ISBS (International Society of Biomechanics in Sports): Conference Proceedings Archive
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A STUDY ON THE OPTIMAL DEFENSE POSITION OF HANDBALL GOALKEEPER: FACING A FORWARD JUMP SHOT MADE FROM 9M
Get PDFThe purpose of the study was to derive an optimal defense position for goalkeepers through calculating ideal defense area and actual defense area when blocking forward jump shots from 9 m distance. A total of 9 men\u27s handball matches were captured with 4 digital video cameras from the 94th Korea National Sports Festival with consent from the Korea Handball Federation. Video clips with 78 forward jump shots from 9 m distance which included the whole movements of goalkeeper were analyzed. The ball\u27s speed in the forward jump shot, release point of the ball, goalkeeper\u27s defensive stance, and defensive position were analyzed. The actual defense position of goalkeeper was 1.10*0.37 m and the optimal defense position calculated through the movements of goalkeeper was 1.45 m from the goal line
THE BLOMECHANICAL EFFECTS OF ANTICIPATION DURING A STOP-&-BACK RUN TASK TO SCREEN HIGHRISK ATHLETES FOR NONCONTACT ACL INJURY
Get PDFThe purpose of this study was to determine the role of anticipation on the lower extremity and trunk kinematics, and the height of the center of mass during a stop-&-back run task. Collegiate athletes (n=18) were recruited and completed three tasks; anticipated stop, unanticipated stop, and anticipated stop with a badminton net in front of their face. Three video cameras were used, and the trunk and extremity kinematics, and the height of center of mass (COM) for the second step before the complete stop (deceleration step) and the step of the complete stop (stopping step) were analyzed. At the initial contact of the deceleration step, the height of the COM was greater and the knee position was more posterior in the unanticipated condition than the other two conditions (p less than .05). The results showed the height of the COM was higher during unanticipated stop-&-back run task, which has important implications for future ACL injury screening
EFFECTS OF MASSAGE ON POST-EXERCISE MUSCLE STIFFNESS: PRELIMINARY FINDINGS
Get PDFThis study examined the effects of massage on post-exercise muscle stiffness. Six well trained male runners underwent a 40-minute downhill run and had one leg massaged and the contralateral leg receiving a placebo treatment on the rectus femoris (RF) and tibialis anterior (TA). Muscle soreness perception and stiffness were assessed at baseline, post-run, post-treatment, 24,48, 72, and 96 hours post-run. Muscle stiffness of the RF and TA increased and peaked at 24 hours after the downhill run before a gradual reduction in subsequent days. A more rapid recovery (decrease in stiffness) was oberved in the massaged RF compared with the contralateral leg although soreness perceptions were similar between legs for both muscles. Massage might be effective in reducing stiffness of muscles that are larger in size and that experience greater soreness post-exercise
HIP KINEMATICS AND MUSCLE ACTIVITY DURING INSIDE SOCCER KICK IN PLAYERS WITH A HISTORY OF GROIN PAIN
Get PDFThe purpose of this study was to clarify the kinematic characteristics of groin pain (GP). In addition, we investigated the correlations between the kinematics of inside soccer kick movement and muscle activities in the lower extremities. Twenty-four male soccer players (control group, 13; GP group, I1 ) were instructed to perform maximum inside kick. Our results showed that the adductor muscle activity was maintained from the back swing to the leg acceleration phase in the in GP group but was decreased from the peak value at the back swing to the leg acceleration phase in the control group. In the leg acceleration phase, the adductor muscle activity was significantly higher in the GP group than in the control group. The GP group showed faster adduction/abduction velocity of the kicking leg in all kicking phases than the control group
VALIDATION OF A DXA-BASED METHOD FOR OBTAINING INERTIA TENSORS: \u27WHEN PIGS FLY\u27
Get PDFThis paper examines the accuracy of body segment inertia tensors estimated by combining information from dual-energy X-ray absorptiometry and a three-dimensional modelling technique proposed by Zatsiorsky et al. (1 990) (DXAIVol method). The inertia tensor of a frozen pig cadaver was estimated using the novel DXAlVol method and traditional compound pendulum techniques. The pig cadaver was projected through the air and the experimental \u27ground truth kinematics\u27 were recorded. Simulated kinematics of the pig cadaver flight were generated using the inertia tensor derived from the DXAlVol and compound pendulum methods and compared to the ground truth kinematics. Simulations based on the novel D W o l method\u27s inertia tensor traded the experimentally recorded flight of the frozen pig cadaver with superior accuracy
