ELECTROMYOGRAPHIC STUDY OF SOME OF HARM MUSCLES ON BASIC LAWN TENNIS MOVEMENTS

Abstract

INTRODUCTION There are few studies about the action of the superior limbs on basic movements of lawn tennis playing. The m. trapezius (upper fibers), m. pectoralis major (sternocostal portion), m. deltoide (anterior and posterior portion), m. biceps brachii and m. teres major were analysed electromyographicaly during the basic movements of lawn tennis (forehand, backhand and service) in ten tennis player volunteers and ten non-practising volunteers. METHODS AND PROCEDURES The signal were recorded using Beckman type surface electrodes and na 8 channel electromyographer. A time-marker was connected to the 8th channel in order to record the exact moment of the three phases in each movement. RESULTS AND DISCUSSION The tennis players showed higher RMS values than the non-practising volunteers on the m. deltoide (posterior portion) 50.06 mV / 20.01mV; m. bíceps brachii 51.06mV / 42.07mV ; m. pectoralis major (sternocostal portion) 70.05mV / 8.88mV and teres major 33.37mV / 10.67mV. The non-practising volunteers showed higher RMS values only on the m. trapezius (upper fibers) 63.07mV / 111.09mV. There was no significant difference between both groups on the m. deltoide (anterior portion) RMS values. The results above indicate that the tennis players showed a higher electromyographic activity on the analysed muscle perhaps due to the fact that these muscles act strongly on the execution of these type of sportive movement. Support: FAPESP - São Paulo-Brazil