COMPARATIVE ANALYSIS OF MUSCLE ACTIVITIES DURING RESISTANCE EXERCISES USING VARIABLE AND ELASTIC LOADS

Over the last few decades, many resistance training devices and methods have been deve'loped for the purpose of increasing strength~ One of the most popular devices being used is variable resistance training (VRT) device (Baechle & Groves, 1992). This type of exercise machines has a major advantage that, by altering the shapes of cams, the resistance profiles at different joint positions can match the strength curve (maximum torque-angle curve) of a joint motion. Despite this advantage, the method has not been perfected and there are arguments against its effectiveness (Garhammer, 1989; Ward, 1993). The major disadvantages of this device are the relatively high cost and large space required. The elastic band exercise device such as elastic tubing is getting popular in recent years, especially in rehabilitation settings. To a certain extent, an elastic exercise device has characteristics similar to a variable resistance-training device. The major advantages of this device are its safety, inexpensiveness, and compact design. To evaluate the stresses placed on different upper arm muscles during a biceps curl using selected home exercise devices, it was the purpose of this study to examine the electromyographic (EMG) activities of the pectoralis major, biceps brachii, triceps brachii, and brachioradialis muscles during biceps curls using a VRT device and an elastic tubing

SPEED AND STROKE CYCLE CHARACTERISTICS DURING THE 100-M RACE FOR PARAPLEGIC ATHLETES

The purpose of this preliminary study was to evaluate the speed changes and selected stroke cycle characteristics during the 100-m wheelchair race for paraplegic athletes. Four male and two female T4 and one male and 3 female T3 wheelchair racers served as the subjects. Two S-VHS camcorders (60 fields/s) were panned horizontally to cover the first and second 50 m of the 100-m race, respectively. The maximum speeds recorded ranged from 5.53 m/s to 7.66 m/s. The distance and time needed to reach the maximum speed ranged from 43.9 m and 11.2 s (a T4 female) to 82.2 m and 18.9 s (a T3 female), respectively. The subjects in this study have lower maximum speeds than able-bodied runners and they need longer distance and time to reach their maximum speeds when compared their able-bodied counterparts

THE EFFECTS OF WEARING ROLLER SHOES ON MUSCLE ACTIVITY IN THE LOWER EXTREMITY DURING WALKING

Roller shoes have become increasingly popular among children and its features of retractable wheels which allow the user to walk or roll without changing the footwear. Maintaining balance during forward walking with roller shoes is not an easy task. To prevent falling backward, the user needs to lock the knees and tighten the ankles and thighs while the upper body is slightly leaning forward. Constant walking with roller shoes forces the user to walk in a manner much different from normal gait. Prolonged exposure to un-natural stresses on human body forces our body to evolve by strengthening those incorrect and temporary functions (Clement et al., 1981). For children, the chronic stress may lead to serious injuries in the lower extremity later in life. If any potential of injury exists in a movement it is critical to examine the associated muscle activity that may lead to injury. To the best of our knowledge, the effects of wearing roller shoes on muscle activity in the lower extremity have rarely been studied, especially in the youth population. Thus, the purpose of this study was to compare muscle activity in the lower extremity during walking wearing jogging and roller shoes

DIRECTIONAL CONTROL IN TENNIS SERVES PERFORMED BY ELITE PLAYERS

This study quantified the pre-and post-impact 3-D kinematics of the ball and racquet during the serves that landed at different locations performed by five male and four female professional tennis players. Data were collected during competition using two high-speed cameras (200 Hz). Two first serves .-one landed near the center line and the other near the side line --were analyzed for each subject. A 2 x 2 ANOVA (0 < .05) was performed for each parameter. The results indicate that the males had significantly greater post-impact ball and racquet velocities than their female counterparts. Though not statistically significant, the ball tended to travel to the left less during the toss and have lower post-impact velocity for serves that landed near the side line. Altering the toss might be one of the strategies used by players to control ball direction in the serve

KINEMATIC ANALYSIS OF GOLF SWING PERFORMED WITH INTENDED LATE HITTING

The purposes of this study were to analyze and compare the kinematic parameters for standard and purpose golf swings. The purpose golf swing is characterized as intended late hitting and increase displacement of ball through the air (carry). Twenty-five male college golfers were recruited as sUbjects and Science eye field 3 camera system was used to measure the parameters of deterministic model. Paired t-test was used to compare between two different golf swings and correlation coefficients between selected parameters and carry were also computed. As results, a significant difference between standard and purpose golf swings was found in terms of increasing carry. Coefficients of correlation indicated that post-impact ball velocity, pre-impact club head velocity, and meet rate were positively correlated with carry. However, backspin, and angle of release were negatively correlated with carry. These results represented that the parameters of deterministic model were very useful indicators to determine performance and the purpose swing is beneficial to increase carry

