THE VOLLEYBALL APPROACH: AN EXPLORATION OF RUN-UP LAST STRIDE LENGTH WITH JUMP HEIGHT AND DEVIATION IN LANDING

The main aim of present research was to find out a significant correlation between approach run-up last stride length and the height of jump and landing deviation. Fourteen top elite volleyball players have been served for this study. A Mikro-Mak Motion Analyzer with Win-Analyze program has been used for this study. A Philips video camera with 240 frames per second has also been used to better trace the markers on the shoulder, hip, knee, ankle, and toe. The program enabled us to find out the displacement and velocity of all parts and especially the toes’ in order to measure the different last stride lengths and the deviation from vertical axis. Although we were expecting to get a significant correlation between this parameter and jump height, as in long stride the CG is displaced in longer range with higher horizontal motion than when the player jumps with shorter stride, but the findings did not support this idea. The results are given in Tables 1-4

Improvement in Performance of a Thermochemical Heat Storage System by Implementing an Internal Heat Recovery System

A lab-scale prototype of a thermochemical heat storage system, employing a water-zeolite 13X as the working pair, is designed and optimized for providing hot tap water. During the hydration process, humid air is introduced to the packed bed reactor filled with dehydrated zeolite 13X, and the released heat of adsorption heats up the air passing through the reactor. The hot outflow air is led to an air-to-water heat exchanger integrated in a water tank and heats up the water. The residual heat in the exhaust air is used to preheat the reactor inflow in an air-to-air heat exchanger. The temperatures of all system components are measured, and the thermal powers and heat losses are calculated. Experiments are performed in the system with and without using the heat recovery, and improvement in performance of the heat storage system is investigated

Design and Implementation of an IMU Sensor System to Estimate a Hockey Puck’s Peak Velocity

The rapid advancement in sensor technology can revolutionize how sports dynamics are understood and analyzed. This thesis focuses on designing and implementing an Inertial Measurement Unit (IMU) sensor system to be deployed within a hockey puck to estimate its peak velocity. The research involved the intricate design of a sensor system comprising an accelerometer, two gyroscopes, and a magnetometer. Moreover, puck preparation was carried out to secure the sensor and battery within the puck to ensure functionality and durability. Furthermore, a data acquisition system is developed to receive, save, and plot data transmitted via Bluetooth Low Energy (BLE) protocol. Three distinct methods for estimating the puck's peak velocity from the sensor data are compared. It is discovered that the method based on an extended Kalman filter and utilizing data from all three sensor types exhibits superior accuracy. This method is subsequently validated under various hockey shot conditions, reinforcing its practical applicability. Moreover, the relationship between velocity estimation error versus true velocity is investigated. Primarily designed for research studies, this work offers a foundational understanding of hockey puck dynamics, despite the sensor system not being tailored for real-game scenarios. The insights gained have substantial implications for further sports analytics and player training. Furthermore, the results outline a promising pathway for future sports engineering and wearable technology investigations

The short time effect of spirulina supplementation on some oxidative stress markers of elite endurance cyclist

Background and aims: The aim of this study was to investigate short time effect of spirulina supplementation on serum malondialdehyde (MDA) and superoxide dismutase (SOD) level. Methods: The study design was quasi experimental with pre and post-test. For this reason, 14 male endurance cyclist (age 20.5±1.4, height 180.21±4.33, weight 66.4±2.16, BMI 20.22±0.7, VO2Max 71.78±2.93) that they are/were member of Iran national team were selected as participant. 1 week before test, Participants were asked to stop all supplements consumption containing vitamins and minerals which they have been using. Resting Blood sample were taken of fasting, for assessing research variable at least 18 hours after last their training session. After exhaustive exercise and body composition assessment at pretest, participates were derived into 2 groups, based on BMI (Spirulina group n=7, control group n=7). Participants used supplements in same way and same principle (6×500mg tablet per day) for 2 weeks. After 2 weeks supplementation, blood sample was taken for resting value of MDA and SOD. Results: Between and within groups analysis demonstrated significant increase in SOD and MDA levels under effect of exercise and 2 weeks spirulina supplementation reduced and increased significantly MDA levels (P<0.05) and SOD levels (P<0.05) at rest and after exhaustive exercise- in Spirulina group in comparison with placebo group. Conclusion: According to results, 2 weeks of spirulina supplementation can reduce oxidative stress in elite endurance cyclist

THE RELATIONSHIP BETWEEN THE LACTATE TURNPOINT AND THE TIME AT VO2 max DURING A CONSTANT VELOCITY RUN TO EXHAUSTION

The aim of present work was to examine the relationship between the running velocity at the lactate turn-point (vLTP) and the time at which VO can be sustained (TVO ) during a continuous run to exhaustion at a minimal running velocity that yields VO (vVO ). Pearson’s correlation coefficient was used to determine the association between vLTP and TVO and between other selected physiological variables. Correlations between the relative vLTP and v VO was significant (r=0.63) at the

Design of a thermochemical heat storage system for tap water heating in the built environment

