THE ROLE OF JOINTS OF LOWER LIMB DURING SHOCK ABSORBING PHASE IN RACE WALKING

The purpose of this study was to investigate the role of each joint of the lower limb during the shock absorbing phase in race walking (RW) by comparing it with normal walking (NW) and running (RU). Three active race walkers participated in this study. They performed NW, RW and RU (toe-strike) with self-selected speed in a motion capture laboratory. An optical 3D motion capturing system with two force plates was used. The vertical fluctuation of the center of mass in RW was the smallest among the three movements. The negative power at the ankle and knee joint were hardly detected in RW, however, a relatively large negative power was observed at the hip joint. The negative works of both total and individual joint were obtained by integrating the negative power during the shock absorbing phase. The total negative work in NW (0.14 Wlkg) was the smallest among the three motions. The ratio of the hip joint was greater (36.7%) than the other joints in RW

THE EFFECT OF STANCE WIDTH AND ANGLE ON THE ROTATIONAL RANGE OF MOTION OF PELVIS AND TRUNK

[Background] In golf, snowboarding, etc., the distance between both feet (stance width), the angle of the foot (stance angle) are considered as an important factor for its performance. Those position of the legs (stance) are the empirically coached in the sports field. The purpose of this study was to investigate the influence of stance width and angles on the trunk range of motion and the laterality of the load. [Methods] Eleven healthy males participated as subjects in this study. To measure the maximum trunk rotational range of motion in the posture in which the standing to straightened the leg. In the experimental setting, the stance width was set to 42cm, 52cm wide and the stance angle was varied 5 conditions; the central angle (Odeg), the central angle+-15deg and +-30deg. The central angle was defined as the average of the maximum internal- and external-rotation of hip joint in a static standing. Measurement was used an optical motion capture and the force plate, including 12 units infrared camera. The local coordinate systems were set in the spine (TI, T4, T7, and L1)I). [Result] In the stance angle -30deg, the rotational range of motion of the pelvis and trunk decreased significantly in the stance width 42cm compared to the stance angle Odeg. Effect due to the difference in the stance was not observed. SI (Symmetry Index) of the load increased on the rotation side in accordance with the stance angle increased. The load on the leg of the rotational side in the stance angle +30deg was significantly greater than that in the stance angle -30deg. [Conclusion] It was suggested that the difference in the stance angle changed the trunk rotational range of motion in a static standing

LOWER LIMB MOTOR FUNCTION FOR BODY ROTATION DURING BASEBALL PITCHING

This study was conducted to clarify the mechanism of body rotation by the lower limbs in the baseball pitcher throwing motion. Twenty male overhead baseball pitchers participated in this study voluntarily. All participants threwthree fastball pitches with maximal effort toapitching net located in front of the pitcher. In all, 60 pitching motions were captured. An optical motion capture system and two force plates were used for kinematic and kinetic measurements. The ball speed at ball release, joint angles, joint moments and joint power in lower extremities, moment around the center of mass (COM), and body angular momentum about COM were derived. This study demonstratedthat the body\u27s angular momentum was acquired first around the Z axis (horizontal rotation), then around the X axis (vertical rotation), and finallyaround the Z axis after FFC. Hip joint moment was important for generating each rotation motion

