Some Biomechanical Variables of Hurdle Clearance Steps (1-4-8) and Their Relationship to the 100m Hurdles Performance for Advanced Female Athletes

Clinical outcomes and frontal plane two-dimensional biomechanics during the 30-second single leg stance test in patients before and after hip abductor tendon reconstructive surgery

Osteoporotic fracture has been found associated with many clinical risk factors, and the associations have been explored dominantly by evidence-based and case-control approaches. The major challenges emerging from the studies are the large number of the risk factors, the difficulty in quantification, the incomplete list, and the interdependence of the risk factors. A biomechanical sorting of the risk factors may shed lights on resolving the above issues. Based on the definition of load-strength ratio (LSR), we first identified the four biomechanical variables determining fracture risk, i.e., the risk of fall, impact force, bone quality, and bone geometry. Then, we explored the links between the FRAX clinical risk factors and the biomechanical variables by looking for evidences in the literature. To accurately assess fracture risk, none of the four biomechanical variables can be ignored and their values must be subject-specific. A clinical risk factor contributes to osteoporotic fracture by affecting one or more of the biomechanical variables. A biomechanical variable represents the integral effect from all the clinical risk factors linked to the variable. The clinical risk factors in FRAX mostly stand for bone quality. The other three biomechanical variables are not adequately represented by the clinical risk factors. From the biomechanical viewpoint, most clinical risk factors are interdependent to each other as they affect the same biomechanical variable(s). As biomechanical variables must be expressed in numbers before their use in calculating LSR, the numerical value of a biomechanical variable can be used as a gauge of the linked clinical risk factors to measure their integral effect on fracture risk, which may be more efficient than to study each individual risk factor.

It is already clear the importance of resistance training with elastic bands to improve the level of performance compared to more traditional drills. So the present study aimed to identify the effect of functional resistance drills with elastic bands on some of physical and biomechanical variables and kicking accuracy in soccer junior. Experimental method was used; (pre-test & post-test), with a single experimental group, from fifteen soccer Junior (aged 17.54 ±0.7 years, body mass: 67.84 kg, height: 171.53cm) constituted one experimental group. and (5) junior for pilot study (n=15), functional drills and the pretest–posttest are done during specific prep phase of training with duration 10-weeks training program for (3 training units per week for 2hrs), Repetition (8-12), and (3-5) sets. after the functional resistance drills finish, biomechanical analysis was performed using motion analysis Program (win analyze) computer-assisted. It was a post-test to compared the pre-test by using statistical procedures: (Mean - standard deviation – Median - Coefficient of Skewness – T-Test ), and discussion it was possible to conclude the Functional resistance training using elastic bands has improved values of the biomechanical variables under study in post-test, it is improved performance of kicking in front of the front foot on goal, as well as led to kinetic bonding between the leg joints (Hip- Knee- Ankle) in backswing and impact phases while kicking performance. Study shows that there are statistically significant differences between the mean (pre-test and post-test) measurements of the study sample, with pre-test at the level (0.05) in all physical variables and accuracy and kick timing, this is confirmed by the results this study, where Static balance (3.632 s) Muscle strength for back extensors mean was (70 Kgf), Muscle strength for legs extensors mean was (131 Kgf), Quadrant jump test mean was (3.166 s), High jump from stability mean was (76.33 cm) Illinois agility mean was (11.530 s), Accuracy kick mean was (4.833 Deg.) and Kick timing mean was (0.278 s).

Biomechanical variables related to walking performance 6-months following post-stroke rehabilitation

