The aim of the study was to analyse the chronological succession of the neuromuscular activation in high performance gymnasts during different techniques for giant swings on the horizontal bar, measured using a telemetric electromyography system (EMG). It should be examined how to optimize current teaching methods to the special demands of neuromuscular activation patterns during long hang swings. Methods: The sample consisted of three high level gymnasts (male, age: 16-17 years, 28-30 hrs. of training /week). They first had to demonstrate giant swings backward in "conventional technique" (conv.GS, n=11), and then using the high accelerating"power technique" (pow. GS, n=5) (1). The EMG was captured with 1500 Hz (Telemyo 2400T, Noraxon, USA). The following muscles were plotted: Pectoralis major (Pect.), rectus abdominis (RAbd.), rectus femoris (RFem) as essential parts of the anterior muscle chain, and deltoideus, pars posterior (Delt.), erector spinae (ESpin), biceps femoris (BFem) as antagonists (posterior muscle chain). The kinematic data of the elements were captured using video kinemetric analysis with 50 Hz ("2D-Mess" of IAT, Leipzig). For synchronization, the systems were triggered by an analogue signal. Results: During the leg acceleration phase, in all participants and in all elements, the results showed a succession of muscular activation of the anterior chain from "Punctum fixum" (PF) to "Punctum mobile" (PM). Pect. and RAbd. were coactivated nearly simultaneously. RFem. was always activated last, with no exception. During the upswing phase in conv.GS either a simultaneous or even a recurrent succession from PM to PF was found. In contrast to this, the muscle activation and deactivation patterns (anterior and posterior) during all phases of pow.GS ran through the body from PF to PM. Discussion: The results support the thesis that for an effective segmental acceleration of PM the activation has to run from PF to PM, generally. To cause an impulse transmission of PM, however, an inverted pattern seems to be necessary. Thus, the succession of neuromuscular activation does not always correlate with the kinematic succession of segmental body movements (1). With regard to the fact, that training methodology is commonly based on kinematic models this could lead to ineffective patterns of neuromuscular activation and cause a prolonged learning process for developing high level swinging techniques. The findings should be verified in larger samples of high performance gymnasts. If these results are affirmed, then these aspects should be accounted for in training methodology for better differentiation and faster learning of correct muscular activation patterns with regard to long hang swings.
© Copyright 2009 14th annual Congress of the European College of Sport Science, Oslo/Norway, June 24-27, 2009, Book of Abstracts. Veröffentlicht von The Norwegian School of Sport Sciences. Alle Rechte vorbehalten.