Methodology of biomechanical evaluation of laterality in ski-jumping take-off

　スキージャンプ競技の一連の動作は，主に助走，踏切，飛行および着地の４局面に分類される。この中で着地動作を除くと，ジャンパーの姿勢や動作は左右対称であることが力学的・空気力学的に望ましい。しかし，スキージャンプに関する研究の多くは，左右対称であることを前提条件として分析されており，左右差に関してはほとんど言及されていない。そこで，本研究の目的は，空中姿勢を形づくる上で重要なテイクオフ動作の力学的な左右差を評価する手法を提案することとした。被験者は女子スキージャンパー１名とし，実験室内でシミュレーション・テイクオフ動作を７試技課した。動作分析では，光学式動作分析装置と床反力計を用いて，テイクオフ動作中の両脚の股・膝および足関節の関節モーメントを計測した。下肢三関節の屈伸または底背屈モーメントとパワーから力学的左右差を評価した。左右差の程度を定量化するために，対称性指数を用いた。分析結果から，右脚の床反力が大きく，下肢三関節モーメントもすべて右脚の方が有意に大きいことが示された。対称性指数による左右差の程度評価では，特に膝・足関節に大きな差が確認され，左右差の定量化の有用性が示された。本手法により，関節毎に左右差を定量化でき，今後のトレーニング方針に有用なデータを得られることが示された。　The purpose of this study was to propose the biomechanical method to evaluate thelaterality of take-off motion. One skilled woman ski jumper with right foot preference,participated in this research. Seven simulation take-offs were analyzed using a 6-cameraVICON system and two force platforms in a laboratory. Reflective markers were placedbilaterally on acromion, elbow lateral epicondyle, styloid process of radius, one third on theline between the anterior superior iliac spine and the femur greater trochanter, knee andankle joint lateral aspect and forefoot. From the VICON raw data, the center of gravity,the joint moments and power of hip, knee and ankle joints were calculated. Paired t-testswere performed to determine significant differences (p<0.05) between right and left limbvalue. The symmetry index was also obtained due to quantify the degree of the laterality.There were some significant differences between right and left value. In variables showingof the significant differences, the right side showed alwaysgreater value than the left side.Significant differences between right and left are shown in all variables except for the hipjoint power. The symmetry index of knee and ankle joint were particularly big. From theseresults, the main cause of the laterality of this subject might be regarded as the moment of theknee and ankle joint. The technique proposed in this study could evaluate the asymmetry ofa joint moment during simulation take-off movement quantitatively

Ring-Opening Polymerization of Hemoglobin.

Hemoglobin (Hb), an oxygen-carrying protein, has an α₂β₂ tetrameric structure that dissociates reversibly into two αβ dimers (α₂β₂ ⇄ 2αβ). We synthesized a cyclic Hb-ring monomer with two β subunits bound through a 10 kDa polyethylene glycol (PEG) chain. The monomer induced ring-opening polymerization to produce a supramolecular polymer via intersubunit interaction of αβ dimers of an Hb molecule at the PEG terminals. Both the ring-closed monomer and the ring-opened supramolecular polymer were then fixed covalently by intramolecular cross-linking of two β subunits. Quantification of fixed products at various monomer concentrations revealed the equilibrium constant (K), a ratio of propagation and depropagation rate constants, as 5.68 mM⁻¹. The average degree of polymerization (DP) increased proportionally, concomitantly with the initial monomer concentration. Hb polymer with DP = 13.2 (Mn = ca.1 MDa) was obtained by cross-linking at 2.33 mM. Our novel strategy of ring-opening polymerization of Hb will eventually realize a highly aligned and efficiently polymerized Hb for creating artificial oxygen carriers for a clinical use.This document is the Accepted Manuscript version of a Published Work that appeared in final form in Biomacromolecules, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://doi.org/10.1021/acs.biomac.8b01789

EFFECT OF FOOT ROTATION ANGLE ON TRUNK ROTATIONAL STRENGTH AND PHYSICAL QUANTITY TO ROTATE THE BODY

The purposes of this study were to investigate the influence of foot rotation angle on trunk rotational strength and physical quantity to rotate the body. Ten healthy males participated in this study who exerted the maximum trunk rotational strength in a standing posture on the conditions of five different foot rotation angles based on “the central angle” that was defined as the average of the maximum internal- and external-rotation of hip joint in a static standing. The force was measured by force gauge sensor. Biomechanical analysis was performed with an optical motion capture system and two force plates. No significant difference was observed in the rotational strength between any conditions, but as the foot rotation angle increased externally, the free moment acting on the right foot decreased and the moment around the center of mass by the ground reaction forces acting on both feet increased

The Additional Magnetic Anisotropy Induced by Magnetic Anneal in Ferromagnetic Face-Centered Cubic Solid Solutions : Part I. Dependence of the Induced Magnetic Anisotropy on the Temperature and Duration of Magnetic Anneal, on the Measuring Temperature, and on the Alloy Composition in Face-Centered Cubic Nickel-Cobalt Alloys

