Influence of learning rowing technique on biomechanical variables achieved on different rowing frequencies
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Željko Rajković, Darko Mitrović, Duško Ilić, Vladimir Mrdaković, Srećko Jovanović
University of Belgrade, Faculty of Sport and Physical Education.

indent Abstract
The experiment was done on a sample of 44 students of the fourth year of The Faculty of Sport and Physical Education in Belgrade with no previous rowing experience, of average age 25±2 years, average weight 81±8 kg, and average height 184±7 cm. It lasted ten weeks, three times a week (according to the program of learning basic rowing technique in summer term). Elementary rowing technique was learned in a school boat "Galija" with twelve seats on flat water. No suggestions were made to the subjects about using specific force distribution or length of stroke. Rowing machine "CONCEPT II" was used for gathering basic data (on initial and final test). Stroke parameters in real time were measured by "FITRO ROWER" instrument "WEBA SPORT", and they were processed on programme "SOFTWARE EXPERT 1.2". Thirteen different biomechanical parameters of the stroke were measured: drive time (m/s), recovery time (m/s), rhythm (%), accomplished rowing frequency (stroke/min), power average during the entire stroke cycle (W), power average during the drive time (W), power peak (W), force average during the entire stroke cycle (N), force average during the drive time (N), force peak (N), handle velocity average (m/s), handle velocity peak (m/s), stroke length (cm). The test consisted of three measurements with assigned rowing frequency of 24, 28 and 32 strokes per minute. Significant change was noted in all measured variables. The biggest decrease of variation coefficient was noted on the variables of force and power. Increase in the frequency of rowing led to significant changes in all measured variables, in that way that their variation coefficient decreased. Teaching rowing technique in "Galija", its big mass and big hydrodynamic resistance of water represent disadvantages when learning duration of active and passive phase, as well as the rhythm of rowing. These disadvantages will become the advantages when the values of force and the power of stroke are learned. The results in the final measurement showed that stroke length was the variable which was learned first. The biggest progression was noted with the variables of power and force. It is proved that the frequency of rowing is the important factor in learning rowing technique. Learning should start at lower frequency, and soon change to the frequency of 32 strokes per minute. The results show that we can also discuss faults in rowing technique depending on variability of tested stroke parameters.

keywords ROWING / LEARNING / FORCE / POWER / VELOCITY / STROKE LENGTH / VARIABILITY