Med Laser  
The Effect of Differences in Warm-up and Muscle Contraction Methods on Muscle Activity and Total Work during the Bench Press Exercise
Hwan Jong Jeong1, Byung Kwan Kim1, Gi Seon Yoo2, Ki Hong Kim3
1Sports Science Institute, Dankook University, Cheonan, Korea
2Physical Education, Dankook University, Cheonan, Korea
3Department of Recreation and Leisure Sports, Dankook University, Cheonan, Korea
Correspondence to: Ki Hong Kim
Received: March 4, 2022; Accepted: March 15, 2022; Published online: April 14, 2022.
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Background and Objectives
During resistance exercises, varying performances may result depending on the effects of warm-up exercises such as the mobilization of motor units and the type of contraction used. This study was conducted to analyze the variations in muscle activity and total work according to the changes in the contraction method of the warm-up performed before executing the 75% 1RM (One Repetition Maximum) bench press exercise.
Materials and Methods
Eight male subjects in their 20s were selected for the study. Two warm-up contraction methods (isotonic contraction, isometric contraction) were performed. For this exercise, three sets of the 75% 1RM bench press were performed. The muscle activity during the warm-up and the main exercise and the total work during the main exercise were measured and the following results were observed.
First, during the warm-up and main exercise, the muscle activity using the isotonic contraction warm-up was higher than that of the isometric contraction warm-up method. Second, the total work using the isotonic contraction warm-up method was higher than that of the isometric contraction warm-up.
It can be concluded that the isotonic contraction warm-up can be an effective warm-up method.
Keywords: Bench press; Warm-up; Muscle contraction method; Total work; Electromyography (EMG)

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