We have studied systematically the character of the induced magnetic anisotropy in face-centered cubic Ni-Co alloys, using a torque magnetometer designed specially for high-temperature measurements. Specimens used are polycrystalline disks of 10.57, 20.78, 30.84, 40.67, 50.17, and 60.20 %Co-Ni alloys and (110) disk single crystal of 12 %Co-Ni alloy. The results and conclusions obtained are as follows : -The magnetic anisotropy energy, E_u, induced by magnetic anneal is uniaxial. Generally, as the duration of magnetic anneal increases, E_u increases nearly exponentially and, as the temperature of magnetic anneal becomes higher, the rate of development of E_u increases but its saturation value decreases. The development of E_u can not be described in terms of single relaxation time and the associated relaxation times become longer as the duration of magnetic anneal increases. The dependence of E_u\u27 on the temperature, Θ, of magnetic anneal and on the measuring temperature, T, can be expressed well by an expression E_u=const. ×{ (I_Θ/I_0)^2/Θ} (I_T/I_0)^2 where I_Θ, I_T, and I_0 are the values of saturation magnetization at Θ(°K), T(°K), and 0°K, respectively, which was derived by Taniguchi and Yamamoto from the so-called directional order theory. The comparison of the measured data on the alloy composition dependence of E_u as corrected for the composition dependence of the Curie temperature with Neel\u27s theoretical formula indicates that the ordering energy of Ni-Co alloys is negative and hence the alloys may be of the precipitation type. In connection with this study, the temperature dependence of the cubic magnetocrystalline anisotropy constants, K_1 and K_2, was measured with 12 %Co-Ni alloy and pure nickel, and it has been found that, as the temperature rises, K_1 of 12 %Co-Ni alloy changes from positive to negative at about 150℃, while K_1 of nickel takes small positive values above 200℃ and that K_2 of 12% Co-Ni alloy is always positive, while K_2 of nickel changes from positive to negative at about 100℃

EFFECT OF FOOT ROTATION ANGLE ON THE ROTATIONAL RANGE OF MOTION OF TRUNK AND PELVIS

The purposes of this study were to investigate the effect of foot rotation angle on the rotational range of motion (ROM) of trunk and pelvis. Eleven healthy males participated in this study who performed a maximum rotation of the trunk in a standing posture on the conditions of five different foot rotation angles based on “the central angle” that was defined as the average of the maximum internal- and external-rotation of hip joint in a static standing. Kinematic and kinetic analysis was performed with an optical motion capture system and two force plates. The ROM of the pelvis segment decreased significantly on the conditions of -30deg or +30deg compared to the ROM on the condition of the central angle. The load on the foot on the rotating side increased and the free moment decreased as the foot rotation angle increased externally

Ferromagnetic Domain Structure as Affected by the Uniaxial Anisotropy Induced in a 40 Percent Co-Ni Single Crystal

We have found that the domain structure in the annealed state of a 40 percent cobalt-nickel single crystal is very fine and complicated as compared with those of ordinary ferromagnetic crystals but it becomes simpler and larger after quenching from above the Curie temperature. This can be explained as follows : Since the domain structure may in general be fine and complicated at temperatures just below the Curie temperature, domain walls must displace to establish a more stable domain configuration as the temperature lowers. But, this process is suppressed appreciably at relatively low temperatures, because, in solid solution, the ferromagnetic uniaxial anisotropy is induced, in compliance with the domain distribution, by the anisotropic distribution of atoms at high temperatures and the domain wall displacement can take place only by being accompanied by the redistribution of atoms which can not occur at low temperatures. While, in quenching, the specimen crystal is cooled down so rapid that the uniaxial anisotropy and hence the anisotropic distribution of atoms can not be induced, and thus the quenched specimen crystal behaves just as ordinary ferromagnetic crystals. It is shown that these findings together with the results of considerations reported previously lead us to the conclusion that the perminvar-type magnetic properties are due to the stabilization of domain walls by the induced uniaxial anisotropy in f. c. c. solid solutions with cubic anisotropy constants of any sign and b. c. c. solid solutions with negative cubic anisotropy constants

EFFECT OF POSTURAL CHANGE ON THE AERODYNAMIC CHARACTERISTICS DURING TAKEOFF IN SKI JUMPING

The 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's 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