The triple jump is consider one of the track and field competitions that is distinguished by difficult technique which include the approach run , hop, step, jump and the landing phases , and considering of what these phases need of high physical and skill training , and to recognize to the features of these phases and standing-up of the variables that should attention with to improving and developing these phases, the study problem was specified in study the bio-kinematical variables that effect in triple jump phases performance specially the last three steps variables that effect largely on the take-off and with relation to the approach run velocity and fulcrum angle (the frontal body fulcrum angle) and other body angles, also the take-off phase with it’s two parts (collision absorption- absorption push) in addition to fulcrum and take-off angles for the phase itself. The research aims to identify: 1 – Values of achievement of the research sample 2 – values of some bio-kinematical variables for the last three steps and take-off phases in the triple jump for a sample research. 3 - The relationship between some bio-kinematical variables for the last three steps and take-off phases in the triple jump and achievement. The researchers had hypothesized that there is a significant correlation between some bio-kinematical variables for the last three steps and take-off phases in the triple jump with achievement. The researchers used the descriptive method with the analysis and correlations style for its convenience to the research nature. The research sample consisted of (6) jumpers representing advanced players participating in the Iraqi tournament of triple jump . The researchers had used measurement, test and technical scientific observation as a tools for data collection, technical Scientific observation was carried out by using four video cameras , three of them were placed on left side of player to obtain the values of bio-kinematical variables of (hope , step, jump)phases and the fourth was placed in the face of the player to extract the deviations paths that player passes by side, A yard stick of one meter was used and filmed in both positions (horizontal and vertical) to calculate alteration coefficient from the image to reality in order to obtain bio-kinematical variables. each player has performed (6) attempts and the best attempt at achievement analyzed using computer softwares for kinetic analysis. Data were statistically handled treated through applying (spss) program to obtain (the arithmetic mean, standard deviation , the simple correlation)as well as equations correlated with biomechanics variables.

PurposeAnterior cruciate ligament (ACL) injuries have consistently been linked to specific kinetic and kinematic patterns, including elevated vertical ground reaction forces, increased knee abduction angle and moment (dynamic valgus), reduced knee flexion during landing and excessive hip adduction/internal rotation. However, the relationship between motor competence as a factor affecting athletes' performance and kinetic and kinematic variables has not yet been investigated.MethodsA total of 112 elite athletes (66 males and 46 females; mean age = 19.4 ± 1.1 years) from basketball, volleyball and handball were assessed. Motor competence was evaluated using the short form of the Bruininks–Oseretsky Test of Motor Proficiency. Biomechanical data were collected during a single‐leg drop landing task using a three‐dimensional motion analysis system (Vicon) and a force plate. Pearson correlation coefficients and multiple linear regression (Enter method) were used to analyse relationships between motor competence and kinetic/kinematic variables.ResultsAll biomechanical variables showed significant correlations with motor competence (p < 0.001). Notably, knee flexion angle (r = 0.613) and knee abduction angle (r = −0.576) demonstrated strong associations. Regression analysis identified several biomechanical variables that were statistically associated with motor competence, explaining 69.6% of its variance.ConclusionMotor competence was related to several kinetic and kinematic variables previously linked to ACL injury risk. However, due to the cross‐sectional design, these associations should not be interpreted as causal, and further longitudinal or interventional studies are warranted.Level of EvidenceLevel IV, cross‐sectional study.

Jumping ability is a fundamental variable in many sports, as its execution requires an integration of muscular strength Q1 and certain biomechanical variables. This is particularly evident in gymnastics jumping events and jump shots in ball games, both of which rely on a high level of vertical resistance. Vertical resistance serves as an indicator of an athlete’s ability to overcome their body weight while counteracting gravitational force to achieve optimal performance. As such, it is considered one of the key factors in movements that demand explosive power and speed. The researchers believe that despite the significant relationship between vertical resistance, speed-strength of the arms and legs, and certain biomechanical variables in determining athletic performance across various sports activities, the limited number of studies addressing this relationship makes it difficult to provide precise scientific data on its importance. This is particularly relevant to female students in the College of Physical Education and Sport Sciences, who often struggle with performing activities that require jumping or shooting while airborne with proper technical execution. This underscores the need for a more comprehensive and in-depth study of the factors in uencing such performance. This research aims to bridge the existing knowledge gap by analyzing these relationships among a sample of female students from the College of Physical Education and Sport Sciences for Women. The study seeks to highlight the key factors affecting student performance. Accordingly, the research problem is framed in the following question: What is the relationship between vertical resistance, physical abilities, biomechanical variables, and the execution of sports activities (high jump, jump shooting, and vaulting) among third-year female students? The study aimed to examine the relationship between vertical resistance, speed-strength of the arms and legs, and certain biomechanical variables during the take-off phase, as well as their impact on the execution of vaulting, jump shooting accuracy in handball, and jump shooting accuracy in basketball. The researchers hypothesized that there is no statistically significant relationship between vertical resistance and speed-strength, nor between vertical resistance and certain biomechanical variables during the take-off phase. Additionally, they posited that no statistically significant relationship exists between vertical resistance and the performance or accuracy of the examined activities. Adescriptive research methodology was employed, with the study sample consisting of eight third-year female students from the College of Physical Education and Sport Sciences for Women, selected through purposive sampling.

