ISBS (International Society of Biomechanics in Sports): Conference Proceedings Archive
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CONTRIBUTION OF FORWARD AND VERTICAL IMPULSES DURING MAXIMAL 5OM SPRINTING TO THE MAXIMUM RUNNING VELOCITY IN SPRINTERS
Get PDFThe present study developed a 50 m-forceplate system and examined relationships between the impulse calculated from ground reaction force (GRF) from start to 50m and the maximum running velocity (Vfmax). Thirty five male sprinters performed maximal sprint on the system, using starting block. The forward and vertical components of impulses (IMPf and IMPv. respectively) were computed far each support phase by integrating the GRF. The highest correlation coefficients for both IMPf(~0.736)a nd IMPv(r=-0.729) were found at the distance of 10 m from the start. These results indlcate the ability to keep lMPv low and lMPf high seems to be important for achieving greater Vfmax, notably in the initial stage of acceleration phase
STEP EXERCISE OR VERBAL AND VISUAL EXERCISE AFFECT COG, KINEMATICS AND PERFORMANCE DURING DECELERATION: RANDOMIZED CONTROLLED TRIAL
Get PDFThe purpose of this study is that investigate if step skill exercise or verbal and V i a l exercise affect the height of center of gravity (COG), kinematics and performance during deceleration. Sample size are 24 people (step skill exercise, n= 12; Verbal and visual exercise,n=12) . In the result, step skill exercise increased knee joint flexion angles in stop and deceleration. Furthermore step skill exercise decreased the height of COG only deceleration. However step skill exercise increased performance time ( reaction time) and had a negative impact
Kinetic analysis of fingers during fastball and curveball pitches
Get PDFThis study aims to reveal the function of fingers during fastball (FB) and curveball (CB) pitches of a male adult who had played university baseball pitcher by conducting kinetic analysis on throwing motion with a link-segment model including finger segment. There was no apparent difference in the timing of peak finger joint angle between FB and CB pitches. Peak finger adduction toque in CB pitch occurred just More ball release. In addition, there was an apparent difference more than 30 ms in the timing of peak finger flexion and abduction toque between FB and CB pitches. Previous comparisons of kinematic data for shoulder and elbow revealed similarities between FB and CB pitches. These results suggest that skilled pitcher may minimize visible distinguishing characteristics among pitches and generate different amounts of ball spin at release among pitches adjusting the timing of peak finger torque
INFLUENCE OF APPROACH SPEED AND DISTANCE ON BIOMECHANICS DURING SINGLE-LEGGED RUNNING VERTICAL JUMP
Get PDFThe purpose of this study was to look into the kinematics, kinetics and EMG of the single legged running vertical jumps in different approach speed and distance. 12 basketball player performed single-legged running vertical jumps with 2 approach speed and 3 distance randomly. Kinematic and Kinetic data were collected by a force and 11 infrared high speed cameras. EMG data were recorded by Delsys surface EMG system. Two-way repeated measures AMOVA (2 speeds x 3 distance) was used for establishing differences (significance level p< .05). The jump height, jumt moment of lower extremity, knee power and the activation of tibialis anterior and gastrocnemius were found significantly larger in fast approach speed. We suggested using fast approach speed and 9m approach distance to enhance the single-legged running vertical jump ability
RELATIONSHIP OF BASE-RUNNING PERFORMANCE WITH RUNNING DIRECTION AND ITS CHANGE
Get PDFThe purpose of this study was to clarify whether the running direction and its change affect the base-running performance. Thirty-five male baseball players performed 54.86 m (180 ft.) straight-line sprinting and distance-matched base-running, during which two dimensional positions of players were recorded with B Y Sports Tracking System. The results of this study revealed that the total base-running performance was probably affected by the running performance of the later running phase. In addition, smaller direction change before the first base and larger direction change after the first base maybe responsible for better performance in the entire base-running through better performance in the later section. These results would be useful for players and coaches who attempt to improve base-running performance
EFFECT OF POSTURAL CHANGE ON THE AERODYNAMIC CHARACTERISTICS DURING TAKEOFF IN SKI JUMPING