Estimating Hydrodynamic Forces Acting on the Hand during Sculling in Synchronized Swimming
Get PDFThe characteristics of the hydrodynamic farces acting on the hand at different loads during sculling in synchronized swimming was estimated using a pressure distribution measuring method. One cycle of flat scull in a back layout position and support scull in a vertical position for one female national-level synchronized swimmer were analyzed. Results showed, at small loads in the flat scull, larger hydrodynamic force was observed during out-scull. As load increased, the hydrodynamic force increased during in-scull, and the values were observed to equalize between in-scull and out-scull. At all loads in the support scull, the larger value was observed during in-scull. It was apparent that in both sculls, the hydrodynamic force increased as the load increased, and the pressure on the dorsum of the hand decreased when large hydrodynamic force was generated
THE REORGANIZATION OF THE NEUROMUSCULAR SYSTEM DURING AGEING: INFLUENCE OF REGULAR PHYSICAL ACTIVITY
Get PDFSenescence is accompanied by various changes affecting the neuromuscular system that contribute to the decline in functional performances observed in elderly individuals. In addition to a profound remodelling of the neuromuscular system, several mechanisms located at both muscular and neural levels contribute to this lost of performances. Hopefully, regular physical activity may counteract or reverse some of the alterations encountered in old age. The purpose of this keynote lecture is to give an overview of the main age-related changes of the neuromuscular system and to evoke the potential influence of regular physical activity in limiting these alterations
MARKER REGISTRATION FOR INVERSE KINEMATIC MODELS OF THE UPPER LIMB: IMPORTANT CONSIDERATIONS FOR THE SPORT SCIENTIST
Get PDFThe scaling of rigid-linked skeletal models is an important consideration for researchers looking to calculate joint angles via inverse kinematics (IK). It has been suggested (Dunne et al., 2013) that registering marker positions with known kinematics during scaling can improve the accuracy of IK derived lower limb joint angles during gait. The purpose of this manuscript was to determine if registering marker positions with known joint kinematics can improve the accuracy and reliability of time varying IK derived elbow flexion/extension (FE) estimates during cricket bowling. Registering marker positions and joint kinematics (MKR) resulted in improved accuracy than marker positions only (MR) (RMSE = 8.9° v 25.1°) when compared with known DK derived elbow angles. The inter-tester reliability of MKR model elbow extension range was also superior (ICC = 0.626 v 0.318)
A COMPARISON OF TWO BODY SEGMENT PARAMETER MODELS VIA ANGULAR MOMENTUM AT TAKEOFF IN DIVING
Get PDFThe angular momentum production during the takeoff phase in diving was computed in two ways: The first approach used the Hanavan model based on 15 landmarks. The second one was an image-based individual model. The remote angular momenta of the body segments were computed and compared. It turned out that both methods yield almost the same angular momenta of the total body. Depending on the body mass the arm segments amount to 52 ± 6 % to the total angular momentum for the individual model and 57 ± 9 % for the Hanavan model. The leg contribution was 33 ± 6 % and 33 ± 7 %, the head contribution was 19.1 ± 4 % and 14.2 ± 4 % for the individual model resp. for the Hanavan model
LAGRANGIAN MULTIPLIER / MATRIX PARTITIONING APPROACH FOR THE SOLUTION OF THE MUSCLE LOAD DISTRIBUTION PROBLEM
Get PDFThe paper presents a musculoskeletal biomechanical model which resides in the Simulink / MATLAB environment and is suitable for the analysis of sporting activities. The model can be used to calculate ground reaction forces, muscles, joint and skeletal component loadings. The model is currently being used at over 150 research institutions and because of its short learning curve is especially suitable for undergraduate teaching. The calculation of the muscle loading distribution is calculated by minimising an objective function. The optimisation approach implemented uses a Lagrangian multiplier technique and is supplemented by a matrix partitioning method to apply inequality constraints. This technique is capable of calculating the muscle force distribution in near real time using the limited resources of a laptop computer