Paper 251: Wavelet-EMG Analysis of the Leg Muscles in Fencing During a Flèche Attack

Abstract

Fencing is highly demanding on the coordinative skills of athletes. The timing of the muscular activation during a flèche attack is one factor of a successful touch during an attack in a fencing bout. The goal of this study was to analyze the muscular activation sequences of the main leg muscles during flèche attacks and to help to improve training methods in fencing. Kinematics of the whole body [Romkes et al, 2007Romkes et al.J Pediatr Orthop B. 2007; 16: 175-180Crossref PubMed Scopus (67) Google Scholar] (VICON MX, 240 Hz), ground reaction force during the push-off phase (Kistler, 6000 Hz) and EMG data (Biovision, 6000 Hz, SENIAM-Standard) of the M. Tibials anterior, (TA), M. Gastrocnemius Medialis (GM), M. Vastus Medialis (VM), M. Rectus Femoris (RM), M. Semitendinosus (HAM) of both legs and of the M. Vastus lateralis (VL) of the front leg was recorded of 7 volunteer male expert fencers. The data of 10 trials/subject were averaged using EMG Wavelet-Transformation (WT-EMG) [von Tscharner, 2000von Tscharner J Electromyogr Kinesiol. 2000; 10: 433-445Abstract Full Text Full Text PDF PubMed Scopus (271) Google Scholar]. The test setup simulates a competition situation. The subject was doing small vertical bouncing jumps on the 2 force plates. The start for flèche attack was given by a visual signal at the target. The distance between the force plate and the target was 2.5 m. The beginning of the forward movement of the center of mass was set as movement start (t = 0 sec). The movement was initialized by lowering the center of mass and shifting it slightly in direction of the target. The actual push-off movement started with an activation of the RF, VM and GM of the rear leg. After taking off the rear foot a short co-contraction of the RF and HAM occur to stabilize the position of the hip joint. [Nene, 2004Nene A. Gait & Posture. 2004; 20: 1-13Abstract Full Text Full Text PDF PubMed Scopus (91) Google Scholar]. The push-off movement of the front leg started before the muscular activation of the rear leg was finished. It started with the RF, VL, VM, GM and slight co-contraction of the RF and HAM after the foot left the ground. Prior to landing all measured muscles of the rear leg were activated, a co-contraction was seen for the ankle joint by the GM and TA and for the hip and knee-joint by the RF, VM and HAM. The co-contraction of the RF and HAM after take-off of the rear leg is needed to keep the leg in the desired position. While the co-contraction of the RF, VM and HAM and the TA and GM prior to landing is a mus¬cular pre-activation which is needed to con¬trol angular position of the joint and to ab¬sorb the impact force of the landing of the rear foot after hitting the target. The main landing impact was first absorbed by TA and slight later by GM and VM, with a clear higher muscular activation. The result of this study shows that the flèche attack is a highly demanding movement for the muscular coordination.