水中レジスタンス運動の基本動作における下肢の筋活動水準 : 陸上での実施時との比較

Abstract

[Aims] The water resistance exercise （WRE） is a muscle strength training performed using the viscous resistance of water. However, which muscle gets activated and the activity level during WRE remain unclear. The purpose of this study was to compare the muscular activity level of the leg when performing basic movements of WRE in water and on land, and thus, investigate the characteristics of muscular activity during WRE. [Methods] Subjects were 8 female aqua-exercise instructors. Electromyography （EMG） data of the leg （total 6 muscles） when performing the basic 3 movements of WRE [leg extension（LE）, leg curl（LC） and hip adduction （HA）] in water and on land using the same tempo, were collected using a waterproof-type telemetric electromyograph. The EMG data in each movement was normalized by the EMG data at the maximal voluntary contraction of each muscle, and the muscular activity level （%EMGmax） was evaluated. [Results and Discussion] In water, while the activity level of the agonist in HA reached 30%EMGmax, the agonist of LE and LC were at approximately 20%EMGmax. It was considered that the subjects of the underwater resistance motion exercise targeted in this study did not reach the load strength enough to expect the muscle strength improvement effect. In addition, in the operation with one leg standing, the level of muscle activity of the thighs to maintain the posture was higher than the muscle as the training object. Even with the same motion and tempo, different muscle activity was observed between underwater receiving viscous resistance of water and land on which gravity load is applied.