Reliability of metrics associated with a counter-movement jump performed on a force plate

The counter-movement jump is a consequence of maximal force, rate of force developed, and neuromuscular coordination. Thus, the counter-movement jump has been used to monitor various training adaptations. However, the smallest detectable difference of counter-movement jump metrics has yet to be established. The objective of the present study was to measure the reliability of counter-movement jump metrics, including rate of force development, flight time, time to max force, and max force. Twenty-nine male participants (mean age 25 ± 3 years) were divided into three groups. Each participant performed five counter-movement jumps on a force plate, on three consecutive days. Flight time detected trivial changes, (effect size < .2) and typical error of measurement of .25%; max force detected small changes (effect size < .5) with a typical error of measurement of .3%; rate of force development detected small to medium change (effect size .5–.8) with a typical error of measurement of .3%.