Figure 4. Functional model of leg and monofin movements based on the mutual relations between horizontal swimming speed and the groups of features, techniques of monofin and leg movements (level I) and the parameters which directly (level II) and indirectly (level III) influence swimming speed. Arrows illustrate relations between elements of the model, lines indicate the parameters describing the elements of the model on its various levels, depending on the relations from the influence on swimming speed.