ISBS (International Society of Biomechanics in Sports): Conference Proceedings Archive
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A LONGITUDINAL ANALYSIS OF CENTER OF PRESSURE IN PREGNANT GAIT THROUGHOUT PREGNANCY AND POST-PARTUM
Get PDFThe changes of physiological and morphological during pregnancy muld lead to gait pattern\u27s changes. The aim of this study was to analysis the variation of pregnancy gait balance. Sixteen healthy pregnant women by choosing were performed during the second and third trimesters and again post-partum. Novel EMED was used for measuring the trajectory of the centre of pressure (COP). The results revealed that COP deviation distance (Dn) significantly increase in third trimester compared with post-partum during the initial contact phase (P=0.038). No differences were observed in the deviation distance of trimesters and postpartum during the forefoot push off phase. This method and results maybe have a new sight to reveal the dynamic stability with advanced pregnancy
LOWER EXTREMITY BIOMECHANICS OF AN ANKLE \u27GIVING WAY\u27 CASE DURING THE DROP LANDlNG
Get PDFThe purpose of our study was to present an accidental ankle \u27giving way\u27 case of a participant with chronic ankle instability (CAI) during drop landing test and compare lower extremity biomechanics with that of the participant\u27s normal landing trials. A 7-camera Vicon system was used to capture motions of the participant drop landing from a 30-cm high box. Ground reaction forces were collected using two force plates. Lower extremity joint angles and moments were generated. Subjective comparisons were made between the giving way trial and normal trials. For the giving way trial, the participant exhibited greater ankle inversion, internal rotation and less hip abduction angle in pre-landing phase compared to the normal trials. In addition, the ankle exhibited greater eversion moment and external rotation moment in the landing phase. Center of pressure was more lateral in the giving way trial. We suggest that a more inverted and internally rotated ankle position before landing may place ankle at a high risk of giving way and sprain for CAI individuals
JOINT LOADING WHILE PERFORMING A SIDE-STEP CUTTING MANOUEVRE ON ARTlClAL GRASS TURF WITH DIFFERENT INFILL DEPTHS
Get PDFThe aim of this study was to determine differences in the joint loadings when performing side-step action on artificial grass turf with different infill depths. Significant changes in the ankle inversion angle (Ankle angle Y; p=0.01; ES=0.73), ankle inversion/eversion moment (Ankle moment Y; p=0.03; ES=0.54) and ankle abduction-adduction moment (Anklemoment Z; p=0.01; ES=0.76) at GRFSeak suggests greater loadings, in particular, at the ankle jint when performing the side-step manoeuvres on artificial grass turfs with thicker infill depths; indicating that all of the lower extremity adaptations to execute the stepside occurs at the ankle rather than the knee. A change in infill depths will cause the body posture to adopt a change in technique when executing the side-step manoeuvre. It is possible that greater joint moments elicited could be of risk to the athletes
COORDINATION VARIABILITY - FORCE RELATIONSHIPS DURING A TEMPO RUN
No full textAs people fatigue, impact force characteristics experienced during running are thought to increase and thus may place the individual at a greater risk for an overuse injury. It is still largely unknown as to how the vertical ground reaction forces may impact the intrasegmental coordination variability, a component in the production of movement which has been linked to adaptability and flexibility. Therefore, the purpose of this study was to determine how load characteristics interact with the coordinative variability during a tempo run at a self-selected pace. Fourteen individuals participated in the study and completed a 25 min run at a high level of exertion (RPE > 14). Results demonstrated that the impact characteristics did not change over time but that coordinative variability changed during he initial portion of the run. This suggests that the participants adapted their coordination variability to counteract the forces incurred during the run
VISUAL FLOW DOES NOT ALTER MUSCLE ACTIVITY DURING TREADMILL WALKING OR RUNNING
Get PDFThe current study examined the effect of visual flow (patterns of visual movement of surroundings) on muscle activity during treadmill walking and running. Participants (n=14 walked (1 -39 m-s4) and ran (2.78 msl) in visual flow and control conditions. Activity of the vastus medalis (VM), biceps fernoris (BF), gluteus maximus (GM ), gastrocnemius (GA), tibialis anterior (TA), erector spinae (ES), mtus abdominis (RA), and C4 paraspinal (C4) were assessed via electromyography (EMG) during each condition. Repeated Measures ANOVA revealed EMG differences (p < 0.05) between walking and running for RA, VM, GM, and BF. There were no differences in speeds for the other muscles, or across the visual conditions for any of the muscles. Visual flow does not alter muscle activity during walking or running
