"How is the check mark for the javelin thrower's run-up established, and how should it be adjusted based on different conditions such as surface type, weather, and wind?"
MEASURING THE RUN-UP The check marks for the javelin thrower are as important as those used in the jumping events. The elite thrower knows almost to the centimetre how close he will be to the scratch line. This technique should be practised on every throwing day. To establish a check mark, which is placed at the position where the rhythm must change, the thrower begins 2 steps before the first check mark. The first check mark is hit with the left foot, then the thrower continues for 6 steps to hit the T with the left foot. The T point is the start of the five- count final approach, which includes the cross-step. As the technique of the thrower develops, the run-up will be lengthened by adding two strides at a time. In a longer run-up, the total length of the last 5-stride rhythm will also be longer. KEY: L = LEFT FOOT R = RIGHT FOOT S = START OF APPROACH  = CHECK MARK, T = START OF FIVE-COUNT APPROACH. The athlete should run the full run-up while an observer marks the position of the check marks. This is done six times, and the farthest markers from the scratch line is measured and written down. These distances are measured next to the run-up prior to the competition and tested. Small adjustments can be done according to the specific situations. Keep in mind that the run-up will differ slightly on different approach surfaces, or weather conditions. Running into a headwind will require a shorter run-up and running in a tailwind will require a longer run-up. In bad weather, the run-up must be shortened for better control in the 5-step rhythm.