ISBS (International Society of Biomechanics in Sports): Conference Proceedings Archive
Not a member yet
5464 research outputs found
Sort by
EFFECT OF A BlOMECHANlCAL FACTOR ON ENERGY EXPENDITURE BY DISTANCE RUNNERS DURING REPEATED VERTICAL JUMPS
Full text linkThis study aimed to clarify a biomechanical factor that would affect energy expenditure during repeated vertical jumps. The subjects, nine male Japanese distance runners, jumped for 3-min periods on a force platform under four different conditions. Motion and electromyography (EMG) data were recorded with a high-speed camera and surface electrodes, respectively. The following results were obtained: 1) the integrated EMG of the rectus femoris and vastus lateralis was greater in the Low and Decline conditions than in the High and Incline conditions, and 2) mechanical work at the ankle was greater in the High and Incline conditions than in the Low and Decline conditions. Thus, increased knee extensor muscular activity may increase the energy expenditure, and the stretch-shortening contraction of the gastrocnemius muscle may be more efficient
SPRINT RUNNERS\u27 INTENTIONS DURING ACCELERATION AND CHANGES IN THEIR RUNNING SPEED
Full text linkThis study investigated the relationship between intention during acceleration and changes in running speed during a sprint. Changes in running speed over each entire sprint were measured using a laser distance meter (100 Hz). Seven male sprinters performed two sprints with different intentions during acceleration: in one sprint, sprinters were instructed to immediately reach their maximum speed (ACinst), and in the other, sprinters were instructed to sprint 100 m as in a typical sprint race (ACloo). AClm showed significantly higher values for the upper limit of the sprinter\u27s top speed compared to the ACimt. The ACinst showed significantly higher values for initial acceleration compared to the ACiw. These results suggest that changes in running speed are affected by the intention in the acceleration
CONSISTENCY IN STROKE SYNCHRONISATIOM PATTERNS OF CREW-BOAT (K2) SPRINT KAYAKING OVER A FOUR-WEEK PERIOD
Full text linkThe purpose of this study was to compare the stroke synchronisation patterns of a sprint kayak crew (two-seater K2) over a four-week precompetition period. This case study centred on two female paddlers from a national sprint kayak team. High-speed (120 Hz) sagittal-view videos were recorded of a 200-m timetrial each week, for four weeks. Video analysis identified the extent of stroke synchronisation within the crew at four key positions of the stroke cycle (catch, immersion, extraction and release). Results showed similar patterns of offset across the four sessions, whereby the back paddler was either in time or slower to reach the catch position (91% of all strokes analysed), but faster to reach the release position (81% of all strokes analysed). It is likely that an experienced sprint kayak crew may be identified by their stroke synchronisation pattern
DYNAMIC DETERMINANTS OF THE UPPER TORSO ANGULAR VELOCITY IN GOLF SWING
Full text linkThe purpose of this study was to clarify the dynamic components of the upper torso angular velocity about its longitudinal axis during golf swing. Six right-handed golfers hit a golf ball to the net. Three dimensional kinematic data of swing motions were collected using motion capture system. The dynamic components of the upper torso angular acceleration during swing were calculated as a function of I)jo int toque, 2) gravity, 3) gyro-moment, 4) motion-dependent force, and 5) ground reaction forces. The present study found that the torso joint toque most contributed to the upper torso angular acceleration about its longitudinal axis. On the other hand, the shoulder joint toque and the motion-dependent force of the left arm negatively contributed to the angular acceleration of the upper torso about its longitudinal axis
MUSCLE COORDINATION IN CROSS-COUNTRY SKIING: THE EFFECT OF INCLINE ON THE V2-SKATE TECHNIQUE
