Evaluation of a foot switch system for the maximal instep kick in soccer-results from a single-case study

Abstract
Aim of this single-case study was to investigate the feasibility and the validity of the use of Footswitch System (FS) during maximal instep kick (MIK). One participant conducted 25 MIK’s simultaneously recorded by both systems. The MIK was divided into three time phases and total phase and were measured in milliseconds. Feasibility outcome was the time schedule. Validity was examined with ICC and the Bland-Altman method. Total measuring time was 3 hours and 10 minutes. 27% of 25 MIK’s were usable for evaluation. Systematic biases are determined for all phases. Negative bias for phase 1 (-7.1 ms), phase 3 (- 3.6 ms) and MIK (- 4.9 ms) and positive bias for phase 3 (5.9 ms) are presented. The authors conclude that the actual investigation protocol
is not feasible for measuring the MIK and should be modified.

Key words:
biomechanics, electrogoniometer, three dimensional movement analysis system