Besides, a significant decrease in plantar flexion was noted during the dolphin kick at the four measured
time points. The internal rotation angles were only significantly decreased at the time point of
maximal plantar flexion and the time point of maximal supination. The tape did not restrict internal
rotation at the highest point and lowest point, because the ankles were not in a maximal internal rotation
position. Since no significant correlation could be established between the ankle flexibility and
the velocity, but a restriction in the flexibility did decrease swimmers’ velocity, we still believe that
flexibility influences swimmers’ dolphin kick performance. We assume that no significant correlation
could be demonstrated because our study population was relatively small and homogenous in terms
of ankle flexibility. The goniometric measurements, already showed that most subjects had extremely
high values for plantar flexion and internal rotation ROM. Since restriction decreased the performance,
we assume that subjects with limited flexibility in the ankle joint might benefit from flexibility exercises
especially toward plantar flexion.