Adding Resistance to Sport-Specific Skills

Image courtesy of http://www.ebay.com/

“It was correctly noted that heavier implements can have a positive influence on an increase in physical abilities and a negative one on technical mastery.”

--Anatoliy P. Bondarchuk, Transfer of Training in Sports

One of the biggest problems I see in sports performance today is the addition of external resistance to technical skills that are vital to an athlete’s success in his or her sport. Clear examples of this can be seen in the addition of doughnuts to a baseball player’s bat while he is in the on-deck circle or golfers swinging with heavier clubs than they are accustomed to while warming up. In the video below, you can see the danger of this from a performance perspective, courtesy of Sports Science.

While the bat and the club are great examples, I would also like to consider two movements that are found in almost every sport: running (or sprinting) and jumping.

Yes, both sprinting and jumping are skills and the performance of each movement can be improved by simply improving the technique of each respective movement. The problem from here on out is that for me to give actual recommendations regarding what you should do as an athlete, coach, or trainer would be both ignorant and futile. Instead, I would like to discuss what I see as the pros and cons of some of the more mainstream forms of adding resistance to the sprint and the jump.

Weighted Vest

Image courtesy of http://www.canterburysports.co.nz/

The weighted vest is one of the most common tools used when someone wants to add resistance to their vertical jump training. Rarely have I seen a weighted vest used as a tool to improve sprint performance, although it may be worn for conditioning, which is distinctly different due to the intended adaptation that is being trained for.

One problem I see from a technical standpoint is that most weighted vests are too heavy for the individual using them if technique is not to diminish. According to Bondarchuk, “The portion of maximum intensity training loads used in the process of mastering technique should be about 10%.”[1]

Now, as a disclaimer so as not to completely take the quote out of context, Bondarchuk wrote this book while studying track and field athletes and, in particular, this quote was referring to throwers using heavier implements. For the sake of this discussion, though, I know I have seen research elsewhere of the “10% rule”, but am failing to find said research to quote at this moment. Regardless, it is an interesting point to consider.

So, in terms of using a weighted vest for vertical jump training, what does this mean? Well, because you are just simply adding weight to the body it is fairly easy to calculate. Much like the increasing the weight of the implements by 10% in Bondarchuk’s research, it would seem that if you were to use a weighted vest that is less than or equal to 10% of your body weight the mechanics of jumping would not be altered, or at least would have the greatest opportunity to not be altered.

To dive into why this is would be to go outside of the scope of this article, so for now I will leave it at the specific sequence of muscular contraction that takes place under normal conditions of jumping with only body weight is altered when external resistance is added. According to Bondarchuk, this alteration is significant enough with resistances over 10% to deviate the mechanics of the movement from what would be considered optimal.

Resistance Bands and Tubes (Accommodating Resistance)

Image courtesy of http://www.diamondfitnesssystems.com/Page_Vertimax.htm

A resistance band, as I am defining them here, is essentially a big rubber band that provides increased resistance the farther you stretch it. Bands do not have a starting or stopping point and instead are basically a circle of rubber while a tube has a distinct stopping and starting point and is more of an elongated cylinder. From this point forward, when I refer to a band or tube, I am speaking to characteristics of both.

The accommodating resistance is a unique aspect to the resistance band when compared to the weighted vest or weights in general. Another variable of the resistance band that can be manipulated to your advantage is that you can easily create a line of force that is independent of gravity. You always have the force gravity pulling straight down, but with the resistance band you can have another force pulling in another direction, whether that be straight back (posterior), as is most commonly seen with sprinting, or at an inferior/oblique angle, among an infinite amount of other possibilities. An example of an inferior/oblique line of force would be connecting bands to a belt worn around the hips and then to fixed points on the ground lateral to the body, much like what can be seen when using a VertiMax Jump Trainer.

