EFFECTS OF CUSTOM-MADE 3D PRINTED INSOLES FOR FLAT-FOOT PEOPLE ON GAIT PARAMETERS: A PRELIMINARY STUDY

The purpose of this study was to make low-cost and custom-made 3D printed insoles for flat-foot people and to investigate the feasibility of these insoles in walking and running. Thirty people (15 normal and 15 flat-foot people) participated in this study. 3D scanner, 3D printer, and CAD software were used to produce insoles and motion capturing system and a force plate were used to perform gait analysis. Results indicated that custom-made 3D printed insoles were not effective on joint angles and ground reaction forces, but they affected the trajectory of COP positively during stance phase. Further study with different filling rate and materials of insoles are required to generalize 3D printed insoles for flatfoot people

COMPARATIVE ANALYSIS OF YANG HAK-SEON VAULT AND TSUKAHARA 1260? VAULT IN GYMNASTICS

The study was a single-subject study on the top-elite vaulter in the world. This study was purposed to compare kinematic differences between Yang Hak-Seon vault (Yang-1) and Tsukahara 1260? vault (Yang-2) performed by Yang Hak-Seon. Fourteen high-speed cameras were used to capture a whole body segment motion of Yang-2 vault during the practice session. Yang-1 vault showed faster CM vertical velocity until the vault table takeoff and faster CM horizontal velocity prior to the vault table touchdown. However, the trunk rotation angle and its angular velocity of Yang-2 vault exceeded Yang-1 vault significantly. This might be due to a half turn off the springboard onto the vault table of Yang-2 vault, which resulted in larger initial angular momentum at the vault table touchdown and further increase in angular velocity during the vault table contact

DOSE FASTER HOPPING FREQUENCY IMPROVE RESPONSE TIME AND KICKING SPEED IN TAEKWONDO ROUNDHOUSE KICK?

The purpose of this study was to investigate the effect of rhythmic hopping frequency on the response time and kicking speeds in Taekwondo roundhouse kick. Eleven elementary and middle-school athletes voluntarily participated in this study. They performed five roundhouse kicks at three different hopping frequencies (normal, 15% faster than normal, and 15% slower than normal) and no hop condition. Results indicated that the 15% slower hopping frequency induced a significantly longer response time than the 15% faster frequency. The 15% faster frequency resulted in faster maximum kicking speed than normal frequency did, while there was no difference in contact kicking speed. Partially the faster hopping frequency would be beneficial to kicking performance

EFFECTS OF FOOT PLANTING POSITIONS ON KNEE JOINT IN DROP LANDING

The purpose of this study was to investigate the effect of three different foot placement positions at the moment of foot-ground contact on the knee joint kinematics and kinetics in drop landing in an attempt to estimate the risk of non-contact anterior cruciate ligament (ACL) injury. Three foot placement positions were toe-in (TI), neutral (N), and toe-out (TO) positions according to the heading direction of toes relative to femur. Seventeen college students participated in this study and motion capturing system with forceplatforms was used to assess the drop landings. Toe-in (TI) position should be avoided due to the highest combined loading of valgus and internal rotation. The neutral foot landing position is recommended to minimize the risk of non-contact ACL injury

KINEMATIC COMPARISONS OF KETTLEBELL TWO-ARM SWINGS BETWEEN EXPERTS AND BEGINNERS

The purpose of this study was to investigate kinematic comparisons of kettlebell two-arm swings between experts and beginners in order to find out biomechanical key points for preventing sports injuries and enhancing kettlebell performance. Four experts and three beginners performed kettlebell two-arm swings fifteen times with a 16 kg kettlebell. Experts demonstrated larger ranges of motions (ROM) of pelvic segment and hip joint than beginners, while beginners revealed larger ROM of shoulder joint than experts. Magnitudes and sequential orders of peak angular velocities of major joints were significantly different between two groups. Conclusively, the mobility of pelvic segment and hip joint are required, while the stability of the other joint are needed to produce appropriate kettlebell two-arm swings. The activation and strength of gluteus muscles would be key contributors