Get PDFThe purpose of this study was to quantify the aerodynamic characteristics during takeoff using computational fluid dynamics (CFD). The CFD method adopted for this study is based on Large-Eddy Simulation. Body surface data were obtained by 3-D laser scanning of an active ski jumper. A model was generated by dividing the data into A 5 segments with joint mobility. Based on video analysis of the actual takeoff movement at a jumping hill, two sets of motion data were generated (world-class jumper A and less-experienced junior jumper B). The incoming velocity was set to 23.23 m/s. The aerodynamic force, flow velocity, and vortices for each model were compared between models. Comparison of the two models shows that aerodynamic forces acting upon models might be influenced by the airflow condition around the model\u27s back. Expansion of the low air-speed domain of jumper B can be caused by a large trunk angle of attack (Meile et al., 2006). The trunk and upper arm motion might cause the flow structure difference of the wake. Two distinct vortexes generated by the arms produced a downwash flow in the wake of jumper A. It is considered that the positioning of the arms in a very low position strongly influences the flow structure. These results suggested that the vortexes generated by the arms seem to be very important for the aerodynamic lift generation
RELlABlLlTY AND VALIDATION OF AN INERTIAL SENSOR USED TO MEASURE ORIENTATION ANGLE
Get PDFThis study examined the reliability and validity of an inertial measurement unit (IMU) for measuring orientation angle. An IMU was mounted onto a goniometer and moved through 0-90\u27 with data collected at 10\u27 increments. The process was repeated 10 times for all 3 axes. Reliability was measured via a typical error (TE) analysis from the 10 repeated trials. Validity was determined via a Pearson correlation and an ordinary least products (OLP) regression. The lMU was very reliable for all 3 axes (TE: x=0.03", y=0.03", z=0.02").T he Pearson correlation between the IMU and goniometer was large and significant for all 3 axes (r = 1.00,95%CI = 1 .O-1.0). The OLP regression showed no proportional bias for the 3 axes and only small fixed blas for the x and z axes. Overall the IMU tested was very reliably and accurate at measuring orientation angle
ACCURACY IN DETERMINING KINETIC PARAMETERS WITH FORCE PLATES EMBEDDED UNDER SOIL-FILLED BASEBALL MOUND
Get PDFWe developed a force measurement system embedded in a soil-filled mound for measuring ground reaction forces (GRF) acting on baseball pitchers and examined the accuracy of determining the point of force application (PFA) and kinetic parameters computed from GRF. Three 1.0 x 0.9 m2 force platforms were placed on the concrete foundation of an indoor sports facility and three bays were fixed onto the aluminum plates of the force plateorms. In each tray, clay-blocks were laid tightly and a mixture of red sand and volcanic-ash was used to make a smooth surface layer. The mean absolute error was 6.0 f 4.0 mm in determining PFA, less than 15.5 Ns (5% of the true value) in determining linear impulse. These results suggest that the present method is valid for measuring the PFA and GRF acting on the pitcher\u27s legs for analyzing kinetics of pitching performances
EFFECT OF LATERALLY MOVEABLE PEDALS (BIUS) ON KINEMATICS, PEDAL FORCES AND MUSCLE ACTWIN IN RECREATIONAL CYCLING
Get PDFThe purpose of this study was to investigate the effect of a laterally moveable pedal on the kinematics, kinetics and muscle activity in recreational cycling compared to cycling with a standard pedal on an ergometer. Four healthy participants cycled at 100 W and 200 W at 80 rpm with a standard and the BIUS pedal. Kinematics, kinetics and muscle activation have been measured in both conditions. No differences were found regarding the joint angles and in the lateral movement of the pedal. Some differences were partly observed for the ground reaction forces and the muscle activation pattern. In the ergometer setting the BIUS pedal does not lead to kinematic changes of the cycling movement, but causes effects on pedal forces and muscle activation
LOWER LIMB JOINT AND MUSCLE FORCES DURING SLOPED WALKING AT SELFSELECTED SPEED
Get PDFThe aim of this study was to analyse lower limb joint and muscle forces during level and sloped walking. Male participants (n=18, 27+-5 y, 1.80+-0.05 m, 75+-8 kg) walked at -speed at level and on a ramp (+-18"). Joint and muscle forces were analysed using a musculoskeletal model. Downhill walking increased maximum tibiofemoral and patellofemoral compression forces and decreased ankle compression forces, while uphill walking increased all analysed lower limb joint forces. Muscle forces were altered during sloped walking. Amongst others, downhill walking increased quadriceps (>248%) and decreased gastrocnemii (less than 63%) muscle forces in comparison to level walking. Uphill walking increased mean quadriceps (>57%) and gastmnemii (>40%) muscle forces. Results might be used for the development of rehabilitation and training procedures