THE BIOELECTRIC ACTIVITY OF MUSCLE PECTORALIS MAJOR IN PRESSING FROM A LYING POSITION

The bioelectric activity of muscle pectoralis major was recorded with the help of surface EMG. The aim of this work was to determine participation of three parts of this muscle in motor task realization i.e. the pressing of a barbell in a lying position. Despite a suitable competitors’ selection (the first class) and a similar way of task realization (the 'bridge' technique) some competitors indicated a large activity in central part of the muscle whereas the others in lower or upper part. Average bioelectric activity of three parts of muscle together, in all subjects, was larger in pressing phase than in lowering phase during the press in a lying position. It may mean, that the way of trial realization is also affected by other factors, i.e. the radius of “bridge” curvature or trajectory motion of barbell

Anodic oxidation of the Ti-13Nb-13Zr alloy

This work presents the results of the investigations on the electropolishing and anodic oxidation of the Ti–13Nb–13Zr titanium alloy. Electropolishing was conducted in the solution containing ammonium fluoride and sulfuric acid, whereas the solution of phosphoric acid was used for anodic oxidation of the alloy. The influence of electropolishing and anodization process parameters on the texture (scanning electron microscopy (SEM)) and chemical composition (X-ray photoelectron spectroscopy (XPS)) of the surface layer was established. Electrochemical impedance spectroscopy in 5 % NaCl solution was used for the determination of the corrosion resistance of the alloy