ISBS (International Society of Biomechanics in Sports): Conference Proceedings Archive
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A CALIBRATION PROCEDURE FOR MIMU SENSORS ALLOWING FOR THE CALCULATION OF ELBOW ANGLES
Full text linkNon-optical wearable sensors such as magnetic and inertial measurement units (MIMUs) are gaining popularity in sport and clinical settings owing to their ease of application, relative affordability and potential for improved ecological validity. We propose a method for the standardised reference calibration of a simple two-sensor MIMU system for the estimation of anatomically meaningful elbow kinematics. The participant poses with the elbow at 90° flexion and neutral (0°) pronation, allowing for the relative orientation of the MIMU on the forearm to be determined with reference to the MIMU located on the arm. Comparisons were with traditional kinematic marker method results. Root mean squared errors of less than 1° in flex/ext and < 2° (pro/sup) found in simple movements. Results with simple movements provide rationale to expand research to complex movements
KINEMATICS ANALYSIS ON HANDSPRING SIDEWAYS STRETCHED SIDEWARD SOMERSAULT WITH 1 3/4 TURNS IN HORSE-VAULTING OF ZEPENG LUO
Full text linkBy using the 3D video analysis method, we have tested on the handspring sideways stretched side-ward somersault with 1 3/4 turns in Horse-vaulting (also known as Kasamatsu 360°) of Chinese elite athletes Zepeng Luo at the game site; obtain the relevant kinematics’ parameters through analysis on the complete movement. The results show that: Zepeng Luo completed this action with high quality and advanced technology, but at the first flight, his legs were not fully close together
ANALYSIS OF THE SPRINTS FEATURES DURING FUTSAL MATCHES
Full text linkThe purpose of this study was to analyse the repeated-sprint sequences (RSS) and to characterise the sprints performed during futsal matches. Automatic tracking system was used to obtain the player’s trajectories (n=97) during five official matches. The sprints were analysed during the both halves and RSS were categorised according to the number of sprints and the time between them. The results showed a decrease in the number of sprints per minute in the second half. However, the duration of the sprints was greater in the second half. For the RSS analysis, the results showed that the most frequent RSS consisted of two sprints interspersed with a maximum of 15 s of recovery. The study characterised the features of sprinting of futsal players, which can help coaches to plan physical training and assessments according to the sport requirements
EFFECTS OF FOOT PLACEMENT ON RESULTANT JOINT MOMENTS OF LOWER EXTREMITY JOINTS DURING SQUAT
Full text linkThe purpose of this study was to investigate the effects of foot placement (stance width and foot angle) on normalized sagittal- and frontal-plane resultant joint moments (NRJM) of the lower extremity joints during the squat. Forty-two participants were recruited: male (n = 21) and female (n = 21). Three-dimensional motion analysis and inverse dynamics analysis were conducted. There was a significant interaction between the stance width and foot angle on the NRJM in the sagittal plane, whereas there were significant main effects of the stance width, foot angle, and gender on the NRJM in the frontal plane
BIOMECHANICAL ANALYSIS OF BADMINTON DIFFERENT FORWARD STEPS
Full text linkThe purpose of this study was to compare the biomechanical variables between 2-step and 3-step forward steps in badminton. Eight collegiate elite male badminton players participated in this study. Eight Vicon T-20 cameras (300 Hz) were used to record the 3D kinematics data and a Kistler force plate (1500 Hz) was used to collect the GRF data of the last steps. A Wilcoxon matched-pairs signed-rank nonparametric statistical test was conducted to compare the differences between two kinds of forward step movements. The results showed that the movement time for 3-step movement was significantly faster than 2-step. We recommend that the badminton players should practice 3-step forward footwork technique. The additional strength and power training for lower limbs should be carried out for the footwork training
EFFECT OF THE LOCATION OF THE FOOT IMPACT POINT ON BALL VELOCITY IN A SOCCER PENALTY KICK
Full text linkThe aim of this study was to identify the impact point on the foot that maximizes ball velocity in a soccer instep penalty kick. One male player performed 23 maximum-effort penalty kicks using a wide range of impact points along the length of his foot. The kicks were recorded by a video camera at 100 Hz and a biomechanical analysis was conducted to obtain measures of impact point, ball projection velocity, and kinematics of the kicking leg. We found that ball velocity was insensitive to the location of the impact point (at least for positions between the ankle joint and the base of the toes). This result suggests that players should consider other factors (such as shot accuracy, shot reliability, and foot comfort) when selecting the impact point
INFLUENCE OF PLAYING LEVEL ON THE KINEMATICS AND KINETICS OF THE RUGBY SCRUM
Full text linkThe aim of this study was to examine the force production, lower body kinematics and kinetics of front row rugby union forwards during the engagement phase of a simulated rugby union scrum. Twenty-eight male front row players were divided into three groups; professional, senior and junior amateur players. Players performed five trials based on the International Rugby Board scrum engagement sequence. Three dimensional motion analysis and force plate data were used to determine joint angles and reaction forces both on the scrum machine and on the ground. Professional front row forwards generated significantly greater force during the engagement phase compared to both senior and junior amateur players. Professional players had a significantly greater knee abduction angle and generated larger peak hip joint power compared to both junior and senior players
INFLUENCE OF TRADITIONAL AND NON-TRADITIONAL ENTRIES ON FIGURE SKATING JUMPS
Full text linkThe choice of performing jumps from traditional entries or nontraditional entries are left to the discretion of the skater. The purpose of this study was to examine the influence of non-traditional entries on the kinematics of two figure skating jumps using a simple quantitative tool available to coaches. It was hypotheisized that non-tradional entries would alter jump kinematics. Ten skilled figure skaters were videotaped while performing toe loops or salchows with both traditional and non-tradional entires. Kinematic variables were determined with Dartfish. Results indicated that non-traditional entries had significantly more jump height and ankle plantar flexion at landing in the toe loop, and signifcantly more horizontal displacment in the salchow. Coaches may wish to examine these subtlies to determine a skater’s readiness to practice non-traditional entries
BIOMECHANICAL ANALYSIS OF SAVING MOTION FOR SOCCER GOALKEEPERS FOCUSED ON THE FUNCTION OF LOWER EXTREMITIES
Full text linkThe purpose of this study was to clarify the function of the lower extremities during the saving motion of a goal keeper (GK). Eleven male university GKs dived toward a ball thrown 3.5 m ahead. Three-dimensional (3D) coordinates and ground reaction forces were obtained with a 3D motion capture system (250 Hz) and 2 force platforms (1000 Hz). The novel findings in this study are summarized as follows: (1) hip extension of the contralateral side leg to the ball is an important motion in the Pre phase and (2) exertion of extension torque at the hip in the early Transition phase has an important role for controlling backward leaning of the thigh during the saving motion
ACUTE EFFECTS OF TRAINING ON HURDLE CONFIGURATION DURING SPRINT HURDLE MOTION
Full text linkHere we assessed the acute effects of training in hurdle configuration on sprint hurdle motion in five male hurdlers. We compared the hurdlers’ motion between the pre- and post-training conditions for three different types of training programs. Our results showed that a short-interval training program was effective in reducing the duration of all four step, particularly that of the 2nd step. On the other hand, a long-interval training program particularly influenced the characteristics of the 3rd step without improving the overall four steps. Thus, a long-approach training was effective in adjusting the ground reaction force in the support phase of the 4th step, necessary to appropriately clear the hurdle