In real world settings it is quite rare that a coach will exclusively include or exclude a specific exercise in training. Most coaches are aware of the importance of variety to stimulate various movement patterns and develop specific strength and power. However, in research, the exact opposite is done in order to determine what effect a given exercise has on performance outcomes. For example, in a recent blog post, we discussed research that compared the effects of training exclusively with the hip thrust versus the front squat on athletic performance and strength variables. This type of research provides insight as to the transfer effect that each exercise has. The coach can then use that information to structure their training programs depending on the goals and needs of the athletes. Rarely would the research be intended to encourage coaches to eliminate certain movements. The debate between horizontal and vertical force production being the limiting factor to sprinting speed continues and thus so does the research.
A new study published ahead of print in the Journal of Strength and Conditioning Research compared the chronic effects of vertical versus horizontal drop-jump training in elite team-sport athletes. Twice per week over 10 weeks, the athletes performed a workout consisting of 5-8 sets of 6-10 repetitions of vertical (9 athletes) or horizontal (9 athletes) single-leg drop-jumps from a 25 cm box. Before and after the 10-week training intervention that occurred during the in-season, the athletes were tested in the counter-movement jump and 25 m shuttle sprint (12.5 m sprint, 180 degree change of direction, 12.5 m sprint). Kinetic and kinematic variables were assessed via force plate and time-motion video analysis and compared between groups.
The results showed that all performance, kinetic and kinematic variables improved for both groups, but significant between group effects were also found. For example, horizontal drop-jumping led to greater improvements in change of direction, sprint time, and step length compared with vertical drop-jumping. In contrast, the vertical drop-jump group showed greater improvements in vertical jump height, peak ground reaction force, relative impulse, leg-spring stiffness, contact time and reactive strength index. Thus, each training program resulted in adaptations specific to direction of force application. These results should be interpreted such that both horizontal and vertical drop-jumping should be included in training due to their unique effects on performance.
Antonio, D. I., Martone, D., Milic, M., & Johnny, P. (2016). Vertical-vs. horizontal-oriented drop-jump training: chronic effects on explosive performances of elite handball players. The Journal of Strength & Conditioning Research. In Press.