Analisi biomeccanica del MAWASHI GERI JODAN in cinture nere di Karate: modelli tecnici a confronto

In martial arts there are several ways to perform the turning kick . Following the martial arts or different learning models many types of kicks take shape. Mawashi geri is the karate turning kick. At the moment there are two models of mawashi geri, one comes from the traditional karate (OLD), and the other newer (NEW), who agrees to the change of the rules of W.K.F. (World Karate Federation) happened in 2000 (Macan J. et all 2006) . In this study we are focus on the differences about two models the mawashi geri jodan of karate. The purpose of this study is to analyse cinematic and kinetic parameters of mawashi geri jodan. Timing of the striking and supporting leg actions were also evaluated A Vicon system 460 IR with 6 cameras at sample frequency of 200 Hz was used. 37 reflective markers have been set on the skin of the subjects following the “PlugInGait-total body model”. The participants performed five repetitions of mawashi geri jodan at maximum rapidity with their dominant leg against a ball suspended in front of them placed at ear height. Fourteen skilled subjects (mean level black belt 1,7 dan; age 20,9±4,8 yrs; height 171,4±7,3 cm; weight 60,9±10,2 Kg) practicing karate have been split in two group through the hierarchical cluster analysis following their technical characteristics. By means of the Mann Whitney-U test (Spss-package) the differences between the two groups were verified in preparatory and execution phase. Kicking knee at start, kicking hip and knee at take-off were different between the two groups (p < 0,05). Striking hip flexion during the spin of the supporting foot was different between the two groups (p < 0,05). Peak angular velocity of hip flexion were different between the two groups (p < 0,05). Groups showed differences also in timing of the supporting spin movement. While Old group spin the supporting foot at 30% of the trial, instead New start spinning at 44% of the trial. Old group showed a greater supporting foot spin than New (Old 110° Vs New 82°). Abduction values didn’t show any differences between the two groups. At the hit has been evaluated a 120° of double hips abduction, for the entire sample. Striking knee extension happened for everybody after the kicking hip flexion and confirm the proximal-distal action of the striking leg (Sorensen H. 1996). In contrast with Pearson J.N. 1997 and Landeo R 2007, peak velocity of the striking foot is not useful to describe kick performance because affected by the stature. Two groups are different either in preparatory phase or in execution phase. The body is set in difference manner already before the take-off of the kicking foot. The groups differ for the timing of the supporting foot action Trainer should pay attention to starting posture and on abduction capacities of the athletes.

Biomechanical modelling of human knee during living activities

The knee joint is a key structure of the human locomotor system. The knowledge of how each single anatomical structure of the knee contributes to determine the physiological function of the knee, is of fundamental importance for the development of new prostheses and novel clinical, surgical, and rehabilitative procedures. In this context, a modelling approach is necessary to estimate the biomechanic function of each anatomical structure during daily living activities. The main aim of this study was to obtain a subject-specific model of the knee joint of a selected healthy subject. In particular, 3D models of the cruciate ligaments and of the tibio-femoral articular contact were proposed and developed using accurate bony geometries and kinematics reliably recorded by means of nuclear magnetic resonance and 3D video-fluoroscopy from the selected subject. Regarding the model of the cruciate ligaments, each ligament was modelled with 25 linear-elastic elements paying particular attention to the anatomical twisting of the fibres. The devised model was as subject-specific as possible. The geometrical parameters were directly estimated from the experimental measurements, whereas the only mechanical parameter of the model, the elastic modulus, had to be considered from the literature because of the invasiveness of the needed measurements. Thus, the developed model was employed for simulations of stability tests and during living activities. Physiologically meaningful results were always obtained. Nevertheless, the lack of subject-specific mechanical characterization induced to design and partially develop a novel experimental method to characterize the mechanics of the human cruciate ligaments in living healthy subjects. Moreover, using the same subject-specific data, the tibio-femoral articular interaction was modelled investigating the location of the contact point during the execution of daily motor tasks and the contact area at the full extension with and without the whole body weight of the subject. Two different approaches were implemented and their efficiency was evaluated. Thus, pros and cons of each approach were discussed in order to suggest future improvements of this methodologies. The final results of this study will contribute to produce useful methodologies for the investigation of the in-vivo function and pathology of the knee joint during the execution of daily living activities. Thus, the developed methodologies will be useful tools for the development of new prostheses, tools and procedures both in research field and in diagnostic, surgical and rehabilitative fields.

Analisi clinica ed ex-vivo dei punti isometrici durante tecnica tightrope nella ricostruzione del legamento crociato craniale del cane

La rottura del Legamento Crociato Craniale (LCCr) rappresenta una delle patologie ortopediche di maggiore riscontro clinico nella specie canina. In seguito a rottura del LCCr si presenta un continuo slittamento craniale della tibia il quale esita in un processo osteoartrosico. La risoluzione chirurgica rappresenta la migliore soluzione terapeutica. Le tecniche chirurgiche extra-articolari con sfruttamento dei punti isometrici del ginocchio si presentano come delle procedure molto diffuse e utilizzate. Questa tesi propone di validare l’uso di un nuovo sistema di navigazione computerizzato-assistito per la valutazione cinematica durante la ricostruzione del LCCr nel cane, ma soprattutto di studiare e confrontare il comportamento e l’efficacia dopo ricostruzione TightRope (TR) in due diverse coppie di punti isometrici. Abbiamo effettuato due analisi in parallelo. La prima eseguendo interventi chirurgici con tecnica TR su 18 casi clinici e sfruttando il punto isometrico del femore (F2) e due diversi punti isometrici della tibia (T2 o T3). L’analisi prevedeva dei controlli postoperatori a 1, 3 e 6 mesi. Ad ogni controllo veniva effettuata una visita ortopedica, esami radiografici, un questionario di valutazione clinico e di soddisfazione del proprietario. Mentre nella ricerca Ex-Vivo abbiamo eseguito dei test su 14 preparati anatomici con l’utilizzo di un sistema di navigazione computerizzato per la rilevazione dei dati. L’analisi prevedeva la valutazione dell’articolazione in diversi stadi: LCCr intatto; LCCr rotto; dopo ricostruzione con TR in F2-T2 e tensionato a 22N, 44N e 99N; dopo ricostruzione con TR in F2-T3 e tensionato a 22N, 44N e 99N. Ad ogni stadio si eseguivano cinque test di valutazione, tra cui: Test del Cassetto, Test di compressione tibiale (TCT), Rotazione Interna/Esterna, Flesso/Estensione e Varo/Valgo. Lo scopo di tale studio è quello di confrontare tra loro i punti isometrici del ginocchio e di analizzare l’efficacia della tecnica TR nelle due differenti condizioni di isometria (F2-T2 e F2-T3).