In my last post in this series I described the appropriate amount of external resistance that should be applied to box jumps, if external resistance is to be applied at all. But, seeing as there are numerous possible ways to go about adding this extra resistance, we need to differentiate which methods of external resistance are most effective. Dumbbells, elastic bands, and weighted vests will all be discussed.
Dumbbells are commonly seen being held while an athlete performs box jumps. The problem with dumbbells is that they affect the athlete's ability to use their arms efficiently while performing the jump. The altered movement pattern this produces is most noticeable at the beginning of the movement, but can also be equally detrimental to the athlete's landing mechanics. Because the external resistance is attached to a moving limb and inhibits that limb's ability to produce force, dumbbells are not the way to go if you are wanting to load a box jump.
Elastic bands that attach from the floor to the person's waist, as can be seen on someone using a Vertimax trainer, are another means by which vertical jumping, but not necessarily box jumps, is loaded. The problem with this, as I'm sure you can tell, is that the heaviest resistance from the bands occurs once the person has left the ground and is at the peak of their jump height in the air. The bands, therefore, have their greatest influence in the eccentric aspect, causing someone to land faster than they normally would without the bands as the bands recoil and resume their original length. Considering the amount of pounding that occurs to the joints during the course of any sports season, I do not feel it is the best interest of the athlete to use elastic bands in order to improve jumping performance as the bands will only cause greater impact to occur when the athlete lands at the higher speed. Also, because the bands are connected to fixed points on the floor, it is highly likely that the fluctuating lines of force from the bands to the hip will alter the mechanics of the movement. These oblique lines of force contradict the natural line of force of gravity, straight down, causing the athlete to have to fight against an anterior or posterior pull, as well.
In my opinion, the best way to add external resistance to box jumps is by having the athlete wear a weighted vest. As I have discussed already, the weight of the vest should be limited to 10% of the athlete's body weight. The reason I believe the weighted vest to be superior to dumbbells and elastic bands is because the vest does not alter the mechanics of the movement so long as the weight is appropriate for the individual. Because the increased load will slow the speed of the movement, this tool needs to be properly and thoughtfully implemented into a training routine if it is used at all. Also, just as the weight of the body does not change as someone goes through the jumping motion, the weight of the vest will not change, either, unlike elastic bands.
Skipping back to elastic bands real quick, there is something to be said about them if you are wondering why they would be appropriate to add to a back squat or bench press but not to jumping. I will go into more depth on this at a later time, but as a brief overview, bands are implemented to improve the speed with which the bar is moved. While it may seem like this same principle can be applied to jumping, most of the bands used for jumping do not increase tension enough over the short range of motion they have available to be truly effective here. What I mean is, the range of motion used during a standing vertical jump as compared to a back squat is significantly less, so much so that Soviet athletes would train their half squat more than their back squat because of the higher transfer to jumping. The bands are implemented with lifts so once can feel the dramatic difference in tension between the top and the bottom, forcing the athlete to move the bar as fast as possible at the bottom in order to use momentum from that initial push to get to the top. With jumping, though, the tension in the bands between the top and the bottom of the movement is not significant enough to illicit an explosive push from the bottom of the movement due to the limited range of motion used during jumping relative to squatting.
Okay, so maybe that wasn't so quick, but I hope that is somewhat clear. If I were to add bands to my jump training, though, I would try to set them up such that the bands are going straight down between my legs, much like how the weight hangs during a belt squat. This would allow that line of force to be much closer to the line of force of gravity, limiting any anterior/posterior pull. I would still have to consider the faster landings, so I guess that will be something to experiment with in the future.
Charlie Cates, CSCS
Self Made®, Owner
Charlie Cates is a strength and conditioning specialist and the owner of Self Made® (http://selfmadefitness.com/) in Chicago, IL. He has worked with competitive and everyday athletes of all ages and ability levels, from 9-year-old kids to NFL MVP’s. He can be reached via e-mail at charlie@selfmadefitness.com.
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