THE RELATIONSHIPS BETWEEN ANTHROPOMOTORIC BODY DIMENSIONS AND THE FORCE - TIME STRUCTURE OF THE VERTICAL JUMP

INTRODUCTION: The take - off activities are quite various and many of their modifications are used in sport. The final result of the jump is influenced by a great variety of factors such as the quality of produced muscle strength timing of the jump, range of movement, arm activities etc. The basic determinants of many movement activities are the body dimensions (length and mass variables). This paper is focused on the questions concerning the relationship between the forcetime structure of the vertical jump (time, distance, velocity, force, final results) and the body dimensions. METHODS: The counter-movement vertical jump (CMJ) with an arm swing was registered on a KISTLER platform. The reaction force Fz (t) was analysed on an ON-LINE system using software developed in our lab. 23 variables describing the structure of CMJ from the point of view of time, distance, velocity of the centre of mass (CM), and produced force were computed in real time. Eleven values of body dimensions were measured for each subject (length variables of the lower limbs, body height, mass, width of knee, and ankle). The subjects of this research were two groups of students of physical education (men, n=54, age: 18 - 20 years, height: 178.40 ± 6.12cm, body mass: 79.00 ± 6.36 kg; women, n=47, height: 168.48 ± 6.20 cm, body mass: 59.77 ± 6.44 kg). Correlation and factor analysis (STATGRAPHICS package) were used for the statistical analysis. RESULTS: The factor analysis of eleven anthropometric values showed two groups of dependent variables (length parameters and body height - 1st factor, and body mass and width variables - 2nd factor). The three factor model of the CMJ structure selected three groups of dependent variables for both the men and women (1st - time and distance variables, 2nd - impulse momentum and variables of the final results of CMJ, 3rd - variables of the preparatory phase of the CMJ). The factor analysis of body dimension and CMJ variables has shown that the body dimensions are an independent group of variables and that they do not have a relationship to the CMJ structure. CONCLUSION: Factor analysis confirms the relative independence of the three groups of CMJ variables (time and distance, impulse momentum and final variables of the CMJ, the preparatory phase variables). The set of body dimension parameters does not have a relationship to the structure of CMJ. This finding was the same for both groups of men and women

Verification of reliability of measurement systems for swimming analysis

Sophisticated technologies and measuring devices are increasingly being used for the analysis of performance and swimming techniques. At BUT, the Tachograph II and Swimming Inertial Measure Unit (SwIMU) measuring systems were developed for swimming analysis. To evaluate the measured data, the SwimDataViewer software was developed for both measuring systems. To verify the reliability of the Tachograph, 34 race swimmers were measured (15 F, 19 M), and 28 race swimmers (16 M, 12 F) were measured with SwIMU. All swimmers swam a 6x25m front crawl. Pullout and the first three and last two strokes of the arms were not included in the data evaluation. The intraclass correlation coefficient (ICC) was used to verify the reliability of the monitored parameters. The values of measured parameters in the front crawl for Tachograph (SwIMU) were ICC = 0.992 (0.991) for the average value of speed, ICC = 0.958 (0.960) for efficiency, ICC = 0.971 (0.988) for the frequency of the arms, and finally, ICC = 0.978 (0.992) for the frequency of the legs. The ICC coefficient for all monitored parameters in both devices showed a high degree of reliability. From this perspective, both devices are suitable for use in coaching and research practice

Development of an analysis of swimming techniques using instrumentation and the development of a new measurement method at Brno University of Technology

This article provides an overview of the development of measuring methods and instrumentation for the analysis of swimming techniques around the world, and describes in more detail the Tachograph method used in BUT (Brno University of Technology), including information about the currently developed method for measuring the swimmers using accelerometers. Our aim is to present a comprehensive view of the issue and describe the direction of the current development of measurement techniques used in swimming. The article further describes in detail the physical nature of the measurement methods and discusses their pros and cons. In addition to conventional methods (speedometer, accelerometer), we also mention unconventional methods (CFD method, 3D motion analysis etc.). The main contribution of the paper is in highlighting new directions and methods of measurement in swimming, including a specific approach for the evaluation of swimming techniques at the Brno University of Technology (BUT), where the scientific team at the Center of Sports Activities (CESA) has for several years developed and refined a tachograph measuring method with synchronous underwater video recording of swimmers. This method was used with swimmers from the Czech national swimming team and from Czech sports secondary schools as part of ongoing research and efforts towards more accurate measurements. Finally, the article describes current developments in measuring methods done at BUT using accelerometers

