by GREG INFANTOLINO CSCS | Originally printed in the NSCA TSAC REPORT • ISSUE 04 ￼ JANUARY 2008
In many operational settings the tactical athlete is required to jump onto, over, and down from different obstacles. It is imperative then that these athletes are trained to develop ex- plosive power and eccentric muscle strength. Plyometric, or jump training, is a great way to improve athletic performance in these areas. Training with plyometric exercises makes use of the stretch-shortening cycle, where an explosive concentric muscle action is preceded by an eccentric muscle action (1). This article is going to focus on box jump ups and depth jumps.
The goal in performing box jump ups is to develop explosive power. The first thing to think about when performing box jump ups is the height of the box to be used. Box height should be anywhere from six inches to 42 inches, depending on the athlete’s ability. Once the box height has been selected, the ath- lete stands facing the box with feet shoulder width apart. The athlete then performs a counter-movement jump up, landing softly with both feet on the box. They will then step down from the box and repeat for the prescribed number of repetitions.
Depth jumps are a plyometric exercises that involve a shorten- ing of the hip, knee, and ankle extensors immediately after they have been rapidly and forcefully stretched. This rapid stretch stores elastic energy and triggers the stretch reflex (1). Depth jump training is extremely taxing on the central nervous system and imposes significant stress on the tendons (2). Because of this, an athlete should be able to squat one and a half to two times their own body weight before starting depth jump training. Also, young athletes with less than three to four years of strength train- ing experience should not partake in depth jump training.
Depth jump training is not inherently dangerous; however, there is a risk for injury if done improperly or when the athlete is not ready to start depth jump training. To perform a depth jump, the athlete steps off a box and executes an explosive vertical or hori- zontal jump immediately upon landing. The box height for depth jumps can range from 12 to 42 inches (4). Therefore we start ath- letes with a 12 inch box and gradually increase the box height. It is important to note that the National Strength and Condition- ing Association’s position statement on plyometrics recommends that athletes weighing over 220 pounds should not perform depth jumps from higher than 18 inches (3).
Box jump and depth jump training should be incorporated into the tactical athlete’s training program due to the physical and operational requirements of their job. Developing power and eccentric muscle strength will help the tactical athlete perform their tasks easier and more efficiently, as well as help to reduce injuries that may keep them from partaking in operations.
1 Holcomb, W.R., J.E. Lander, J.E., Rutland, R.M., and Wilson, G.D. A biomechanical analysis of the vertical jump and three modified plyometric depth jumps. J. Strength and Cond. Res. 10(2):83 – 88. 1996.
2 Miyama, M., and Nosaka, K. Influence of surface on muscle damage and soreness induced by consecutive drop jumps. J. Strength Cond. Res. 18(2):206 – 211. 2004.
3 National Strength and Conditioning Association. (1993). Position statement: Explosive/Plyometric Exercises. Natl. Strength Cond. Assoc. J. 15(3):16. 1993.
4 Potach, D.H., and Chu, D.A. Plyometric training. In: Essentials of Strength Training and Conditioning (2nd ed.). T.R. Baechle and R.W. Earle, eds. Champaign, IL: Human Kinetics, pp. 427 – 470. 2000.