Studies have demonstrated the need for the use of parameters that diminish the effect of body mass, for intra and inter group comparison, in individuals with different masses in order to provide a different analysis on the behaviour of the relation between running economy (RE) and biomechanical variables (BVs). The allometric scale is represented by a regression equation that indicates the behaviour of a physiological variable in relation to the variable mass (RE=a.xb), where x is body mass in (kg) and the dimensionless coefficient a is characteristic of the species analysed, and the dimensionless exponent b determines the percentage of mass to be associated with the physiological variable. The influence of the allometric scale (b=-1; -0.75; -0.73; -0.67) on the relationship between RE and BVs - stride length (SL), relative stride length (RSL), stride rate (SR), stride time (ST), support time (SUPT) and balance time (BALT) - at 12 km.h -1 , was analysed in nine elite runners. Factorial analysis and Pearson's Correlation Coefficient test (r) with P<0.05 were used. A decrease in the explanation power of the RE was observed, with the use of the allometric exponent, due to the BVs, as well as a reduction of the correlation coefficients between SL versus RE, ST versus RE and SR versus RE. The BALT presented a higher correlation where b=-0.75. The RSL and SUPT presented non-significant correlations. The variables SL, ST, SR and BALT were the most effective predictors of the RE, Where: b=-1, the allometric scale was most efficient to predict the running performance. (Biol.Sport 26:263-273, 2009)

The development of technical performance level for players of 400 m barriers running came through selecting modern teaching devices which assist in learning process of this skill . Therefore, the researcher decided to use the technical devices for learning and monitoring the performance and obtaining information and later using such information to correct the performance in all stages of activity . The activity of 400 m barriers running is regarded as one of the activities which has been witnessing recorded due to the use of the suitable and special exercises commensurate with the activity of 400 m barriers running . The research significance lies in revealing some biomechanical variables affecting in the nature of the performance of the activity of 400m barriers running to prepare special exercises ,according to some biomechanical indicators, effective training methods for coaches in order to develop the achievement of young players . The research problem lies in the physical level of runner and their abilities to play an important and basic role in performing 400m barriers running which distinguish among runner as well as a number of biomechanical variables which happen at the effective moment of to move up and cross the barrier and the consequences which negatively affect the motor track for the skill which started at the moment of arise passing through the moment of crossing the barrier and ending at the moment of landing after the barrier and the consequences such as the technical performance and precise control of body parts at these moments. The research objective was to identify the values of the biomechanical variables as well as the number of specific exercises according to the biomechanical indicators of the research sample. The research sample consisted of 6 junior players . The researcher has concluded the flowing: 1.The special exercises in accordance with the biomechanical variables have effectiveness in developing achievement of 400m barrier race by juniors 2.The aiding devices and tools which were in accordance with performance and used within the prepared special exercises had positive effect in developing some biomechanical variables .

The goal of the research is to identify the following: 1-Evaluate some of the biomechanical variables of the wall barrier skill of stability and motion in volleyball. 2-Differences in some biomechanical variables between the barrier wall skill of stability and motion in volleyball. The researcher hypothesized that there are differences of statistical significance in the values ​​of some biomechanical variables between the barrier wall skill of stability and motion in volleyball. The researcher used the descriptive approach in the method of analysis and comparison to the relevance of the nature of the research. The researcher conducted the final field experiment on a sample of (5) advanced players representing the team of the University of Mosul volleyball، and were chosen in a deliberate way. The researcher used the technical scientific observation، the questionnaire، the measurement، the analysis and the test، as a means of collecting data to obtain the research variables under study. The researcher also used the following programs in the analysis: 1 - MAX TRAQ 2 - ACD See Statistical methods: arithmetic mean، standard deviation، T test of associated samples. The researcher reached the following: 1-There are significant differences in the variable velocity of the corner of the body from the maximum flexion until the moment left the ground between the barrier wall of stability and motion and in favor of the barrier wall of the resistance of the motion. 2-There are significant differences in the variable motor kinetic motion of Mtcj maximum of flexion until reaching the highest rise between the wall of the resistance of stability and motion and in favor of the wall of the resistance of the motion. 3-There are significant differences in the variables (total time، displacement and vertical speed of Mtkj، angular velocity of the knee joint، angular velocity of the trunk، vertical momentum، corner velocity of the hip joint in favor of the wall of the motion. The researcher recommended. 1- Emphasis on the main section of the motion, ie, the state of readiness and readiness and start to perform the wall of the correct form. 2 - Emphasis on the side step to prepare for the advancement because of the role of large in the player to get a vertical shift and thus get a vertical speed to enable it to reach the highest altitude.