Full text linkThis study examined differences In upper (UB) and lower-body (LB) muscle activation of twelve elite Nordic skiers using the V2-skate at two inclines via electromyography (EMG). Subjects roller-skied on a treadmill for two 2-minute bouts, one at moderate grade - high speed and one at steep grade - low speed to keep heart rate equal between bouts. EMG was recorded (1 O-second interval), normalized to maximal isometric voluntary contraction, and analyzed for cycle time, peak and average activation, and within-cycle times for activation onset, offset, and peak activation of each muscle. UB tended to remain active for a longer proportion of the cycle at steeper grades while the opposite was true of LB. UB may play an increased role in the V2-skate at steeper grades independent of intensity, although no significant difference in LB or UB response to grade was found (p < 0.05)
THE EFFECTS OF UPPER LIMBS POSITION ON THE AERODYNAMICS IN SKI JUMPING FLIGHT
Full text linkIn ski jumping, the jumpers are moving with high speed (about 90-100 km/h) in flight phase, so that the fluid dynamics play an important role in their performance. We focused on the effects of the position of the upper limbs of a ski jumper on the fluid dynamics in flight position. The purpose of this study was to contribute to the improvement of flight style from a fluid dynamics point of view. We measured the aerodynamic form (drag and lift) of the flight position by a ski jumper model (H: 1.50 m) to investigate the effect of the hand and arm position on the aerodynamics in ski jumping. These experiments were done in the wind tunnel of Japan institute of Sports Sciences. The results showed that the aerodynamic forces could be changed by the body posture such as the angles of arm and hand
IMPACT FREQUENCY VALIDATION OF HEAD IMPACT SENSOR TECHNOLOGY FOR USE IN SPORT
Full text linkHead impact frequency has been identified as a contributing factor to long-term trauma experienced by the brain. A peak linear acceleration greater than 20g has been proposed as defining a single impact. The purpose of this study was to examine the accuracy of a single head impact sensor to identify 209 impacts under short
EFFECTS OF SHOES MASS ON RUNNING GAIT ANALYSIS
Full text linkThe purpose of this study was to investigate the running gait analysis between different mass of shoes. Eleven male college runners from the physical education department participated in this study. The mass of experimental shoes of this study were 175 g, 255 g, 335 g and 41 5 g. When the weight of shoes increased, the maximum vertical ground reaction force increased. and the footstrike patterns changed to mid-foot strike (MFS). The center of pressure shifted forward, and the runner changed to MFS. The strike index of the strike patterns change to MFS pattern that is self-protection mechanism. Heavy shoes increase ground reaction force, thus might increasing lower extremity injuries risk
VALIDATION OF INERTIAL MEASUREMENT UNITS FOR TRACKING 100M SPRINT DATA
Full text linkWearable micro sensor measurement devices are a promising development in sports technology. This paper presents preliminary data evaluating the accuracy of an inertial measurement unit during 100m sprints against a criterion measure from a tripod-mounted Laveg laser. The inertial measurement units were found to be a valid tool for the analysis of peak velocity (r = 0.92) and average split velocities for splits after the first 10m (r = 0.85 - 0.95). Validation data suggests some caution should be taken in interpretation of the first lorn split (r = 0.32). Whilst data from the two devices for this split were correlated, the inertial measurement unit showed an overestimation for this parameter in comparison to the athlete velocity as measured by the laser. Further in-depth analysis should investigate this period
DEVELOPMENT OF A COMMERCIAL ANALYSIS SYSTEM DESIGNED TO ENHANCE PERFORMANCE OF ELITE SWIMMERS IN STARTS, TURNS & RELAY CHANGEOVERS
Full text linkThis paper will provide information concerning the development of the PAS-S swimming start, turn and relay changeover analysis system, designed to enhance the performance of elite competition swimmers. The objective of this project was to provide a system that is able to be retro fitted into almost any training pool. A predecessor of PAS-S was the Wetplate Swim Analysis system which was developed at the Australian Institute of Sport in a pool specifically designed to accommodate it. The Wetplate System proved to be invaluable in the preparation of elite Australian swimmers for international competition in starts, turns and relay changeovers. However, replicating Wetplate at other training facilities was therefore not an option. This project was initiated to develop the PAS-S analysis system that may be installed to the advantage of swimmers in almost any pool