Replacing the use of fossil fuel by solar energy, as one of the most promising sustainable energy sources, is of high interest, because of climate change and depletion of fossil resources. However, to reach high solar fractions and to overcome the mismatch between supply and demand of solar heat, storage of solar energy is necessary. A reliable method for long term heat storage is to use thermochemical materials, TCMs. The heat storage process is based on a reversible adsorption-desorption reaction of water vapor on the TCM, which is exothermic in one direction and endothermic in the reverse direction. In this research, Zeolite 13X is used as TCM. The system is an open sorption heat storage system for providing hot tap water. In the experimental test setup, the humid air is provided in a bubble column by blowing air from bottom of the column. The exothermic hydration process starts with humid air entering into a packed bed reactor filled with zeolite 13X. The reactor is a vertical cylindrical tank which is made of steel; it has a layer of Teflon inside and has a layer of insulation outside. The temperature profile in the reactor is measured as a function of time both along the flow direction and perpendicular to the flow by thermocouples. In addition, input and output temperatures and humidity are measured. In the resulting adsorption reaction between water vapor and TCM, energy is released. This released energy heats up the air flow which passes through the reactor and the hot output air flow is used to heat up the water in a water tank. The water tank is also a vertical cylindrical tank which is made of steel and has a layer of insulation outside. The hot output air from the reactor passes through a coiled tubing inside the water tank to heat up water. The temperature of the water in the tank is measured at two different heights. A problem in open solid sorption systems using air as heat transport medium is the limited temperature step which can be achieved in the sorption bed. In the present study this problem is solved using a heat recovery system enabling higher output air temperatures. The residual heat in the exhaust air is used to preheat the reactor inflow, in an air-to-air heat exchanger. In the endothermic dehydration process, the hydrated zeolite is dried with hot air. In this study, a lab-scale prototype TCM based heat storage system is designed and optimized, which, by making use of a heat recovery loop, is able to provide hot tap water. Results of the experimental investigation on charge-discharge cycles will be presented.<br/

The short time effect of spirulina supplementation on some oxidative stress markers of elite endurance cyclist

Background and aims: The aim of this study was to investigate short time effect of spirulina supplementation on serum malondialdehyde (MDA) and superoxide dismutase (SOD) level. Methods: The study design was quasi experimental with pre and post-test. For this reason, 14 male endurance cyclist (age 20.5±1.4, height 180.21±4.33, weight 66.4±2.16, BMI 20.22±0.7, VO2Max 71.78±2.93) that they are/were member of Iran national team were selected as participant. 1 week before test, Participants were asked to stop all supplements consumption containing vitamins and minerals which they have been using. Resting Blood sample were taken of fasting, for assessing research variable at least 18 hours after last their training session. After exhaustive exercise and body composition assessment at pretest, participates were derived into 2 groups, based on BMI (Spirulina group n=7, control group n=7). Participants used supplements in same way and same principle (6×500mg tablet per day) for 2 weeks. After 2 weeks supplementation, blood sample was taken for resting value of MDA and SOD. Results: Between and within groups analysis demonstrated significant increase in SOD and MDA levels under effect of exercise and 2 weeks spirulina supplementation reduced and increased significantly MDA levels (P<0.05) and SOD levels (P<0.05) at rest and after exhaustive exercise- in Spirulina group in comparison with placebo group. Conclusion: According to results, 2 weeks of spirulina supplementation can reduce oxidative stress in elite endurance cyclist

Healthful characteristics of pennyroyal essential oil

Pennyroyal, an aromatic herb, is considered by food and medicine industries. It grows in different countries and provides various technological and functional properties. Essential oils (especially ‘Pulegune’) are the effective materials of pennyroyal that causes anti-microbial, anti-oxidant and aromatic properties. These essential oils have significant effects on preventing growth of several species of pathogenic and spoilage bacteria. Furthermore, these oils maintain food quality by preventing the oxidation of fatty acids and increasing product shelf life. Therefore, it seems that pennyroyal is an appropriate alternative for synthetic antioxidants. On the other hand, it can be used in treatment from medicinal point of view. Overall, pennyroyal essential oils are a good, natural and economical alternative for food and medicine industries. The present article focuses on the healthful and technological characteristics of pennyroyal essential oils

Effect of Zinc supplementation on serum testosterone and plasma lactate in male cyclist after one bout of exhaustive exercise

Background and aims: There is fairly scarce information about the effects of zinc, an essential trace element, on exercise performance. Studies concentrate mostly on the distribution of this element in the body in response to exercise. The purpose of this study was to investigate the effect of exhaustion exercise on the testosterone levels and plasma lactates in road cyclists who are supplemented with oral zinc for 4 weeks. Methods: In this semi experimental sixteen male road cyclists, who were healthy in the first evaluation were selected from the Tehran traffic team and were divided into two groups according to mass body index zinc group and control group. After 4 weeks zinc supplementation (30 mg/day), blood samples were collected from each subject before and after an exhaustive exercise bout. Data were analyzed by independent and paired sample t test. Results: Total testosterone, free testosterione and lactate levels in two groups were increased by exercise (P0.05). There was a significant difference between effects of exhaustion exercise on free testosterone levels between two groups (P<0.05). Conclusion: According to this study, zinc supplementation has no significant effects on testosterone and lactate levels in response to exercise in subjects with a balance diet. However, free testosterone levels were increased by exercise after zinc supplementation