The aim of the search is to: Codification of a skill test according to the electronic drip system for the front circular kick for Taekwondo players, as well as to identify the values of some biomechanical variables for the front circular kick for Taekwondo players and to identify the values of the two variables (strength and accuracy) of the front circular kick for Taekwondo players according to the electronic drip system, in addition to identifying the relationship between the values of Some biomechanical variables and the productive force for the performance of the front circular kick for taekwondo players according to the electronic drip system, as well as revealing the relationship between the values of some biomechanical variables and the accuracy of the front circular kick for taekwondo players according to the electronic drip system. The researchers hypothesized that there is a significant relationship between the values of some biomechanical variables and the producing force of the front circular kick of Taekwondo players according to the electronic drip system, and the existence of a significant relationship between the values of some biomechanical variables and the accuracy of the front circular kick of Taekwondo players according to the electronic drip system. The researchers used the descriptive approach using the two survey methods and the correlational relationships for its relevance and the nature of the study. The research community consisted of taekwondo players, the advanced category, which numbered (75) players representing the players of the teams (Baghdad, Nineveh, and Erbil). The research sample consisted of a sample of the two exploratory experiments, the number of its members (9) players were chosen from the research community, five of them from the Nineveh Governorate team, the tests for the front circular kick were applied, and four from the Erbil Governorate team to apply the biokinematic analysis tests. And the sample of the application of the tests consisting of (50) players representing the teams (Baghdad, Nineveh, and Erbil), and the stability sample consisting of (10) players, in addition to the analysis sample, they are (6) players who were chosen in a deliberate way who represent (3) from the Nineveh Governorate team and (3) From the Erbil governorate team. The researchers used measurement, testing, and technical scientific observation as means of data collection. The scientific observation was carried out using three video cameras at a speed of (100) images/sec. The researchers also used the electronic drip

Identifying atypical lower limb biomechanics may help prevent the occurrence or recurrence of running-related injuries. No reference values for spatiotemporal or kinetic variables in healthy recreational runners are available in the scientific literature to support clinical management. To (1) present speed- and sex-stratified reference values for spatiotemporal and kinetic variables in healthy adult recreational runners; (2) identify the determinants of these biomechanical variables; and (3) develop reference regression equations that can be used as a guide in a clinical context. Descriptive laboratory study. This study involved 860 healthy recreational runners (age, 19-65 years [38.5% women]) tested on an instrumented treadmill at their preferred running speed in randomly allocated, standardized running shoes with either hard or soft cushioning. Twelve common spatiotemporal and kinetic variables-including contact time, flight time, duty factor, vertical oscillation, step cadence, step length, vertical impact peak (VIP), time to VIP, vertical average loading rate, vertical stiffness, peak vertical ground-reaction force (GRF), and peak braking force-were derived from GRF recordings. Reference values for each biomechanical variable were calculated using descriptive statistics and stratified by sex and running speed category (≤7, 8, 9, 10, 11, 12, 13, 14, and ≥15 km/h). Correlations and multiple regression analyses were performed to identify potential determinants independently associated with each biomechanical variable and generate reference equations. The mean running speed was 10.5 ± 1.3 km/h and 9 ± 1.1 km/h in men and women, respectively. While all potential predictors were significantly correlated with many of the 12 biomechanical variables, only running speed showed high correlations (r > 0.7). The adjusted R2 of the multiple regression equations ranged from 0.19 to 0.88. This study provides reference values and equations that may guide clinicians and researchers in interpreting spatiotemporal and kinetic variables in recreational runners. The reference values can be used as targets for clinicians working with recreational runners in cases where there is a clinical suspicion of a causal relationship between atypical biomechanics and running-related injury.

