Analiza sil nog na kajak med vožnjo slaloma – študija primera : magistrsko delo

Konda, Nejc (author), Čuk, Ivan (mentor), Jereb, Blaž (comentor)

Namen pričujoče naloge je bil podrobnejši pregled delovanja sil nog med vožnjo kajak slaloma. Omenjeno področje je v veliki meri neraziskano, kar predstavlja težavo, če želimo poglobljeno razumeti razgibanost sil, ki delujejo na kajakaša in le-te povezati s tehniko veslanja. V nalogi smo razčlenili, prostorsko umestili in primerjali delovanja sil na štirih merilnih površinah – levem in desnem stopalu ter levem in desnem stegnu, med izpeljavo več različnih slalomskih nalog (obrati kajaka, veslanje naravnost) na dveh različnih poligonih (mirna in divja voda). V študiji je, kot merjenec, sodeloval večletni predstavnik slovenske slalomske izbrane vrste. Meritve so bile izvedene v približku tekmovalnih okoliščin. Uporabljena je bila merilna tehnologija podjetja Novatel Loadsol. Ugotovljeno je bilo, da med vožnjo slaloma prihaja do znatnih razlik, kadar govorimo o delovanju in velikosti pritiskov sil, ki delujejo na noge. Rezultati časovnega delovanja posameznih sil (glede na zaveslaj), kot tudi izmerjenih povprečnih doseženih sil med meritvami potrjujejo, da sile ki delujejo na stopala opravljajo poglavitno nalogo pri premikanju kajaka naprej. Sile na stegna imajo z vidika največjih doseženih vrednosti manj pomembno vlogo, so pa za to mnogo bolj pomembne pri uravnavanju kajaka okoli dolžinske in navpične osi. Pri veslanju naravnost je, na obeh poligonih, moč opaziti izrazit pojav rasti sile preko enega stopala in hkraten upad sil preko drugega stopala. V povezavi z izvedbo zaveslaja je, pri veslanju naravnost, na obeh poligonih, jasno viden vzorec pretežno istostranskega delovanja v odnosu roka-noga. V vseh delih izvedbe obratov je jasno vidna poglavitna vloga sil preko stopala, ki deluje na zunanji strani obrata. Tako delovanje označujemo kot pretežno nasprotnostransko. Delovanje sil na stegna je pri izvedbi obratov podobno, kot pri veslanju naravnost. Sile na obe stegni delujejo na mirni vodi razmeroma skladno, na divji opazno manj, z več deli izvedbe kjer zabeležimo popolno neskladje. Ugotovitve, kljub dejstvu, da gre za študijo primera, predstavljajo zanimiv vpogled v svet biomehaničnih zakonitosti vožnje kajak slaloma. Potrebno pa se je zavedati, da rezultati te študije prikazujejo le del celote. Poleg sil nog, imajo pri vožnji slaloma pomembno vlogo tudi sile na sedež in list vesla. V prihodnosti bi bilo koristno oceniti tudi te sile in vse podatke o pritiskih na stopalne in stegenske opore, sedež ter lista vesla povezati s hitrostjo ter povečati število posameznih meritev in merjencev. Poznavanje zakonitosti delovanja sil nog in posledično predvidevanje značilnih kajakaško – slalomskih obremenitev lahko vaditeljem poda smernice za (bolj) smotrno zasnovo vadbenega procesa, obenem pa služi kot orodje za prepoznavanje morebitnih telesnih neskladji.

• Language: Slovenian
• Keywords: sile, noge, kajak, slalom, mirna voda, divja voda
• Work type: Master's thesis/paper
• Typology: 2.09 - Master's Thesis
• Organization: FŠ - Faculty of Sport
• Year: 2023
• PID: 20.500.12556/RUL-145758
• COBISS.SI-ID: 153474307
• Publication date in RUL: 12.05.2023

Secondary language

• Language: English
• Title: Analysis of leg forces acting on a kayak during a slalom run - a case study

Abstract

This case study aimed to provide insight into the action of leg forces during a kayak slalom run. This field is considered to still be unexplored, which poses a problem, when trying to understand the variability of forces acting on the kayaker’s legs in relation to the paddling technique. The aim of this study is to disaggregate, spatially locate and compare the forces acting on the legs on four measurement surfaces - left and right foot and left and right thigh; while performing different kayak specific tasks (turns, straight paddling), on two different slalom courses (flat water and whitewater). This case study was conducted on one male Slovenian national slalom team member. The measuring procedures were performed under a proxy of competitive circumstances. Novatel Loadsol measurement technology was used. The results of the study show significant differences in the forces acting on the legs during different slalom runs. Both: time of force occurrence in relation to the paddle stroke and measured average forces achieved during the paddling confirm, that forces acting on the feet play a major role in the forward motion of the kayak. The forces applied by the thighs have a role of mostly balancing the kayak around its longitudinal and vertical axis. During the straight paddling task an occurrence of increased force on one foot and a simultaneous force decrease on the other foot is observed. In relation to the execution of a single paddle stroke during the straight paddling task, a pattern of predominantly ipsilateral action is clearly evident when considering the hand-foot relationship. During the execution of an upstream turn, we observed a distinctly bigger impact (show by the rising forces) applied by the foot acting on the outside of the turn. Such occurrence is characterized as predominantly contralateral. Forces applied by thighs during the execution of the upstream turns act similar to that of the straight paddling. Forces applied on both thighs act relatively consistent when paddling on flatwater, but much less so, while paddling on whitewater, with several sections of the course, where we observe a complete discrepancy. The findings of this case study add an interesting insight into operation of forces acting during paddling of kayak slalom. However, it is important to realise that presented results show only one part of the picture. In addition to the forces applied by the legs, the forces applied to the seat and the paddle blades obviously also play an important role. Knowledge of leg forces acting during a kayak slalom run and consequent predictability of paddling - specific lower limb loads can provide coaches with guidelines for a more efficient design of the training programme and can serve as a tool for identifying potential (lower) body asymmetries.

• Keywords: forces, legs, kayak, slalom, flat water, whitewater