EFFECTS OF WALKING SPEED AND AGE ON THE DIRECTIONAL STRIDE REGULARJRY AND GAIT VARIABILITY IN TREADMILL WALKING

The purpose of this study was to assess the directional stride regularity (SR) and gait variability (GV) of data from shoe-type inertial measurement unit (IMU) sensors during levelled treadmill walking. The DynaStabtm (IMU based gait analysis system) including Smart Balance' (shoe-type data logger) was used to collect normal gait data from forty-four subjects in their 20s (n=20), 40s (n=13), and 60s (n=ll). Four different walking speeds (3, 4, 5, and 6 km/h, respectively) on a treadmill were applied for one-minute of continuous levelled walking. Only lateral kinematics (mediolateral acceleration and yawing and rolling angular velocities) revealed significant interactions from walking speed and age, demonstrating lower stride regularity and higher gait variability than the anteroposterior and vertical kinematics

BIOMECHANICAL ANALYSIS OF BACK-SOMERSAULT KICKS IN TAEKWONDO

This study was purposed to investigate biomechanical differences between best and worst trials in performing back-somersault kicks in Taekwondo. Six elite members of college Taekwondo demonstration team participated in this study and executed each ten trials of single back-somersault kick and double back-somersault kick, respectively. High speed motion capturing system collected positions of 21 markers on major anatomical locations to obtain motion data of full body segments. After post-processing procedure, results showed that the best trial of back-somersault kicks indicated longer preparation time (countermovement), larger range of motions of hip joint, and higher peak angular velocities of knee and hip joints prior to take-off than those of the worst trial. We concluded that athletes should avoid a quick countermovement before take-off, which induces insufficient strain energy of lower extremities and ground reaction impulse. Therefore, a sufficient time for muscle contractions are required to develop high power

A Case of a False-Positive Anti-Myeloperoxidase Antibody ELISA in a Patient with Hypothyroidism

We present a case of a false-positive anti-myeloperoxidase (MPO) antibody result on an ELISA in a patient with anti-thyroid microsomal antibody (TMA)-positive hypothyroidism. A 41-year-old woman presented with dyspnea on exertion. The initial evaluation revealed pericardial effusion associated with hypothyroidism. In addition, microscopic hematuria with normal renal function and positive cytoplasmic anti-neutrophil cytoplasmic antibodies (c-ANCA) on immunofluorescent assay were found. In further evaluation, elevated anti-TMA and MPO antibodies by ELISA. While no definite signs of vasculitis were present, the clinical state improved with thyroid hormone replacement and diuretics. Anti-MPO antibody was still positive in the follow-up tests, and microscopic hematuria persisted. On the basis of previous reports that thyroid peroxidase and MPO molecules contain cross-reactive epitopes that are exposed in denaturated molecules, we suggest that in a patient with anti-TMA-positive hypothyroidism, anti-MPO antibody might also be positive on ELISA without clinical signs of vasculitis

Okanin, a chalcone found in the genus Bidens, and 3-penten-2-one inhibit inducible nitric oxide synthase expression via heme oxygenase-1 induction in RAW264.7 macrophages activated with lipopolysaccharide

Excess production of nitric oxide by activated macrophages via inducible nitric oxide synthase leads to the development of various inflammatory diseases. Heme oxygenase-1 expression via activation of nuclear factor-erythroid 2-related factor 2 inhibits nitric oxide production and inducible nitric oxide synthase expression in activated macrophages. Okanin is one of the most abundant chalcones found in the genus Bidens (Asteraceae) that is used as various folk medications in Korea and China for treating inflammation. Here, we found that okanin (possessing the α-β unsaturated carbonyl group) induced heme oxygenase-1 expression via nuclear factor-erythroid 2-related factor 2 activation in RAW264.7 macrophages. 3-Penten-2-one, of which structure, as in okanin, possesses the α-β unsaturated carbonyl group, also induced nuclear factor-erythroid 2-related factor 2-dependent heme oxygenase-1 expression, while both 2-pentanone (lacking a double bond) and 2-pentene (lacking a carbonyl group) were virtually inactive. In lipopolysaccharide-activated RAW264.7 macrophages, both okanin and 3-penten-2-one inhibited nitric oxide production and inducible nitric oxide synthase expression via heme oxygenase-1 expression. Collectively, our findings suggest that by virtue of its α-β unsaturated carbonyl functional group, okanin can inhibit nitric oxide production and inducible nitric oxide synthase expression via nuclear factor-erythroid 2-related factor 2-dependent heme oxygenase-1 expression in lipopolysaccharide-activated macrophages