The VertiMax V6

When you have two or more lines of force acting on a single point of application, you get something called a resultant. With a resultant, you are taking the relative pull of all the lines of force and creating one new line of force that is directionally somewhere in between the original lines of force. Take the VertiMax, for example. You have gravity pulling straight down and then you have tubes that are strapped to the knees, hips, and wrists pulling towards the ground at an inferior/lateral angle. Each one of these points where the tubes are strapped is going to have a separate resultant. Generally speaking, each resultant will be found somewhere between the medial aspect of the tube and the lateral side of the body, with the angle of the resultant unique to each point of application (where the tube is strapped). Not only that, but the angle of each resultant will change as you perform any and every movement due to the changing limb position and, in turn, the point of application relative to gravity and the tension of the tube.

Okay, so there is a lot of technical verbiage in there. Breaking it down, I am basically saying that by adding to a movement a band or tube that is not specific to each joint and the direction of the movement, you are now adding a resistance that is alien to the movement itself. Subsequently, the muscular recruitment must be altered in order to keep the mechanics the same as the original movement. If it isn’t, then mechanically you will not be able to produce the same movement because the forces that you have to overcome are different.

Putting this all together, I cannot sit here and tell you if it makes sense for you to add resistance to these movements that you use in sport. But, I can say that if you don’t understand how to properly apply forces to the body you are shooting in the dark when it comes to whether or not you will be able to create your intended adaptation. Understand that by adding something in, such as another form of resistance, you are likely giving something up in the form of technical competency from a neuromuscular and/or mechanical perspective. I am not saying that training with these tools will not help you improve the gross performance of the movement or that there isn’t a place for them in a training program, but rather that you may be sacrificing something along the way. Understand the individual you are working with, understand the risk to reward ratio of what you do, and choose your methods and tools accordingly.

Get big or die tryin’.

Charlie Cates, CSCS

Self Made_®, Owner and Founder

Charlie Cates is a strength and conditioning specialist and the owner and founder 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.

This article may be reproduced with biographical information intact.

---

[1] Bondarchuk, Anatoliy P. Transfer of Training in Sports. p. 178

How to Add External Resistance to Box Jumps

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.

Get big or die tryin'.

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.

This article may be reproduced with biographical information intact.

How Much External Resistance To Add To Box Jumps?

Earlier in the month I posted and article from DieselCrew.com on how to increase your vertical jump. One of the suggestions given by the author was to perform weighted box jumps, with the corresponding video depicting someone performing box jumps while wearing a weighted vest. But does wearing a weight vest when performing box jumps make sense, and how heavy should the weight vest be?

First of all, jumping is a skill, just like sprinting, throwing, catching, and shooting are skills, and all of these can be improved with practice of the skill. The other takeaway from this is that the movement and muscle firing pattern is very technical and it can be altered if too great of an external load is applied. This is described by Yuri Verkhoshansky in his book Supertraining, "While simulation of a sporting movement with small added resistance over the full range of movement or with larger resistance over a restricted part of the movement range may be appropriate at certain stages of training, simulation of any movement with significant resistance is inadvisable since it can confuse the neuromuscular programs which determine the specificity of the above factors." (Verkhoshansky, p. 27). So the question then becomes, how much of an external load is appropriate?

From the literature I've read, the number I've continually come across regarding skill development is 10%. Anatoliy P. Bondarchuk touches on this subject is his book Transfer of Training in Sports, "The greatest amounts of correlational interrelationships were most frequently found in cases where the deviations between the lighter and heavier implement weights was insignificant in relation to the competitive—from 10%..." (Bondarchuk, p. 98). In terms of jumping, I would not use a vest that is heavier than 10% of my body weight. As I said above, this is because adding a load greater than this has been shown to alter the technique of the movement, in turn altering the movement itself.

So, if you are going to add a weight vest into your box jump routine, keep it to 10% of your body weight. Something also to take away from this is that after you have performed the movement with the external resistance, make sure your last reps are at your normal body weight so your neuromuscular system further cements that movement into its firing pattern.

In my next post on this subject, I will discuss the difference between using a weight vest and other means of external resistance for jump training.

Get big or die tryin'.

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.

This article may be reproduced with biographical information intact