Football is an intermittent sport with a great number of short and explosive actions. These characteristics of the game require a good level of anaerobic power. The main field tests used as indicators of the development of the anaerobic energy system were the jumps in the vertical plane. The same tests also measured the strength of the lower limbs. We presume that the explosive power of the lower limbs characterizes the development of the alactic anaerobic energy system and strength capacity at the same time. In that case the explosive power of the lower limbs was an important component of the conditioning and strength training of football players. There was a great variety of methods and devices which registered vertical jump height. From this point of view, we wanted to add our study to the research work in the specialized literature. The purpose of this study was to analyze the differences of the jump height measured via two devices. We used the following methods of research: accelerometry, chronometry and statistical analysis. We studied the vertical jump height of 32 football players of the Youth Academy of PFC “Levski”– Sofia at the age of 13,4. In the research the participants performed three jump tests (squat jump [SJ], counter movement jump [CMJ] and counter movement jump with arm swing [CMJA]) as the jump height was measured via accelerometer and Infrared platform. The results from these two devices were compared via Bland Altman plot and calculation of Intraclass correlation coefficients [ICC]. The results of ICC between the two devices showed very strong correlation of the results for the three tests (SJ (R= .91), CMJ (R= .92) and CMJA (R= .87)). The results of the ANOVA showed statistical difference between the measured jump heights (p< .05 for all test, systematic bias was equal to: SJ=15.6; CMJ=15.2; CMJA= 19.5 and effect size (η2 ) was large SJ= .65; CMJ= .69; CMJA= .65) for the three different types of jump. Conclusions:1) Both of the devices showed good consistency of the collected results; 2) The data collected from the two devices showed significant difference of the jump heights.

The focus of the research is the motion characteristics of the teams which participated in the World cup 2018 in Russia. For the purpose of the research we collected the data from all the matches in the knock out phase of the tournament. We divided the results for every position during the halves and calculated the total distance covered. This way we could get an idea of the intensity and the profile of elite soccer players. In the analyses we included 273 players that played in the knock out phase. As a result of the research, we found that the goalkeeper had total distance covered of 4061,59 metеrs; defenders had a 9352 metеrs; midfielders had a 10708 metеrs and strikers had a 9731 metеrs. It is interesting that the total distance covered during the second half is greater than in the first one. Conclusion of the research is that the total distance covered is different for all of the researched positions which is a predisposition for disclosing the motor profile of the players. From the study of motor activity in football at world championships we can draw the following conclusions: 1) The results are comfirmation that even at a World Cup the performance characteristics are greatly influenced by position of play; 2) The higher total distance covered during the second half suggests extremely high aerobic capabilities of elite football players

Focus of this research is the relationship between the motor abilities. The interest in this topic is dictated from the fact that there isn’t enough information about it in elite female football. For the purpose of the research we made tests to define the level of development of the motor abilities of 68 elite female football players. We also made a descriptive statistics and correlation analysis and we received the following results: descriptive statistics shows that the researched indicators are highly homogeneous (in range of V% =2,67 to 5,05); the correlation between accelerative abilities and maximal sprinting abilities is moderate and positive (r= 0,634); the correlation between power abilities with explosive character and other researched abilities is moderate and negative (r= -0,430, r= -0,494, r= -0,455); the speed endurance abilities have moderate to strong and positive correlation with the accelerative and maximal sprinting abilities (r= 0,600, r= 0,809). Conclusions: 1) Improving the power abilities with explosive character creates beneficial conditions in development of the other motor abilities; 2) Improving of the speed abilities is a major component of the conditioning in female soccer; 3) The most important factor for improving the speed endurance is creating a “speed reserve”.

