This suggests that for improving vertical jump height, increasing high - velocity hip strength is probably going to be the most beneficial tactic. (strengthandconditioningresearch.com)
Smith machine squat training improves vertical jump height and sprint running ability (De Hoyo et al. 2015b). (strengthandconditioningresearch.com)
The acute effects of dynamic and ballistic stretching on vertical jump height, force, and power. (completehumanperformance.com)