THE KINEMATIC ANALYSIS OF THE LUMBAR, LUMBOSACRAL, AND HIP JOINTS IN THE DOLPHIN KICK SWIMMING

INTRODUCTION: The dolphin kick movement is commonly used in swimming. The low back pain (LBP) while using the dolphin kick motion is complained by many swimmers and that greatly influences their performance. Cailliet (1968) stated that LBP is caused by kinematic problems in the lumbar, the hip joint and the pelvis. Thus, the kinematic analysis that was included includes the pelvis, the hip joint as well as the lumber vertebrae was necessary for the prevention of the LBP. However, underwater analysis of the dolphin kick was not enough to explain the injury mechanism. Therefore the purpose of this study was the kinematic analysis of the lumbar, the lumbosacral, and the hip joints in the dolphin kick

Relationship between reaction Time And Onset of The Muscle Activation During Drop Landing

Quickness is one of very important factors for athletes in sporting activities. Measuring reaction time reflects how quickly they can move by contracting associated muscles. Reaction time consists of the pre-motor time, as the time from stimulus input to the onset of the muscle activation, and the motor time, as the time from the onset of the muscle activation to the point of body motion begun. In 2004, Demont et al. were reported that a neuromuscular feed forward process as measured by preactivation of the muscle to stabilize joints dynamically during drop landing. This contributed to prevent injuries. Both time of pre-motor and preactivation were the muscle activities that occur before the body motion begins. The purpose of this study was to clarify the relationship between reaction time and onset of the muscle activity during drop landing

MUSCLE ACTIVITY IN THE SUBJECTS WITH FUNCTIONAL INSTABILITY OF THE ANKLE DURING A SINGLE-LEG DROP JUMP

Ankle sprain is one of the most common injuries experienced sporting participation, and Hertel J (2002) reported it’s recurrence rate is very high( 47-73 %). Presence of residual pain and functional problems (recurrent complaints of “giving way” or repeated sprain) following inversion ankle sprains are often reported. These symptoms of repeated complaints of “giving way” and/or recurrent sprains have been termed functional instability (FI) of the ankle joint with the report of Freeman, Dean and Hanham (1965). Including the report of Konradsen and Ravn (1991) and Hertsell and Spaulding (1999), There are many studies of muscle functions such as muscle strength, muscle activity, muscle response time of ankle joint evertor in the subjects with FI of the ankle joint. However, a few studies have researched muscle activity in the situation actually occurs ankle sprain such as jump landing on the subjects with FI of ankle joint. The purpose of this study was to identify differences in ankle joint muscle activity in subjects with FI of the ankle joint during a single-leg drop jump landing

RELATIONSHIP BETWEEN ANTERIOR TIBIAL TRANSLATION AND ISOMETRIC STRENGTH IN FEMALE ATHLETES

The purpose of this study was to determine whether the isometric strength of the muscles around the knee and hip is associated with anterior tibial translation. Forty-four female high school basketball players participated in this study. Anterior tibial translation was measured with a Kneelax 3 arthrometer. The isometric strengths of knee flexion, knee extension, and hip abduction were determined with a hand-held dynamometer. In the case of both the legs, significant correlations were found between the anterior tibial translation, knee extension strength, and hamstring/quadriceps strength (H/Q) ratio. No significant correlations were found between the anterior tibial translation and the knee flexion and hip abduction strengths. Muscle imbalance between the quadriceps and hamstring muscles may lead to greater anterior tibial translation

RELATIONSHIP BETWEEN REDUCED OF MEDIAL LONGITUDINAL ARCH HEIGHT AND KNEE VALGUS

Knee valgus during jump landing is considered to be one of the situations that may cause injury to the anterior cruciate ligament (ACL). Decreased muscle torque during hip abduction is also reported to be a causative factor for knee valgus, as is pronation of the ankle joint (Joseph M et al. 2008). Further, knee valgus may occur when a reduction in the height of the medial longitudinal arch causes ankle pronation, leading to tibial inclination angle to the inside. In this study, motion analysis was performed to investigate the relationship between a reduction in the height of the medial longitudinal arch and knee valgus

DETERMINING AN EFFECTIVE STRETCHING TIME FOR ACHILLES TENDON EXTENSION

Stretching exercises are commonly undertaken for sports and rehabilitation. However, it is unknown how an in vivo muscle-tendon unit responds to added stretching stimulation. The purpose of this study was to determine an effective stretching time for Achilles tendon extension. The human medial head of the gastrocnemius muscle was stretched and ultrasonography was used to determine and then compare the length of the Achilles tendon between before and after stretching. Achilles tendon extension for one minute of stretching was 3.4±2.5mm, two 6.8±2.1mm, three 6.9±1.0mm, five 7.2±0.7mm, and ten 7.4±0.8mm. Achilles tendon length was significantly increased for up to two minutes of stretching (

THE DIFFERENCE OF THE BALANCE ABILITIY BETWEEN THE FUNCTIONAL ANKLE INSTABILITY AND HEALTHY SUBJECTS

Ankle inversion sprains are one of the most common injuries occurring in sports activities. Repeated ankle sprains may lead to chronic ankle instability. In order to prevent the occurrence of ankle instability, it is necessary to understand the difference in the physiological characteristics of the subjects who have chronic ankle instability and those who do not. However, there is little known about the differences between the two. It has been reported that there are two types of ankle instability: mechanical ankle instability (MAI) and functional ankle instability (FAI) which is the disability to which patients refer when they say that their foot tends to “giving way”. In this study, we have attempted to uncover the difference in the center of pressure (COP) and muscle activities during a single leg standing between FAI subjects and healthy subjects with or without an ankle brace

RELATIONSHIP BETWEEN MUSCULAR OUTPUTS AND THE HORIZONTAL PERTURBATION IN THE EARLY PHASE OF BENCH PRESS MOVEMENT UNDER STABLE AND UNSTABLE CONDITIONS

We demonstrated the relationship between the change rates of muscular outputs and horizontal perturbation under stable and unstable conditions in dynamic bench press movement. Twenty-seven male collegiate athletes attended the study. We used a tri-axis accelerometer attached to the barbell shaft to obtain the acceleration data in the bench press and computed peak force output, rate of force development (RFD), and horizontal acceleration trajectory length for 0.2 seconds after the initiation. Significant reduction was found in the peak force output and RFD under stable and unstable conditions, but not in the horizontal acceleration trajectory length. Significant correlation was found between the change rate of RFD and the horizontal acceleration trajectory length under stable and unstable conditions (r=0.55,