A LONGITUDINAL STUDY OF INTRA-INDIVIDUAL VARIABILITY IN THE EXECUTION OF THE IN-RUN POSITION IN SKI JUMPING

INTRODUCTION: The change of flight in ski jumping (V-style) has influenced a change in the take-off process. When considering this fact, it is necessary to determine whether the same applies to the in-run position – one of the basic phases of ski jumping. The ski jumper must master three basic tasks of the in-run position: maintenance of equilibrium, acquisition of maximum approach velocity and preparation for take-off. The main goal of this paper was to determine whether a set of various models of the in-run position exists for selected competitors. METHODS: Data for this study were collected from the Intersport tournee Innsbruck between 1992 and 1998 at a distance of 18 m prior to the edge of the jumping hill. A 2D kinematic analysis was used to evaluate the in-run position of the ski jumpers (500 analyses). The in-run position was evaluated using eight angle parameters. Jumpers were chosen from among the competitors who jumped at least four times in this event. Assessments of inter-individual and intraindividual variability were made. For analysis of the results, a computer statistical package ‘Statgraphics’ (one-way analysis of variance, Kruskal-Wallis one-way analysis by ranks, cluster analysis) was used. RESULTS: A large range for the analyzed angles existed for the group of selected competitors. The changes occurring among the selected segments of the body varied with each individual sportsman. The athletes under study could be divided into several qualitative groups: high stability of the lower extremities position (subjects 1 and 2), high stability of the upper extremities position (subject 3), high stability of the lower extremities with regard to the trunk position (subjects 4 and 5), in-run position with low stability (subject 6), etc. The position of the center of gravity for subjects 1, 4, 7, 8 and 9 was often stable even with high variability of the other parameters. The data supported the concept that the influence of anthropometric and physiological characteristics is very important. CONCLUSIONS: Changes in the in-run position were found in all ski jumpers in the period between 1992 and 1998. Statistically significant differences (interindividual variability) existed among years of measurement. Within the group of selected ski jumpers the execution of the in-run position varied for both body position and the position of the segments of the body. There existed an individual solution of this movement situation for most ski jumpers – it can be called an individualized model of the in-run position

THE INFLUENCE OF FOOT ALIGNMENT ON KINEMATIC PARAMETERS OF GAIT IN BALLET DANCERS

The aim of this study was to assess the relationship between kinematic parameters and foot rotation relating to gait direction. Thirty-two professional ballet dancers (15 males, 17 females; age 26.8±5.6 years) participated in this research. Each participant performed five trials of gait at self-selected walking speed. Kinematic data was obtained using the optoelectronic system Vicon MX. Foot axis angle (°) was obtained by Footscan (RSscan International). Significant differences (p < 0.05) between the kinematic variables and foot axis angle were observed at knee flexion in the stance phase and ROM (range of motion) and maximum pelvic rotation in female as well as knee ROM in the frontal plane, and maximum pelvic obliquity and rotation in men. Significant differences between two groups of dancers with foot axis angle under and above 15 degrees were found for the knee and pelvic kinematic variables. This altered movement can lead to increased stress load on the joints of the lower limbs and predispose to injuries or early degenerative changes in the musculoskeletal system. Avoiding excessive foot external rotation during gait may reduce load on the musculoskeletal system and may prevent injuries

BIONIC KNEES ALLOW OF SYMMETRICAL TEMPORAL-SPATIAL PARAMETERS OF GAIT COMPARED TO MECHANICALLY PASSIVE KNEE DESIGNS

The purpose of this study was to compare the basic temporal-spatial parameters of gait and gait symmetry in transfemoral amputees with a bionic knee joint with those in patients using a mechanically passive joint in relation to non-pathological gait. Seven subjects with a transfemoral amputation participated in this study. The amputee subjects performed fifteen attempts to walk across two Kistler force plates embedded in the floor. Objective gait measurements were acquired with a computerized video motion analysis system utilizing seven infrared cameras (Qualisys). Gait with a bionic knee joint showed greater symmetry than gait with a mechanically passive joint. When using a bionic knee joint, the stance and swing times approximated those in people without pathology

