THE VALIDITY OF VELOCITY MEASUREMENT DURING UPPER-BODY RESISTANCE EXERCISES UNDER VARIABLE LOADS

The purpose of this study is to compare the velocity of the barbell with the criterion of the velocity of the center of gravity during the explosive bench press lift with different loads. Fifteen highly trained soccer players participated in this study. Three-dimensional upper extremities kinematic data during the bench press were collected. Participants lifted loads of 10, 30, 50, 70 and 90% of one repetition maximum (1RM) with maximal velocity. All upper extremity segments and barbell were modeled as frustra of cones while the barbell was modeled as a cylinder. One way repeated ANOVA revealed that peak barbell velocity was significantly higher with 10, 30 and 50% and the mean barbell velocity was significantly higher with 10 and 30% of 1RM. Additionally, kinematic methods based on the barbell velocity measurement overestimate the velocity of the center of mass

EVALUATION OF MECHANICAL POWER OUTPUT MEASUREMENT IN A BENCH PRESS EXERCISE UNDER VARIABLE LOAD

The study is aimed to investigate evaluation of mechanical power output measurement during bench press exercise by methods which are used at training practice. As the criterion of power output measurement evaluation we selected a method which estimates the output by means of empirical 3D mechanical model (work in progress)

THE INFLUENCE OF EXTRA LOAD ON TIME AND FORCE STRUCTURE OF VERTICAL JUMP

Extra load is very often used in the training for development of explosive strength. Some research works are focused on a problem of take-off activity in relationship to extra load (Nelson & Martin, 1985; Bosco et al., 1984 and others). The main aim of this study was to find how the extra load influences time and force curve of the vertical jump

THE ANALYSIS OF GAIT IN INDIVIDUALS WITH TRANSFEMORAL AMPUTATION USING A BIONIC KNEE DESIGN: A CASE STUDY

Walking is the body´s natural means of moving from one location to another. It is also the most convenient means of traveling short distances (Perry, 1992). Approximately 4500 new amputations of lower extremities are performed annually in the Czech Republic. Worldwide, 200 – 500 million major amputations are performed each year. Major limb amputations of lower extremities account for approximately 85% of all cases of amputations (Ellis, 2005). The loss of a lower extremity causes the inability to walk without a prosthetic aid. Biomechanics has an important place in the multidisciplinary team, which is essential for the complex care of amputees (Janura, Svoboda, Kozakova, & Birgusova, 2006). New prosthetic designs may enable people with transfemoral amputation perform sports (running) activities in the future. However, it is necessary to master walking with a prosthesis first. The aim of our study is to describe the selected biomechanical parameters of gait in patients with a two-year experience with a bionic knee

Effects of two neuromuscular training programs on running biomechanics with load carriage: a study protocol for a randomised controlled trial

Background In recent years, athletes have ventured into ultra-endurance and adventure racing events, which tests their ability to race, navigate, and survive. These events often require race participants to carry some form of load, to bear equipment for navigation and survival purposes. Previous studies have reported specific alterations in biomechanics when running with load which potentially influence running performance and injury risk. We hypothesize that a biomechanically informed neuromuscular training program would optimize running mechanics during load carriage to a greater extent than a generic strength training program. Methods This will be a two group, parallel randomized controlled trial design, with single assessor blinding. Thirty healthy runners will be recruited to participate in a six weeks neuromuscular training program. Participants will be randomized into either a generic training group, or a biomechanically informed training group. Primary outcomes include self-determined running velocity with a 20 % body weight load, jump power, hopping leg stiffness, knee extensor and triceps-surae strength. Secondary outcomes include running kinetics and kinematics. Assessments will occur at baseline and post-training. Discussion To our knowledge, no training programs are available that specifically targets a runner’s ability to carry load while running. This will provide sport scientists and coaches with a foundation to base their exercise prescription on

