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Why Do Reps Even Matter?

Written by: Kevin Cann

 

This is a question I have been asking myself a bit lately.  This article is just going to be some thoughts, an inside to my thinking process if you will.

 

My guess is that this started around the 1970s when there was this obsession about the Russian’s training secrets.  This was the birth of our periodization models here in America.  These periodization models broke training up into specific phases.

 

These phases tend to be a preparatory phase, a competitive phase, and a transition phase.  The preparatory phase recommendations are for lots of non-specific high repetition work.  In some sources they recommend around 12 to 20 reps.  The competition cycle would be more specific work and between 2 to 8 reps, and the transition phase would be time off after competition.  Perhaps the lifter does some different activities here.

 

Over time this got adapted more.  There became hypertrophy, strength, and power phases.  Even those these phases had different names it was the same exact model repackaged in a different way.

 

So, back to my original question, “Why do reps matter?”  The idea between higher rep sets is to increase the size of the muscle within the lifter.  Theoretically a larger muscle has the ability to lift more weight.  When we look into the literature this narrative just does not hold true.

 

Muscle mass can be obtained from various loading schemes.  However, strength tends to be higher in the groups lifting heavier. This makes sense as the heavier loads are more specific to the sport.

 

There is some correlation to larger muscles moving more weight, and if you are a coach or lifter that performs high rep sets for this, and you enjoy doing them, by all means keep doing it.  I am just not convinced by the available evidence that this is worth the time, which is also a constraint on lifters, in the gym.  There is a Boston’s Strongcast episode with researcher, Dr. Loenneke, that discusses these topics in further details.

 

If we analyze the sport of powerlifting this may help to give us our answers.  It is a sport where the lifter takes 3 attempts of a single repetition of the squat, bench press, and deadlift.  Each attempt gets heavier from the first attempt to the third attempt of each lift.

 

The third attempt should be a maximal lift for the lifter.  A maximal lift may take anywhere from a couple seconds, and I have seen upwards of 11 seconds.  Looking at this information, I would say that reps matter up to the maximal amount of time the lifter will be lifting a maximal attempt for.  For the information I have, 11 seconds (that was on a deadlift, squat was 8 seconds, and bench was a little less than squat).

 

This is the equivalent to a set of 3 repetitions.  A hard set of 3 reps is probably taking a bit longer as well.  The research has shown that to get stronger, you need to lift larger loads.  Well, what is a larger load?  The research suggests that loads greater than 85% of 1RM are ideal.

 

Research also suggests that the internal loads, not the external loads, are the drivers of physiological adaptation.  The most common way to measure internal loads is with RPE.  From practical experience I have found that an RPE 8+ is pretty sufficient for strength increases.

 

The closer to maximal we get the better here.  My guess is it is due to psychological factors.  The heavier weights peak arousal from the lifter.  This forces them to handle their emotions.  As Keith Davids says, “Training should have consequences.”  There are a large number of lifters that undershoot this RPE, so I make our hard sets a range from 8.5 to 9.5.  I would rather them overshoot here than undershoot because of the number of sets we are performing.  Usually starting out at 1 to 2.

 

The dogmatic argument to this is that you can’t lift heavy every day like that because of overtraining. The idea of overtraining comes from Hans Selye who shocked rats in the 1930s.  This literally has nothing to do with lifters taking a handful of hard sets 3-4 days per week.

 

Research struggles to induce overtraining symptoms from intensity alone, and they do things that are far removed and much crazier than the real world would.  There needs to be an endurance component to this.  Higher volume programs have an endurance component, perhaps this is where that fear came from?  I do not know.

 

The argument then is always “But volume matters!  You’re dumb! (insert appropriate emoji here).”  Not all volume is created equal.  Seems there needs to be a higher intensity to it, and a duration of no more than about 11 seconds.

 

We typically start at 5 repetitions.  My argument is that this gives the lifter greater exposures to new variations to figure it out.  It is hard to load it up for a heavier triple right away.  When I go back and analyze the 5s, I saw some interesting things.

 

Reps 1 and 2 are definitely not intense enough to be included in the volume that matters. Reps 4 and 5 were mostly effective reps, and rep 3 was sometimes effective.  Keep in mind the majority of the sets are taken at around an RPE 9.5. The days of the 8.5s is usually when the lifter is feeling a little tired and banged up.  This puts that 3rdrep around an 8.

 

On sets of 3 the first rep is probably outside of the range of intensity to be counted as an effective rep. However, the 3rdrep is important for the timing component of the sport.  We need to learn how to lift for upwards of 11 seconds.

