A common goal among strength coaches is to improve the structure and function of our clients’ skeletal muscle through specific programming that will produce desired adaptations. Whether the adaptation is to be stronger, faster, leaner, or more powerful, skeletal muscle is the main target. Skeletal muscle turns chemical energy into mechanical energy that pulls on our skeletal system to produce movement. We can be lifting tons of kilos in the weight room, running at top speeds, or moving through our daily lives; whatever the movement, there are two main proteins that allow for muscle contraction, called actin and myosin. These proteins slide against each other to cause muscle shortening. Of course, proteins with this much responsibility are going to be highly regulated. Some regulators may make it harder for these proteins to do their job (such as fatigue), and some actually make it easier.
Skeletal muscle myosin light chain kinase or skMLCK for short, is a protein that makes muscle contraction easier through a phenomenon called Post Activation Potentiation or PAP. To keep it simple, when skMLCK attaches onto myosin it causes disorder which makes myosin more likely to attach onto actin and cause muscle contraction. When a maximum voluntary contraction is elicited, skMLCK disorders myosin which increases the rate of force development and force output in the following contractions. Put simply, if we prime our muscles before a sprint for example, we should have an improvement in performance. Rumour has it, Ben Johnson did 3 reps of 600 lbs squats right before his infamous 1988 Olympic 100-meter sprint because of this phenomenon. Yes, I know his medal was later stripped due to a positive drug test but that is besides the point. With this in mind, this rumour contributed to the popularization of PAP in the world of strength and conditioning.
Temperature is another regulator of skeletal muscle. Myosin uses the body’s energy currency, ATP, to attach and detatch from actin to cause contraction. The site on myosin that turns ATP into usable energy is highly influenced by temperature. Increases in muscle temperature, specifically induced by exercise, causes increases in force development and shortening velocity which translates into higher levels of muscular power output. In other words, performing heavy squats for example, causes increases in muscle temperature. If you perform a vertical jump within minutes of performing those squats, your jump height should be higher than if no voluntary exercise (the squats) was done. This phenomenon is called Post Activation Performance Enhancement or PAPE for short. In 1995, a bobsledding team used maximum voluntary contractions to elicit PAP (at the time it was known as PAP but may now be considered PAPE) and they ended up winning the world championships. Maybe these stories involving PAP/PAPE coming up in the strength and condition industry aren’t coincidence after all.
PAP and PAPE are often used interchangeably. However, recently it has been discovered that the timelines and underlying mechanisms of both phenomena do not seem to line up completely but again, this is besides the point. Whether they influence each other or are completely different mechanisms (which is unlikely due to many similarities they share), the bottom line is that a performance enhancement occurs in skeletal muscle following voluntary contractions and in the weight room, there are ways to take advantage of this. A technique called wave loading is a prime example of this. Wave loading groups sets into series (2-3 sets per series and 2-3 series) with each series increasing in intensity. Because of PAP/PAPE, the prior series will prime the muscles to increase force production in the following series. This allows for an increase in load for the same number of reps which can unlock strength, size and power gains depending on how these waves are used.
When using waves for strength gains, we can take a typical strength set/rep scheme such as 6x3 at 85% of your 1RM and turn it into different waves. Wave one may look like 5 reps at 80%, 3 at 85%, 1 at 95%. Now that the muscles are potentiated, we can take advantage of this in wave 2 and increase the load for the same number of reps. So, 5 reps at 85%, 3 at 90% and 1 at 100% as an example. The good thing about waves for strength is that, because the numbers of reps are so low, we can add a third wave if our 1 rep at 100% moved well. Taking advantage of PAP in this way for the third wave may result in a PR!
When using waves for size gains, or hypertrophy training, we can take a typical hypertrophy set/rep scheme such as 6x8 at 72% and again, break it up into waves of increasing loads for the same number of reps. So, we can start 10 reps at 70%, 8 at 73%, and 6 at 78%. For the second load, we can increase the percentages for 10 at 74%, 8 at 78%, and 6 at 83%. Don’t pay too much attention to the arbitrary percentages, just understand that for the second wave, the percentages are higher for the same number of reps because our muscles are primed from the first wave, allowing for higher intensities in the second wave.
When using waves for power gains, things change a little bit. When thinking about power, intensity is important however, so is velocity therefore, the speed at which a lift is performed needs to be considered. You can take a typical power set/rep scheme such as 6x3 at 50% and break it up into waves increasing in load just like we have been talking about. Another option is to keep the loads the same and because of potentiation, be able to move the loads in the following waves faster.
Keep in mind, wave loading is an advanced technique that takes a toll on the central nervous system. It is a technique more suited for someone with a higher training age who understands appropriate rep numbers, loads, and recovery times. It is also important to understand that not every workout you do should include wave loading; these are going to be taxing workouts. With all of that in mind, ride those waves and get ready for those gains!
Blazevich, A. J., & Babault, N. (2019). Post-activation potentiation versus post-activation performance enhancement in humans: Historical perspective, underlying mechanisms, and current issues. Frontiers in Physiology, 10. https://doi.org/10.3389/fphys.2019.01359
Bret Contreras. (2016, September 19). Post-activation potentiation: Theory and application. Bret Contreras. Retrieved March 21, 2023, from https://bretcontreras.com/post-activation-potentiation-theory-and-application/