EFFECTS OF GENDER AND FOOT POSITION ON ACCELERATION PATTERN OF KNEE AND HIP JOINT DURING DEEP SQUAT

The purpose of this study was to investigate the effect of gender and foot position on the acceleration patterns of the knee and hip joints during deep squat. Twenty-two male and 10 female collegiate students participated in this study. All the participants performed a deep squat two times in neutral foot position (NFP), with the foot rotated externally by 15° (ERFP). A wireless triaxial accelerometer was attached on the right-side knee and hip joints of each participant. Acceleration data generated in the anterior-posterior (AP), medio-lateral (ML), and superior-inferior (SI) directions during deep squat were collected through the attached acceleration sensor (2000Hz). Statistical analysis was performed using SPSS 24.0, and mixed analysis of variance (p \u3c 0.05) was used to identify the interaction and main effects of gender and foot positions. The acceleration patterns of the knee joint during deep squat according to gender indicated differences between the AP and ML directions. The acceleration motion of the hip joint under the ERFP condition indicated a difference in the SI direction

TIBIO-FEMORAL JOINT FORCES DURING THE LANDING PHASE OF DIFFERENT TYPES OF VERTICAL JUMP

The purpose of this study was to compare the tibio-femoral contact forces during the landing phases of 8 different types of vertical jump (squat, countermovement, hop approach and drop jumps each with and without the use of arms). Data were collected from eight males and eight females. Two S-VHS camcorders and a force platform were used to obtain the 3-D kinematics and kinetics of the knee joint. Activities of selected muscles spanning the knee joint were monitored using surface electromyographic (EMG) techniques. The EMG-assisted optimization model was used to estimate the tibio-femoral joint forces. The peak compressive contact forces ranged from 3-5 body weight (SW) and from 2.5-3.7 SW for the males and females, respectively. These loads seldom fell within the range that is considered to be damaging to the cartilage at the knee

THE EFFECTS OF WEARING SPANDEX WEAR WITH COMPRESSION BAND ON MUSCLE ACTIVITY DURING A GOLF SWING

The purpose of this study was to determine how spandex wear with compressive band affects muscle activities during a golf swing. This study showed that average and maximum nEMG (normalized EMG) values of left AO (external abdominal oblique) were less in EG (experimental group) compared with CG (control group) during back swing, whereas those of left PM (pectoralis major) in EG were greater than CG. It is more likely that EG performed effectively golf swing without excess muscle activity. Thus, the spandex wear with compressive band played an important role in improving swing performance with injury prevention. This has led to suggestions of the need for further kinetic and kinematic analyses to evaluate its function

KINEMATIC ANALYSIS OF THE WOMEN’S JAVELIN THROW AT THE IAAF WORLD CHAMPIONSHIPS, DAEGU 2011

The purpose of this study was to analyze the kinematic variables for the women's javelin throw at the IAAF World Championships, Daegu 2011. Three-dimensional motion analyses of the eight players who qualified for the final round were carried out to obtain the data. The results showed that average release, attitude, and attack angles were 38.0±2.0°, 40.4±4.3°, and 3.7±1.1°, respectively. At the release, the average inclination angle of the trunk, upper arm, forearm were 60.8±8.3°, 47.3±10.1°, and 62.6±10.6°, respectively. Moreover, the release velocity and the release height results averaged 25.60±1.16 m/s and 1.86±0.05 m. The crossover phase and delivery phase had average distances of 1.88±0.31 m and 1.53±0.21 m. After release, the average distance between the landing foot and the foul line was 1.72±0.63 m

THE EFFECTS OF WEARING ROLLER SHOES ON GROUND REACTION FORCE CHARACTERISTICS DURING WALKING

Roller shoes have become increasingly popular among children and it features retractable wheels which allowing the user to walk or roll without changing the footwear. Maintaining balance during forward walking with roller shoes is not an easy task. To prevent falling backward, the user needs to lock the knees and tighten the ankles and thighs while the upper body is slightly leaning forward. Constant walking with roller shoes forces the user to walk in a manner much different from normal gait. Prolonged exposure to un-natural stresses on human body forces our body to evolve by strengthening those incorrect, and temporary functions (Clement et aI., 1981). For children, the chronic stress may lead to serious injuries in the lower extremity later in life. If any potential' of injury exists in a movement it is critical to examine the associated forces that may lead to injury. To the best of our knowledge, the effects of wearing roller shoes on ground reaction forces (GRF) characteristics have rarely been studied, especially in the youth population. Thus, the purpose of this study was to compare GRF characteristics during walking wearing jogging and roller shoes