The purpose of this study was to improve our understanding of the relative contributions of biomechanical, anthropometric, and psychological factors in explaining maximal bench press (BP) strength in a heterogeneous, resistance-trained sample. Eighteen college-aged participants reported to the laboratory for three visits. The first visit consisted of psychometric testing. The second visit assessed participants’ anthropometrics, additional psychometric outcomes, and bench press one repetition maximum (1RM). Participants performed isometric dynamometry testing for horizontal shoulder adduction and elbow extension at a predicted sticking point joint position. Multiple linear regression was used to examine the relationships between the biomechanical, anthropometric, and psychological variables and BP 1RM. Our primary multiple linear regression accounted for 43% of the variance in BP strength (F(3,14) = 5.34, p = 0.01; R2 = 0.53; adjusted R2 = 0.43). The sum of peak isometric net joint moments from the shoulder and elbow had the greatest standardized effect (0.59), followed by lean body mass (0.27) and self-efficacy (0.17). The variance in BP 1RM can be similarly captured (R2 = 0.48) by a single principal component containing anthropometric, biomechanics, and psychological variables. Pearson correlations with BP strength were generally greater among anthropometric and biomechanical variables as compared to psychological variables. These data suggest that BP strength among a heterogeneous, resistance-trained population is explained by multiple factors and is more strongly associated with physical than psychological variables.

Background. Success in sprinting events broadly depends on many factors. Among them, the reaction time at starting is one of the main factors that help sprinters get success by increasing their confidence and helping to avoid false starts. Study purpose. The purpose of the study was to find out the relationship between reaction time and performance time among women finalist sprinters in six Olympic Games since 2000. Materials and methods. Data were collected from 227 (n = 227) women finalist sprinters in the event of 100m (n= 47), 200m (46), 400m (43), 100m H (45), and 400m H (46) in 6 Olympic Games from 2000 to 2020, based on published official reports on worldathletics.org and olympedia.org websites. Data were considered from 227 samples from a total of 240 finalist women, where 13 were excluded because of a false start, being disqualified for doping, or failing to finish. Descriptive statistics, the Pearson correlation coefficient and simple regression analysis were used to determine the relationship between reaction time and performance time of the finalist women sprinters. The significance level was set at 0.05. Further Gaval’a 5-point scale was used to categorize the women sprinters based on their reaction times in five sprint events. Results. The results showed that there was a low positive correlation between reaction time and performance time among the sprinters in the 100m (r = 0.369, p&lt;0.05) and 100m H (r = 0.367, p&lt;0.05) events, whereas no relation was confirmed in 200m, 400m and 400m hurdles among women sprinters who participated in 2000-2020 Olympics. The 5-point scale revealed that 33.48% of sprinters belong to the average category, while 25.99% are in the unsatisfactory category, and only 1.32 % and 16.74% are in the excellent and very good categories, respectively. Conclusions. The current analysis concludes that there was a low positive relationship between reaction time and performance time of the finalist women sprinters only in sprint events of 100m and 100m hurdles during 2000 to 2020 Olympics, and the majority of the finalists belonged to the ‘Average’ category as per Gaval’a 5-point scale.

The aim of this study is to evaluate the influence of crown-to-implant (CI) ratio as well as other surgical, prosthetic and biomechanical variables on marginal bone loss (MBL) and on the survival rates of implant-supported prostheses in short implants (≤8.5 mm in length) placed in posterior areas of maxilla and mandible. This was a retrospective study based on clinical charts and follow-up recordings from a single private practice over a period of 10 years. Patients rehabilitated in the posterior region of the jaws by means of prostheses supported by implants of ≤8.5 mm length were included. Patients-related, surgery-related. and implant-related variables, as well as other prosthetic and biomechanical variables. were registered. The data were split into two groups according to the value of CI ratio (CI < 2 and CI ≥ 2). MBL was measured from radiographs using an image analysis software. Implant and prosthesis survival rates were recorded. One hundred twenty-eight short implants placed in 63 patients were evaluated. The mean follow-up period was 21.88 months (standard deviation (SD): 22.9, range 7-113 months). Eighty-six implants (67.2%) had a CI ratio of <2, whereas it was ≥2 in 42 implants (32.8%). The mean value of CI ratio was 1.82 (SD: 0.42; range 1.04-3.31). The average MBL after 1 year of follow-up was 0.35 (SD: 0.50), and it was 0.45 (SD: 0.46) mm for subsequent evaluations. Survival rates of implants and prosthesis were 100%. The presence of a cantilever had a negative influence on the first year MBL (p < .05). The CI ratio had not a significant influence on MBL in Biotechnology Institute (BTI; Vitoria, Spain) short implants humidified with PRGF-Endoret and placed in posterior areas. The only variable that showed a significant negative influence on first year postloading MBL was the use of cantilever for rehabilitations.