By: Danny Raimondi

Most coaches are aware of the theory behind post-activation potentiation, also known as post tetanic potentiation.  I first read about this in article by Charles Poliquin in which he discusses the “1-6 method”. Intuitively, the method makes sense, and if you ever decide to try it out, it probably will work. To perform the method, for example, take a heavy squat, perform 1 repetition, drop the load, and perform 6 repetitions.  The next series take a heavier single and a heavier set of 6. Repeat this process usually for 3-4 series. The biological rationale behind the improvements you’ll most assuredly gain on the subsequent set of 6 has to do, in theory, with the nervous system.

Potentiation doesn’t end there, however. Research has also examined the effects of strength training exercises on subsequent low load, high velocity activities. Squat a heavy weight, go run a sprint, and see if there is any improvement. Granted, I’m grossly oversimplifying the process (I’m not accounting right now for rest times, percentages of certain lifts, training age, etc…), but we’ll leave that for later.

In a recent study by Bullock and Comfort (2011), the authors examined the effects of 2, 4, or 6 depth jumps on squatting performance.  Using a randomized control study, 14 males tested their maximal squat 5 times with at least 3 days of rest in between.  The subjects performed depth jumps from a height of approximately 12 inches followed by a maximal effort squat to 90 degrees of knee.

The authors found that performing  either 2,4, or 6 repetitions of the depth jump approximately 4 minutes prior to a maximal effort squat will yield significant (p<0.001) results. While the researchers note that there was no significant inter-repetition difference (i.e. performing 2, 4 or 6 didn’t yield any significant results), there was a greater potentiation effect trend using 6 depth jumps among stronger (squat greater than or equal to 2x bodyweight) athletes. It ultimately depends, as the authors concluded, on the rest between exercises and the volume of jumps with respect to the athlete’s training level.

Now for the limitations of this study, because there’s always going to be some confounding variables. The authors used a fairly small population (14 subjects with a moderate amount of training experience).  Consider, however, the nature of research and funding in exercise science. While the population seems small, it’s not uncommon to see small sample sizes when money is hard to come by. Obviously the question of training experience also comes into play. Some athletes were demonstrably stronger than others, and may have greater neural ability (i.e. rate coding, motor synchronization, etc…) during the squat and depth jump movements. These same individuals may be more likely to respond to higher volumes, whereas lesser trained individuals would really respond to any extra stimulus.

One of the major limitations of the study, I believe, was the manner in which depth jumps were performed. The researchers used a 12 inch box, which, albeit, isn’t very high. For the training experience of this group, however, it may have been sufficient. The real kicker in this study is that the authors, to control for arm swing, had the athletes perform the jumps with their hands on the hips. This greatly reduces jump height and technique. Ground contact time, force production, and jump height are all compromised when removing the hands from the equation.  One could make a case that the manner in which the researchers tested the squats is also a limitation, but I think that’s secondary to the performance of jumps.

So what’s the take home message for physical preparation coaches? Well, the research is by no means definitive. There are still many confounding variables that can explain why the athletes did better.  As a coach you obviously must account for an athlete’s ability and the context in which you’re applying the stress ( i.e. what time of the year, what outcomes are you hoping to achieve, etc…).  You might consider adding low load, high velocity movements, such as drop squat jumps, in the warm up prior to heavy squat days in order to potentiate the latter.  One must simply remember that more intense means, such as high depth jumps performed for relatively high volumes (≈ 10 or more jumps in a series) probably require priority in a workout and may not be best when paired with squats.

As the late Yuri Verkhoshansky said, depth jumps are one of the final stages in the process of developing explosive power.  Or, to paraphrase a teacher of mine here at the U, it’s like showing an athlete all your cards. It might be better to save depth jumps and more intensive means for those who will respond better when the time comes. If you “waste” the movement on a low level athlete, the adaptation that could have been achieved might be diminished.  Ultimately, as this and many other studies have supported, potentiation seems to be an effective method of improving various abilities (explosive power, maximal strength, decreased ground reaction time, etc…).  Anecdotally, and this can be just as important as the formal research, many people have touted the benefits of coupling exercises in a ‘complex’ fashion.  Before running out and doing depth jumps every squat day now, though, be sure that as a coach you understand what adaptation you’re looking to achieve, when you want to achieve it, and who you’re applying it to.

