선택한 단어 수는 입니다.
최소 단어 이상 선택하여야 합니다.
최소 단어 이상 선택하여야 합니다.
선택한 단어 수는 30입니다.
최대 10 단어까지만 선택 가능합니다.
최대 10 단어까지만 선택 가능합니다.
제안 방법
- The participants received the start signal from the LED light to prepare their batting motion and performed the batting motion simultaneously with another LED signal. All participants performed batting motion until 3 sets of batting motion data necessary for the study were collected.
- For collection of data on PMT of body muscles, a 16-channel EMG equipment was used (Delsys Trigno wireless EMG system, sampling frequency = 1,000 Hz, gain = 1000, input impedance > 10 Ω, CMRR > 100 dB). All participants performed batting motion using a batting tee, while light emitting diodes (LEDs; Visol Ink., Korea) were used as visual stimulation to signal the start of batting. An A/D box signaling device (VSAD-102-32C, Visol Ink.
- Prior to performing the batting motion, the participants were informed of the objectives of the experiment and instructed to wear black spandex shorts. The participants were given 10 min for stretching and batting practice.
- Prior to batting motion, the electrodes were placed and EMG data were measured for approximately 2 sec with the participants in upright posture. The participants received the start signal from the LED light to prepare their batting motion and performed the batting motion simultaneously with another LED signal. All participants performed batting motion until 3 sets of batting motion data necessary for the study were collected.
- Prior to performing the batting motion, the participants were informed of the objectives of the experiment and instructed to wear black spandex shorts. The participants were given 10 min for stretching and batting practice. In this period, the swing trajectory of the bat was observed.
- The purpose of the present study was to compare the bat speed, body segment rotational velocity, and PMT of upper and lower body muscles during batting motion between college baseball players and amateur baseball players. Both groups showed peak angular velocities in the lowest to highest order of pelvis, trunk, and bat during batting motion, while amateur baseball players group showed significantly lower pelvis, trunk, and bat angular velocity and bat speed than college baseball players group.
대상 데이터
- The participants in the present study were 10 elite college baseball players with no history of musculoskeletal problems in the past 12months (mean age = 22.2 ± 0.9 years, height = 179.9 ± 4.4 cm, mass= 82.1 ± 6.9 kg) and 10 amateur baseball league players with at least 3 years of experience (mean age = 26.2 ± 2.5 years, height = 173.4 ± 3.7 cm, mass = 75.7 ± 4.1 kg).
데이터처리
- SPSS 18.0 (SPSS Inc., Chicago, USA) was used to perform independentsamples t-test for comparison between the groups (elite college baseball players and amateur baseball players) using the peak bat speed, rotational angular velocity of pelvis, trunk, and bat, and PMT of 16 muscles in the lower body and upper torso data acquired during baseball batting motion (α = .05).
이론/모형
- Three-dimensional coordinate data from the reflective markers attached to the body and bat during the batting motion of the participants were filtered using a second-order Butterworth low-pass filter (Winter, 1990), with the cut-off frequency set to 6 Hz. During baseball batting, peak bat speed and peak rotational angular velocities of the pelvis, trunk, and bat that appear over all phases of batting were calculated using the Cardan orientation method, which involved differentiating relative orientation of distal segment coordinate system to proximal segment coordinate system by time.
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