FATIGUE EFFECTS ON SHOOTING ARCHERY PERFORMANCE

Abstract

As archery competitions normally last many hours requiring a great deal of shoots, the athletes are usually subjected to a deterioration of muscle performance Deterioration of mechanical performance of one or more muscles, which are not able to maintain longer the desired force level, may be related to technique and motor strategy changes Although these modification are probably very subtle, their effect may produce undesirable impact on arrow scores It was the purpose of this study to analyse the possible effect of muscular fatigue on strategy used by athletes to accomplish the task. An additional objective was to determine whether or not fatigue effects are somewhat dependent on skill level of athletes. Twelve archers of Italian Archery Federation were the subjects of this study. According to their FITA scores they were classified as intermediate (n = 7; FITA scores ranging from 1.180 to 1300) and top level archers (n = 5; FITA scores > 1300). 15 shoots for each archer were recorded and analysed at firstly. After these measurements a fatigue protocol was performed. The athletes come to a full drawing position and remained in the aiming phase for 20 s. Each athlete performed six series of ten repetition with rest interval of 20 s. between the sets. Immediately following the fatigue protocol, the subjects performed other 15 shoots. EMG, kinematics and force platform data were acquired and processed using the ELITE motion analysis system An electrical device attached to the bow was used to detect the moment of clicker closure, arrow release. and contact-loss of the arrow with the bowstring Surface EMG was collected from the finger flexor muscles and biceps of the drawing arm and from upper and lower back muscles, with a sampling rate of 1000 Hz. Markers were placed on. the temporal bone and the mandibular joint to mark the head: the shoulders. elbows. wrists and hands to mark the arms; the iliac crests, knees. ankles, and third metatarsal heads to mark the lower limbs. In addition. three markers were placed on the backbone and other three were attached to the bow. Ground reaction forces and centre of pressure displacements were measured with a Kistler force platform at a sampling rate of I000 Hz. In each subject no significant variation in performance scores was evident. In all the subjects a significant increase in bow lateral sway were observed after the fatigue protocol. The increase was much more evident in less skilled subjects. Furthermore, the results showed that less skilled subjects displayed longer aiming phase duration after fatigue protocol.