentric phases of each jump. Vertically orientated jumps are terminated in a higher degree of extension. Horizontal take-off types are characterized by the highest ranges of motion especially in the ankle joint. Conclusions: The support lower limb compliance is adjusted to the required task, which is related to lower limb kinematics during the support phase. High range of motion in each joint refers to more compliant adjustment of the joint

The effect of military boots on front kick dynamics

Front kicks are often used in combat activities that involve the use of kicks and punches, including close combat military training. To mimic real-life combative environments where soldiers execute forceful front kicks while wearing military boots, it is logical to wear these boots during close combat training. However, the effect of military footwear on front kick forces remain unknown. Therefore, the aim of this study was to compare the effects of military boots on front kick dynamics. Six male soldiers (23.3 ± 1.7 yr, 74.3 ± 6.2 kg, 175.5 ± 4.5 cm) performed eight individual front kicks with no military boots, in bare feet (NB) and with military boots (MB). Peak force (N), impulse (N.s) and time to reach peak force (ms), were measured during each kick. Data were analyzed using paired sample t-tests or nonparametric Wilcoxon pair test and Cohen’s d. Results. Neither peak force (3180 ± 647 N) nor impulse (367 ± 40 N.s) of MB were different than NB (3157 ± 291 N and 360 ± 48 N.s, respectively) (p = 0.85; d = 0.04 and p = 0.36; d = 0.12, respectively). Peak force was reached in a significantly shorter time during MB (39 ± 16 ms) compared to NB (56 ± 8 ms; d = −0.88). Conclusion. Peak force was reached in a shorter time using MB compared to barefoot (NB) front kicks. The use of military boots changes the time course of peak force during the front kick

Load Measurement of the Cervical Vertebra C7 and the Head of Passengers of a Car While Driving across Uneven Terrain

The article deals with the measurement of dynamic effects that are transmitted to the driver (passenger) when driving in a car over obstacles. The measurements were performed in a real environment on a defined track at different driving speeds and different distributions of obstacles on the road. The reaction of the human organism, respectively the load of the cervical vertebrae and the heads of the driver and passenger, was measured. Experimental measurements were performed for different variants of driving conditions on a 28-year-old and healthy man. The measurement’s main objective was to determine the acceleration values of the seats in the vehicle in the vertical movement of parts of the vehicle cabin and to determine the dynamic effects that are transmitted to the driver and passenger in a car when driving over obstacles. The measurements were performed in a real environment on a defined track at various driving speeds and diverse distributions of obstacles on the road. The acceleration values on the vehicle’s axles and the structure of the driver’s and front passenger’s seats, under the buttocks, at the top of the head (Vertex Parietal Bone) and the C7 cervical vertebra (Vertebra Cervicales), were measured. The result of the experiment was to determine the maximum magnitudes of acceleration in the vertical direction on the body of the driver and the passenger of the vehicle when passing a passenger vehicle over obstacles. The analysis of the experiment’s results is the basis for determining the future direction of the research

Low Concentrated Fractionalized Nanofibers as Suitable Fillers for Optimization of Structural–Functional Parameters of Dead Space Gel Implants after Rectal Extirpation

Dead space after rectal resection in colorectal surgery is an area with a high risk of complications. In this study, our goal was to develop a novel 3D implant based on composite hydrogels enriched with fractionalized nanofibers. We employed, as a novel approach in abdominal surgery, the application of agarose gels functionalized with fractionalized nanofibers on pieces dozens of microns large with a well-preserved nano-substructure. This retained excellent cell accommodation and proliferation, while nanofiber structures in separated islets allowed cells a free migration throughout the gel. We found these low-concentrated fractionalized nanofibers to be a good tool for structural and biomechanical optimization of the 3D hydrogel implants. In addition, this nano-structuralized system can serve as a convenient drug delivery system for a controlled release of encapsulated bioactive substances from the nanofiber core. Thus, we present novel 3D nanofiber-based gels for controlled release, with a possibility to modify both their biomechanical properties and drug release intended for 3D lesions healing after a rectal extirpation, hysterectomy, or pelvic exenteration