In the present Diploma thesis we studied the difference of core strength on ten healthy adult recreational runners during winter training sessions, which included functional training for core and leg strength, and summer training sessions, which were mostly composed of running training. With adapted measuring devices we measured the strength of core muscles during the left and right axial core rotation, left and right side bend and back extension. The measurements were done at the Laboratory for Kinesiology at the Faculty of Sport in the interval of two months.
General improvement of core strength was evident in four out of five measurements (left side bend: 12,0 %; right side bend: 17,1 %; left rotation: 5,7 %; right rotation: 8,6 %) and in nine out of ten subjects. An average core strength improvement was 7,0 %. Positive trend was present in 64 % of all measurements.
The difference between averages as well as rates and trends of individual improvements show the increase of core strength at left and right side bend as and left and right rotation while there was a decline of strength at back extension. T-tests for dependent samples or adequate non-parametric tests at 5 % risk showed the statistic characteristics of difference between measurements before and after the change of the training process in right side bend (z = -2,395, p = 0,017). The other measurements were statistically insignificant (left side bend: t(9) = -1,900, p = 0,090; back extension: t(9) = 1,887, p = 0,092; left rotation: z = -1,275, p = 0,202; right rotation: t(9) = -1,965, p = 0,081). The hypothesis H1 (The core strength after running trainings and running technique drills will be improved in comparison to the core strength after winter training sessions.) was proven to be wrong.