ANALYSIS OF HIGH-SPEEDRUNNING AND SPRINT RUNNING IN ELITE FEMALE FOOTBALL COMPETITIONS

Introduction: Although football is recognized as the fastest growing sport globally, scientific literature on female footballis still limited. Available published data in understanding the physical demands of female football players have described the necessity of a high level of physical conditioning during matches with average heart rates of 84-86% maximum heart rate and an average of 9.1-11.9 km in total distance covered in the running. The most commonly utilized physical performance measures reported are high-speed running (19km/h-23km/h) and sprinting (>23 km/h). A better understanding of football's physical, technical and tactical demands has resulted from investigations of both training and matches by wearing a global positioning system unit.Objective: This study aimed to assess the running speed and the proportions of different types of running during official competitions in elite female football players.Material and Method: A total of 22 female players (16 seniors and six juniors) that are part of a Romanian First League female football team -Politehnica Timisoara, have been monitored for running speed and covered distance in 6 official matches, which represent a quarter of the championship period. The assessment period was ten weeks (August-October 2021). The monitored parameters (total distance, distance/minute, low speed running, high speed running, sprint running, and maximum speed) wereobtained using K-Sport GPS with a high sampling rate of 50 Hz.Results: During the six analyzed matches the following average values were found: total covered distance -7906.33 ± 1176.68 m, distance/minute -90.83 ± 3.72 m/min, low-speed running distance-7598.50 ± 1102.16 m, high-speed running distance -308 ± 101.31 m, sprint running distance -69.50 ± 28.54 m, and maximum speed -25.13 ± 0.84 km/h.Conclusion: Regarding the monitored parameters (total distance, average speed, proportion of different speed running, maximum speed), we observed a constancy between different matches. During female football matches, high-speed running and sprinting covered 4.77% of the total distance. Based on this data, a future training objective would be the enhancement of this percentage in order to optimize the key moments of the matches.

Mathematical model of the influence of the time of start reaction in 100 m sprint run

The purpose of this study is to explain the influence of the time of start reaction tR to the results of sprinters in a 100 m run, using a new simple mathematical model based on the measured values for distance s, corresponding time t, and tR. The research is based on IAAF data obtained by measuring the segment length, the time of start reaction, transient times in 100 m run, and final times for the top sprinters C. Lewis (1988); M. Green (2011), and U. Bolt (2009) (men) and F. Griffith-Joyner (1988); E. Ashford (1988), and H. Drechsler (1988) (women). The values of the start reaction tR for both male and female top sprinters indicate that there appear no substantial differences in the values of tR based on gender which would directly favor male or female sprinters in achieving the top results in the 100m run. The influence of the time of start reaction tR decreases exponentially with the time t during the run (t>tR) and ends up at about 30 m, influencing the initial velocity vR although it is not directly related to the result of the run. Due to its applicative simplicity, the presented mathematical model and related conclusions can represent a solid basis for future studies concerning sprint running.

Maintenance of ankle power and decreased inter-limb asymmetry during sprint running in fatigued multi-speed athletes

The ability to shift from walking and jogging to sprinting gaits, even when fatigued after prolonged effort, would have been as useful to our hunter-gatherer ancestors as it is in modern day sports. During prolonged jogging, joint moment and work are reduced in the distal (ankle) joint but increased at proximal (hip/knee) joints as fatigue progresses, and might be expected to occur in sprinting. Fatigue is also thought to increase inter-limb kinematic and force production asymmetries, which are speculated to influence injury risk. However, the effects of running-related fatigue on sprint running gait have been incompletely studied, so these hypotheses remain untested. We studied 3-D kinematics and ground reaction force production in dominant (DL) and non-dominant (NDL) legs during both non-fatigued and fatigue sprinting in habitual but uncoached running athletes. Contrary to the tested hypotheses, relative between-leg differences were greater in non-fatigued than fatigued sprinting. When not fatigued, DL produced greater propulsive impulse through both greater positive and negative work being performed at the ankle, whilst NDL produced more vertical impulse, possibly resulting from the greater hip flexion observed prior to the downwards acceleration of the foot towards the ground. Whilst few changes were detected in DL once fatigued, NDL shifted towards greater horizontal force production, largely resulting from an increase in plantarflexion (distal-joint) moments and power. After fatiguing running, therefore, inter-limb asymmetry was reduced and no distal-to-proximal shift in work/power was detected during sprinting. Speculatively, these adaptations may help to attenuate decreases in running speed whilst minimising injury risk.

Impact of Possession and Player Position on Physical and Technical-Tactical Performance Indicators in the Chinese Football Super League

The purpose of this study was to investigate the impact of high (HPBPT) and low percentage ball possession teams (LPBPT) on physical and technical-tactical performance indicators in the Chinese Football Super League (CSL). Eight physical performance indicators and 26 technical-tactical performance indicators from all 240 matches from season 2018 were analyzed, as well as three contextual variables (team strength, quality of opposition, and match location). Players were divided according to five positions: fullbacks, central defenders, wide midfielders, central midfielders, and attackers. A k-means cluster analysis was conducted to classify all match observations into two groups: HPBPT (n = 229) and LPBPT (n = 251). A mixed linear model was fitted with contextual variables as covariates. When significant interactions or main effects were detected, a post hoc comparison was used to compare physical and technical/tactical differences between HPBPT and LPBPT. Results showed that central defenders and fullbacks covered more high-intensity and sprint running distance in the high possession teams, while wide midfielders and forward covered more high-intensity and sprint running distance in the low possession teams. Meanwhile, players from high ball possession teams were strong in technical indicators, especially in attacking organization. These results may help coaches to understand current football development trends and develop suitable training plans and tests for elite football players.