THE EFFECT OF COUNTER MOVEMENT JUMP PERFORMANCE IN MIDDLEAGED ELDERLY PRACTICING TAI-CHI EXERCISE
Get PDFThe purpose of this study was to investigate biomechanical effects of Tal-Chi exercise on the lower-extremity in middle-aged elders during counter-movement jump. Twelve middle-aged elders with regular Tai Chi exercise experience and twelve healthy middle-aged elders participated in this study. Ten Vicon Motion System cameras, two Kistler force plates were used simultaneously to capture the kinematic and dynamlc parameters of standing vertical jumps. Independent samples &test was performed for statistical analysis ( u = .05 ). Since the jump height of Tai Chi group was significantly higher ( p c .05 ). It showed that practicing Tai Chi exercise could effectively slow down the degeneration of the moment and power at the hip Joint. Therefore, middle-aged elders were recommended to engage in long-term Tai Chi exercise
CORRECTING FUNCTIONAL MOVEMENT PAITERNS REDUCES FAULTY RUNNING BIOMECHANICS
Get PDFThe purpose of the study was to determine if 6-weeks of correcting underlying movement patterns (stepping, squatting) would change running gait. 26 runners were screened using the Functional Movement Screen (FMS); those scoring 114121 or having asymmetries qualified for the study. 12 runners underwent pre- and post-motion analysis of their running kinematics beak hip adduction (HADD), hip internal rotation (HIR), knee valgus (KVAL), contralateral pelvis drop (CPD)] and performed corrective exercises based on their FMS results. FMS scores (pre 13 +- 1.2 vs post I 6 +- 1.2 (p less than.001) and KVAL (pre 17.5°+- 8.70° vs post 8.8° +- 9.3°, p=.05) significantly improved. HIR improved (pre 23.9°+- 12.5° vs post 14.5°+5.30, p=.08). HADD and CPD did not significantly change, p>.05. Results show that correcting underlying movement patterns shows promise to train gait in runners
SIDE-TOSIDE ASYMMETRY OF LANDING KINETICS IN HEAVY AND LIGHT BASKETBALL PLAYERS DURING A DROP LANDING
Get PDFThis study examined (1) the effect of body mass on impact forces during drop landings in basketball players, and (2) side-to-side asymmetry in landing kinetics between legs. Thirty male basketball players were assigned into \u27heavy" (n = 15, mass 82.7 i 4.3 kg) or "light" (n = 15, mass 63.1 * 2.8 kg) groups. Players performed five drop landings from a 0.42 m platform. Vertical ground reaction forces for both legs were sampled using two adjacent and embedded force plates. A mixed factorial analysis of variance (Body Mass x Side) was applied to normalised peak force and loading rate variables (a = -05). The left leg experienced higher forefoot peak force (1 5.946, p = .001), forefoot mean loading rate (10.9%, p = .007) and rearfoot mean loading rate (1 1.846, p = .014) than the right leg, suggesting that side-to-side asymmetry exists. No body mass effect was found
AERODYNAMICS OF BASEBALL
Get PDFAerodynamics of a baseball was investigated by both Computational Fluid Dynamics (CFD) and experimental trajectory analysis. Aerodynamic drag coefficients of the ball whose rotation axis direction is corresponding with ball\u27s moving direction, which is called gyro ball, were calculated using CFD in two cases: two seam rotation and four seam one. The results showed drag coefficient of 4-seam rotation is about half of the drag coefficient of Zseam rotation. We performed experimental study using trajectory tracking by high speed video to estimate aerodynamic coefficients. We found two-seam and four-seam rotation balls showed different characteristics in drag coefficient when Reynolds number increased and both drag coefficients differ in Reynolds number 0.8 - 1.8 x l0 5exponent and spin parameter 0.1 2-0.23
THE APPLICATION OF DETREMDED FLUCTUATION ANALYSIS IN RUNNING AND ITS INTEGRATION INTO A REAL-TIME SYSTEM
Get PDFDetrended fluctuation analysis (DFA) provides valuable information regarding both training and injury when applied to running time series. However, there is limited information when applied to recreational runners, or within a real-time environment. Firstly, DFA was applied to the stride time series of select training runs and competitive runs for recreational runners completing a half marathon and full marathon. Results indicate recreational runners maintain similar stride time dynamics in a half marathon, compared to training, however, stride time variability becomes increasingly deterministic during a marathon, compared to training. Secondly, we explore the implementation of DFA in a real-time system and provide evidence to support the use of DFA in running feedback