Bullock, N. & Comfort, P. (2011).  An investigation into the acute effects of depth jumps on maximal strength performance. Journal of Strength and Conditioning Research, 25(11), 3137-3141. DOI: 10.1519/JSC.0b013e318212e224.

In today’s post 2012 Seminar presenter Cal Dietz brings the great debate of single leg vs double leg lower body exercises to the forefront.  To squat or not to squat has been a polarizing question of late.  Coach Dietz gives his take on both tools, how he utilized both and his reasoning behind it.

In the past several years many controversial articles have been written about whether double leg training is superior to single leg training and even if bilateral exercises (i.e. heavy squats or leg presses) are necessary to achieve the same results. Keep in mind that results are relative to your particular sport that you are training for. Some sports don’t need very intensive measures to get these types of results. For example, I find that golf is a sport that if an athlete seems to be strong enough, he or she can reach their intended goals by doing mainly single leg work and those types of exercises to get the desired results. Please keep in mind that the following are my, as well as many other unnamed strength coaches, opinions.

So, in regards to the single vs. double leg debate, my thoughts immediately jump to getting results in testing. The testing results are not necessarily getting strong in the back squat. These are based on 10’s, 20’s, pro agility, vertical jump, and mainly the explosive sports and sports tests. In review of my records over the last decade and different transitions that have happened for athletes from the double leg training to the single leg training, I researched and thought about as many instances as possible within our own system of training and this is what I found: I was unable to find any records, testing results, or performance results based upon an athlete that had trained in our system over one year and as much as three years with the double leg back squat or front squat methods that were able to reproduce results in testing and/or performance based sports such as track and field.

I will give one example and one example only. I had a very athletic female athlete who I considered late to mature physically and was biomechanically gifted strength wise to start when she walked into the weight room. Her first test was a pro agility. These numbers were a 4.91, no hand touch, pro agility. She simply ran a pro agility by getting her foot beyond the line. After 15-16 months of training, including in season training protocols, she was able to run a 4.32 in the pro agility without a hand touch. After a couple of years of severe wrist and shoulder injuries, we were unable to load the body with a double leg approach. The best results she could get in a pro agility after an entire summer of training extremely hard was a 4.65 pro agility.

This is an obvious and simple example of how I am unable to reproduce efforts when single leg work is the main focus of a program. Trust me, I believe in single leg work, I use it in many of my programming methods, but I truly believe and have seen that I cannot get the results with these particular methods by only using single leg work. Here is something to we must think of when addressing single vs. double legwork. It would almost be impossible to do, but if an Olympic lifting athlete removed all double legwork except in the clean and snatch movements, would they be able to hit maximal effort lifts? I believe we know the answer to this without answering it. So then we get back to addressing why particular double leg exercises produce superior results?

I truly believe the main reason is a systemic effect over the whole body with a very intense response to heavy loads( instability via single leg lifts decrease motor unit recruitment). Essentially, in my system, back squats rarely go over 10 seconds in duration with a complete set and it is a very intense 3-10 seconds of squatting. It is more efficient to work the alactic system using bilateral lifts; when doing a single leg exercise, most people will raise the repetitions of it thereby stressing certain energy systems more than others due to the fact that both legs need to be exercised. For my system, which deals with many alactic and alactic-aerobic sports, I have found that single leg lifts cannot compare in intensity as their double leg counterparts. Please keep in mind, however, that one way to offset the exercise becoming so anaerobic-lactic would be to do the left leg, rest 30-40 seconds, and do the right leg. This will keep the emphasis alactic, though still the intensity will be reduced due to the inherent loading limitations of single leg exercised.

I have various methods of programming for the back squat and single leg work. Some of my programs have only squatting with minimal single legwork, whereas other programs have minimal back squatting and mainly with single legwork. Some of my methods use only single leg work. Some of the most beneficial programs I truly believe are the beginner variations where we’ll back squat and do single leg work initially, then transfer to single leg work based upon loads and speed of the movement. I truly believe that one can pull back squats 4-6 weeks out of the main competition and time of performance and still keep relative strength to the sports performance extremely high. Even if they lose strength in the squatting motor skill, it does not mean they lose performance; it can actually mean the opposite if you are doing the right exercises in the latter part of the program to peak for performance.