INTRODUCTION: Previous studies (Holmberg H. -C et al, 2005 and Holmberg L. J. & Lund A. M., 2007) of double-poling cross-country skiing show that depending on style, load distribution between m. teres major (TM) and m. latissimus dorsi (LD) changes. With a modern "wide elbow" style, TM does more of the work. But, with a classical "narrow elbow" style, LD is the more dominant muscle. In the paper by Holmberg H. -C. et al there is a discussion about elbow joint movement and triceps activation. Their measurements show that skiers using the "wide elbow" style have a smaller minimum elbow angle at pole plant, higher angular elbow-flexion velocity, higher peak pole force and were faster than skiers using the "narrow elbow" style. It is suggested that "wide elbow" style skiers utilize the triceps better due to higher preloading of the muscle. The aim of this study is to find out if there is a difference in work-load for the triceps depending on double-poling style. METHOD: Using the Simulation model from Holmberg L. J. & Lund A. M. and by changing the set-up, three double-poling styles were simulated, ranging from "narrow elbow" to "wide elbow". For each Simulation, the three parts of triceps (m. triceps brachii): caput longum (LH), caput laterale (LA) and caput mediale (ME) were studied. The Simulation model, consisting of a body model and boundary conditions, is implemented in the AnyBody modeling system. Any body is a general musculo-skeletal modeling system based on inverse dynamics. The body model consists of about 452 individual muscles and 29 bones. Boundary conditions (motion and external forces) are used as input to the simulation, and come from an experiment in which a skier was videotaped while skiing on a DP ergometer equipped with load cells at the pole tips. RESULTS AND DISCUSSION: Simulation results show that for a given pole fore, the "narrow elbow" style requires a higher activation of LA and ME than the "wide elbow" style does. This implies that a skier"s available muscle strength in LA and ME can be used more efficiently with the "wide elbow" style. While LA and ME only spans the elbow, LH also work as a shoulder extensor and the difference in activation levels between styles were not that clear. Overall, these results agree well with earlier studies. As always, numerical models of reality contain simplifications and uncertainties. It can be hard to judge how relevant results from such a model are. The simulation model in this study is no exception. CONCLUSION: This study shows that there is a difference in triceps work-load depending on double-poling style and it also confirms the suggestion that it is possible to utilize the triceps muscles better with a "wide elbow* style of double-poling.
© Copyright 2007 4th International Congress on Science and Skiing. Julkaistu Tekijä University of Salzburg. Kaikki oikeudet pidätetään. / Kääntänyt https://www.DeepL.com/Translator