This excellent study and resulting paper is landmark for the analysis and interpretation of countermovement jump performance. The definitions of the various phases of the jump are implemented in our Ballistic Measurement System Software.
The findings are that increased RSImod performance (i.e., greater explosiveness) in collegiate men’s basketball players was best predicted from a temporal perspective by shorter unloading and concentric times. From a rapid force production perspective, increased explosiveness in this population was best predicted by increased unloading and braking RFDs. Strategies favoring shorter movement phases could be ideal for quick improvements in explosive abilities, because they would return a shorter TTT and result in a higher RSImod score even when JH remains constant.
Strategies favoring greater unloading and braking RFDs seem important, although comparisons between high and low RSImod groups suggests that a greater braking RFD, a quicker concentric phase duration, or both should be initially targeted by poor jumpers.