Badanie biogennych i nie-biogennych wytrąceń żelaznych z siarkowodoru

Metabolism of sulphate-reducing bacteria (SRB) generally consists of organic substrates or molecular H2 oxidation and sulphates reduction under anaerobic conditions. By oxidizing low molecular weight organic compounds (e.g. lactate, acetate) they obtain energy and nutrients. Biological-chemical process based on the ability and activity of these bacteria to reduce sulphates results in hydrogen sulphide creation which binds with metal cations in solutions to insoluble precipitate forms. In anoxic sedimentary environment with iron redundancy the amorphous iron sulphide is often the initial sulphide phase to be formed and exhibits poor crystallinity in the form of small crystal sizes and short-range crystal order. Although many studies have focused on the mineralogy and surface chemistry of the more crystalline and more thermodynamically stable sulphides such as pyrite and pyrrhotite, an understanding of the crystal habit and surface chemistry of the more poorly crystalline Fe sulphides is critical in assessing their reactivity and the potential for transformation to more stable phases. The aim of this work was to study the properties and composition of biogenic precipitated materials synthesized in reagent bottles with SRB culture under specific laboratory conditions and modified growth media. The modification consists of iron ions addition in form of sulphates and organic substrate dose. In two cultivation modes were by bacterially produced hydrogen sulphide precipitated 4 biogenic samples. The realisation of abiotic control experiments without SRB results in 4 non-biogenic samples production. All created materials were examined by EDX, SEM and XRD. The composition of samples varies according to cultivation and growth media composition. The biogenic precipitates contain greigite, mackinawite and sulphur, non-biogenic samples consist of vivianite.Metabolizm bakterii redukujących siarczany (SRB) składa się generalnie z utleniania organicznych substratów lub molekularnego H2 oraz redukcji siarczanów w warunkach beztlenowych. Poprzez utlenianie molekularnych składników organicznych (np. mleczan, octan) zyskują one energię oraz pożywki. Proces biologiczno-chemiczny oparty na zdolności i aktywności tych bakterii do redukcji siarczanów daje efekt w postaci utworzenia siarczku wodoru, który wiąże się z kationami metalu w roztworach do nierozpuszczalnych form wytrąceniowych. W sedymentacyjnym środowisku beztlenowym z redukcją żelaza, amorficzny siarczek żelaza często wstępną fazą siarczkową, która zostaje utworzona i wykazuje słabą krystaliczność o małych rozmiarach cząstek i słabym uporządkowaniu. Chociaż wiele badań było poświęconych mineralogii i chemii powierzchni bardziej ukrystalizowanych i bardziej stabilnych termodynamicznie siarczkom, takim jak piryt czy pirotyn, zrozumienie zachowań kryształu i chemii powierzchni słabiej ukrystalizowanych siarczków żelaza jest bardzo małe, zwłaszcza w kwestii oceny ich reaktywności i potencjału do transformacji w bardziej stabilne fazy. Celem tej pracy było zbadanie właściwości i składu biogenicznego wytrącanych materiałów wiązanych następnie w butelkach reakcyjnych z kulturą SRB w specyficznych warunkach laboratoryjnych i przy modyfikowanych warunkach rozwoju. Modyfikacja polegała na dodawaniu jonów żelaza w formie siarczków oraz dawki substratu organicznego. W dwóch trybach kultywacji 4 próbki biogeniczne były wytrącane dla siarczku wodoru utworzonego przy udziale bakterii. Realizacja kontroli abiotycznej eksperymentów bez udziału SRB dało efekt w postaci czterech nie-biogenicznych próbek. Cały utworzony materiał był następnie badany przy użyciu metod EDX, SEM oraz XRD. Skład próbek różnił się w zależności od kultywacji i składu ośrodka rozwoju. Wytrącenia biogeniczne zawierały greigit, makinawit oraz siarkę, nie-biogeniczne próbki zawierały wiwianit

Preparation of magnetic iron minerals using sulphate-reducing bacteria

Zastosowanie metabolizmu bakterii redukujących siarczany jest jedną z metod przygotowania siarczków. Jest to metoda biologiczno-chemiczna bazująca na zdolności bakterii do redukcji siarczanów do siarkowodoru, który łączy się z kationami żelaza (II) tworząc nierozpuszczalne osady - siarczki żelaza. W pewnych warunkach wzrostu bakteryjnego biogeniczne siarczki żelaza mogą posiadać cechy magnetyczne. Celem pracy jest zbadanie właściwości magnetycznych i składu biogenicznych siarczków żelaza zsyntezowanych w kulturach bakterii redukujących siarczany w warunkach laboratoryjnych.Using the sulphate-reducing bacteria metabolism is one of the methods of iron sulphides preparation. It is a biologicchemical method based on the ability of these bacteria to reduce sulphates to hydrogen sulphide, which binds with ferrous cations to form insoluble precipitates - iron sulphides. Under certain bacterial growth conditions biogenic iron sulphides can be magnetic. The target of this work was to study the magnetic properties and composition of biogenic iron sulphides synthesized in cultures of sulphatereducing bacteria under specific laboratory conditions and modified growth media