KINEMATIC ANALYSIS OF 100M HURDLE RACE IN FIRE SPORT

Fire sport is a discipline based on maximal movement velocity and optimal muscle-nerve co-ordination during the implementation of supporting movement activity. One of the most attractive disciplines is the 100m running event with various hurdles. The conclusive moment for passing a beam-hurdle is the way of starting towards the board. For analysis of this activity we used four video cameras and photocells to measure time parameters. According to efficiency we divided the monitored file (n=22, average age 24.37 years) into three groups. There is a trend, in order to maintain the velocity in the group of the best runners during the start, towards getting over the hurdle by executing the take off from the board is managed from a more forward position. In subjects with lowest efficiency there is a lowering of the ankle position during the runner’s contact with a rising board manifested via the braking rate

COMPARISON OF KINEMATIC PARAMETERS OF GAIT IN TRANSFEMORAL AMPUTEES WITH BIONIC AND HYDRAULIC KNEE – CASE STUDY

The development of new technologies has led to further improvements in prosthetic knee joints. The aim of this study was to compare kinematics in knee and hip joints during the gait of transfemoral amputees and to determine the effect of the type of knee joint used (bionic, hydraulic) on their symmetry. One female with transfemoral amputation participated in the study. Symmetry of lower limb movement in the hip joint is better for all monitored parameters for bionic knee joints. Flexion at heel contact and maximum flexion in the swing phase in the knee joint are more symmetrical at hydraulic knee joints; for all other parameters the bionic knee joints achieves better symmetry. Kinematics parameters in bionic knee amputees approximate to the parameters of gait in people without pathology

Hallux valgus surgery affects kinematic parameters during gait

Background The aim of our study was to compare spatiotemporal parameters and lower limb and pelvis kinematics during the walking in patients with hallux valgus before and after surgery and in relation to a control group. Methods Seventeen females with hallux valgus, who underwent first metatarsal osteotomy, constituted our experimental group. The control group consisted of thirteen females. Kinematic data during walking were obtained using the Vicon MX system. Findings Our results showed that hallux valgus before surgery affects spatiotemporal parameters and lower limb and pelvis kinematics during walking. Hallux valgus surgery further increased the differences that were present before surgery. Specifically after hallux valgus surgery, the walking speed decreased even more (p = 0.09, η2 = 0.19) while step time increased (p = 0.002, η2 = 0.44) on both legs. The maximum ankle plantar flexion of the operated leg during toe-off decreased to a greater extend (p = 0.03, η2 = 0.26). The asymmetry in the hip and the pelvis movements in the frontal plane (present preoperatively) persisted after surgery. Interpretation Hallux valgus is not an isolated problem of the first ray, which could be just surgically addressed by correcting the foot\u27s alignment. It is a long-term progressive malfunction of the foot affecting the entire kinematic chain of the lower extremity

Variability of spatial temporal gait parameters and center of pressure displacements during gait in elderly fallers and nonfallers: A 6-month prospective study

Considering that most of the falls in elderly population arise during walking, tests derived from walking performance would be desirable for comprehensive fall risk assessment. The analysis of spatial temporal parameters and the center of pressure displacement, which represents the interaction between the human body and the ground, would be beneficial. The aim of this study was to compare spatial temporal gait parameters and their variability and the variability of the center of pressure displacement between elderly fallers and nonfallers during gait at self-selected, defined and fast speeds. A prospective study design was used. At the baseline, measurements of ground reaction force during gait at self-selected, defined and fast walking speeds by two force plates were performed. In addition, the Tinetti balance assessment tool, the Falls Efficacy Scale-International and the Activities-Specific Balance Confidence Scale were used. Mean and coefficient of variation of spatial temporal gait parameters and standard deviations of center of pressure displacement during loading response, midstance, terminal stance and preswing phases were calculated. Comparison of the fallers and nonfallers exhibited no significant difference in clinical tool, scales or spatial temporal parameters. Compared to nonfallers’ increased variability of walking speed at self-selected and defined speed, step width at fast walking speed and center of pressure displacement during preswing phase in medial-lateral directions at defined walking speed was found in fallers. However, application of the Holm-Bonferroni procedure for multiple comparisons exhibited no significant effect of group in any of the gait parameters. In general, our study did not observe an effect of group (fallers vs. nonfallers) on variability of spatial temporal parameters and center of pressure movement during gait. However, walking speed, step width as well as standard deviation of COP displacement in the medial-lateral direction during preswing exhibited a certain potential for distinguishing between elderly fallers and nonfallers.Web of Science122art. no. e017199