Validity of a Magnet-Based Timing System Using the Magnetometer Built into an IMU

Inertial measurement units (IMUs) represent a technology that is booming in sports right now. The aim of this study was to evaluate the validity of a new application on the use of these wearable sensors, specifically to evaluate a magnet-based timing system (M-BTS) for timing short-duration sports actions using the magnetometer built into an IMU in different sporting contexts. Forty-eight athletes (22.7 ± 3.3 years, 72.2 ± 10.3 kg, 176.9 ± 8.5 cm) and eight skiers (17.4 ± 0.8 years, 176.4 ± 4.9 cm, 67.7 ± 2.0 kg) performed a 60-m linear sprint running test and a ski slalom, respectively. The M-BTS consisted of placing several magnets along the course in both contexts. The magnetometer built into the IMU detected the peak-shaped magnetic field when passing near the magnets at a certain speed. The time between peaks was calculated. The system was validated with photocells. The 95% error intervals for the total times were less than 0.077 s for the running test and 0.050 s for the ski slalom. With the M-BTS, future studies could select and cut the signals belonging to the other sensors that are integrated in the IMU, such as the accelerometer and the gyroscope.

Determining the Prognostic Validity of the Unilateral Horizontal Cyclic Jumps Test in Sprint Performance

In sports practice, motor tests are commonly used to predict success in specific segments of sprint running, as well as post-injury tests in rehabilitation. The purpose of this analytical cross-sectional study was to determine the prognostic validity of the unilateral horizontal cyclic jumps for a 20 m (UHCJ20m) test on sprint running success. A sample of 118 kinesiology students aged 20.5 ± 1.2 years with an average height of 179.7 ± 6.4 cm and a body mass of 75.6 ± 7.3 kg was used to determine the correlation between the results of the UHCJ20m test and the results of the 20 m sprint start run (MRLS20m), the 20 m sprint flying start run (MRFS20m), and the 100 m run (M100m). The results showed a moderate correlation in all tests (MRLS20m (R = 0.49), MRFS20m (R = 0.53), and M100m (R = 0.38)) with UHCJ20m. In addition to the final result, the multiple regression analysis showed a significant moderate correlation between the kinematic parameters of the UHCJ20m test and the results in the MRLS20m (R = 0.38), MRFS20m (R = 0.49), and M100m (R = 0.37) tests. The stride length (SL) and the contact time (CT) of the UHCJ20m test were statistically significant predictors for the 100 m sprint, the number of steps for MRLS20m, and the SL and the CT for MRFS20m sprint success. Unilateral horizontal cyclic jumps are a significant predictor of success in sprint running, especially for the maximal speed running segment.

Effect of Parachute Running Training on 100 Meter Sprint Running Speed

This study aims to determine how much influence the parachute running exercise has on the 100-meter sprint running speed of class X MA Darul Ulum Waru Sidoarjo. This research is quantitative research with experimental method. The research design used was One Group Pretest and Posttest Design, namely experiments carried out in one group without a comparison group. While the sample in this study found 20 students at MA Darul Ulum Waru Sidoarjo. Results Based on the research, it is known that the minimum pretest value is 15.28, the maximum is 21.09, while the posttest value is at least 15 and the maximum is 16.72, while the sig. (2-tailed) in the experimental group is 028, so the value of sig (2-tailed) < 0.05, it can be said that Ho is rejected and accepted, it can be said that there is an effect on running training using Parachute Running on sprint running speed 100 meters (Students of Class X MA Darul Ulum Waru Sidoarjo). From the results of this study, it is hoped that running exercises using Parachute Running can be a reference as a variation of sprint running exercises so that they are not monotonous.Keywords: parachute running, 100 meter sprint.

Endurance product for sprinters

Endurance in sprint running is determined by the runner's ability to maintain maximum high speed at a distance and resist its decline due to fatigue that occurs during running. At present, recommendations for the development of sprint endurance are mainly intended for athletes using various means and methods of sports training. The development of this quality in athletes with the use of nutritional improvement technology has mainly general recommendations. Thanks to the nitrate contained in beets, the body absorbs more oxygen and fatigue less during exercise, contributing to the aerobic process. The main task of our work was: to determine the indicators of endurance in sprint running (repeated running of 100 m segments 5-6 times with the determination of the average), and to substantiate the methodology for the development of this quality in athletes using the technology of taking probiotics. The experimental data made it possible to reveal the effectiveness of the applied methodology for the development of endurance in sprint running. Moreover, the greatest effect was achieved using the method of circular training, with the inclusion of the means of speed-strength training in combination with running, as well as repeated running of short and long segments (30-200 m), alternating in one lesson, with a gradual decrease in the rest intervals. The experimental group that took beet juice showed a higher endurance increase in an average of 0.5 seconds than the control group, which allows us to draw a conclusion about the importance of taking nitrate in beets and its positive effect on the endurance of sprinters.