Objectives. The present study aimed to quantify changes in spinal kinematics during Nordic walking compared to regular walking (RW) for 60 s on a training path among physically fit young males (n = 20, aged 19–22 years). Methods. Two walking speeds were analyzed: 3 km/h and 5 km/h. The experimental setup was designed to assess spinal angular rotations using five kinematic parameters: upper spine, lower spine, thoracic region, lumbar region, and pelvis. Results. The data were acquired from 9 compact inertial sensors and the following motion analysis is carried out using 3D MioMotion IMU sensor’s analysis system. The differences in the obtained cyclic biomechanical parameters were detected using functional data analysis (FDA) statistical tests. Conclusions. The key finding of the study is that Nordic walking significantly alters the angular kinematic pattern of spinal movement as it revealed significant differences in all five measured parameters when compared to normal walking. Notably, the most pronounced changes were observed in the upper spine and pelvis motion. Additionally, Nordic walking increased stance phase duration and velocity: (i) significantly increased the duration of the stance phase in all three planes of motion; (ii) significantly increased the velocity during the stance phase across all three planes. These reported findings highlight the biomechanical, preventive, therapeutic, and rehabilitative potential of Nordic walking.

The half-marathon originated from the marathon as its length is half a marathon or 21.0975 km. This discipline is one of the newest in the World Athletics program, as the first major championship of this distance was in 1992 in England. Even earlier, the running community created distance as an alternative to marathon running in the 50s of the 20th century. Despite its relatively long history, there is little data on the biomechanical indicators of the competitors participating in the discipline. Hence, the present study aims to determine the leading indicators characterizing running speed in the half-marathon discipline and the influence of fatigue on these indicators. To achieve the study's goal, we implemented the following tasks: 1) Measurement of the main characteristics of the running speed in 3 sections of the racing distance, 2) Determination of the variability of these indicators. To solve the study tasks, we used video analysis and statistical methods. After the analyses, we find differences in the length and frequency of the strides of competitors with different qualifications. Highly trained athletes (HT) had a more even pace (1:00-3:04 min per section) than moderately trained athletes (MT) (3:25-5:19 min per section). HT athletes had greater stride length (1.61-1.70 m) than MT athletes (1.50-1.54 m) in all sections. MT athletes rely more on stride frequency than on stride length to increase their movement speed. HT athletes are opposite MT athletes. Conclusions: 1) The results obtained show the possibilities for using drones for the needs of kinematic analysis in running 2) From the differences in running speed, we can determine that VT athletes manage to distribute their efforts more evenly over the competition distance than the MT athlete; 3) The decrease in speed at the end of the competition distance in VT athletes is mainly due to the shorter stride length.

Lower limb strength imbalance and inter-limb asymmetry are relevant neuromuscular screening markers in women’s football, yet data from national-champion squads in Eastern Europe remain limited. The aim of this study was to characterise lower limb isometric knee strength, hamstring-to-quadriceps (H:Q) ratios, and bilateral and unilateral squat jump (SJ) and countermovement jump (CMJ) performance, and to describe their distribution by playing position, in elite Bulgarian female football players. Nineteen players from FC NSA Sofia Women (Bulgarian Women’s Football Champions, 2024/25; age 20.9 ± 4.3 years; height 168.4 ± 4.7 cm; body mass 60.5 ± 8.0 kg; body mass index 21.3 ± 2.7 kg·m ⁻² ) were assessed on a single testing day using a handheld dynamometer (Kineo Intelligent Load) and an optical jump system (Optojump Next). Mean H:Q ratios were 0.58 ± 0.10 (left, 95% CI [0.52, 0.64]) and 0.55 ± 0.07 (right, 95% CI [0.51, 0.60]); the right-limb mean was statistically below the 0.60 reference threshold (t(13) = −2.40, p = 0.032, d = −0.64). Thirteen of fourteen assessed players (92.9%, 95% CI [68.5–98.7%]) presented at least one limb with an H:Q ratio below 0.60. Mean bilateral SJ and CMJ were both 29.2 cm, producing a near-zero elasticity index (0.99 ± 10.6%). Unilateral asymmetry exceeding 10% was observed in 52.9% of players for SJ (95% CI [31.0–73.8%]) and 35.3% for CMJ (95% CI [17.3–58.7%]). Positional profiles are reported descriptively only, given the small subgroup sizes. The findings support routine neuromuscular screening of lower limb strength balance and unilateral jump performance in elite women’s football, and indicate that conditioning programmes should address both hamstring and quadriceps capacity rather than hamstring strength in isolation.