 

In terms of volume, we need to define how we use volume.  Most use total tonnage and average intensity.  I use “number of hard sets.”  I don’t care whether it was a set of 5 or a set of 1 it gets the same score, 1 volume unit.  The reason for that is with the effective reps for one.

 

Also, there is a lot of uncertainty with using volume to predict progress.  Tetlock showed in a long running study that experts with more information tended to make worse predictions.  I choose to keep it simple and to give me an idea about how hard the lifter is working.  If progress seems to be stalling, we can add more hard sets.  This is pretty simple.

 

I think reps are important for practice.  However, we want them to be more deliberate for the sport that we are competing in. A set of 10 at 70% is not practice for powerlifting in my opinion.  The weight is too light to create technique issues, it is too light to create an emotional response, it lasts longer than 11 seconds, and its reasoning is based off of Russian folklore from the 1970s and before.

 

I view volume as measuring practice time within the sport itself.  Wouldn’t I want to know how many sets the lifter is performing that is actually going to yield benefits?  Wouldn’t this help me see the training process better and give me the necessary information to make the decisions for that lifter to increase progress?  I think so.  Of course, we can’t forget about manipulating other factors such as exercise selection.  That is usually my go to.  You will be surprised at how often adding more volume is not the answer.

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Predicting Earthquakes and Powerlifting

Written by Kevin Cann

 

I had stumbled upon Per Bak’s book “How Nature Works.”  Bak is a physicist that developed a theory of complexity known as self-organization criticality (SOC).  Basically, he theorizes that all complex events reach a critical state.

 

Once this critical state is reached there will be what is known as a phase transition.  There will be what is known as avalanches of all sizes. The term avalanche comes from Bak’s earlier experiments using sandpiles.

 

Bak and colleagues continues to add grains of sand, one at a time, to a pile of sand grains.  Once the pile reached a critical state, where it could reach greater heights, it would be considered to be in a critical state. This point in time is known as the “edge of chaos.”

 

Bak and colleagues would continue to add individual sand grains and witness these avalanches. Sometimes the avalanches would include just a few grains, other times it would reshape the whole pile in much larger avalanches.

 

What they noticed was that the avalanche sizes were very random and completely unpredictable, but they followed what is known as the power-law.  The most famous example of the power law is the Richter scale used for earthquakes.

 

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The power-law states that large events are no different than smaller ones, they just happen at lower frequencies.  An earthquake of 5 on the Richter scale occurs more frequently than one at 6, which occurs more frequently than one at 7, and so on.

 

From this scale one might set the probability of a 7 rated earthquake in a particular area as occurring 1 time in every 35 years.  This does not mean that it actually happens every 35 years and we can predict this with regularity.  Currently we have no ways to predict any earthquakes.

 

This area could have 2 catastrophic events in back to back years, and these 2 events could be the only catastrophic events in a 100-year period.  Perhaps the 3rdis the following year.  The long-term statistics show that it does in fact occur 1 time in every 35 years, we just have no idea when it will happen.

 

We can’t predict the things in which we do not understand.  We do not understand what causes the fault lines to build up energy, leading to a shift in tectonic plates, and causing an earthquake.

 

Science attempts to reduce the studies to these fault lines.  Chances are everything is connected.  Landslides causing shifts in landscapes, volcanic activity, atmospheric changes, ocean temperatures, and so on are probably all variables in play to understanding earthquakes.  Each individual piece is extremely complex.

 

When there is an earthquake, we see a shift in the landscape that changes the flow of rivers.  This alters the species distribution in an area and also paves the way for the rise of new species.  Earthquakes are a way that the earth self-organizes into various states.  At times the earth is in stasis, frozen where it is, and at times it is in a critical state where there will be a phase transition.  Earthquakes are adding a grain of sand to earth’s sandpile.

 

Bak and colleagues later created a computer program to attempt to see if population growth and mass extinctions followed this same power law.  This program included 1,000 species that were represented by variables and assigned a random number.

 

There was a food chain to the immediate right and left of each species.  The researchers would run the program until the environment reached a state of stasis.  This just means it was frozen where it was at.  No further changes would occur.  Oftentimes this would happen without reaching a critical state.

 

Once the environment was frozen, the researchers would remove the least fit species and replace it with a new one.  The experiment would run again.  Eventually there would be a critical state and the researchers would see chaotic behavior as well as mass extinctions.

 

Biology is extremely complex.  No one really attempts to answer the question of “Where did life come from?”  This question is perhaps the most important question to answer, but also one without even a good starting point.

 

Training is just like the experiments on mass extinction.  The lifter starts somewhere.  Instead of species we have all the feedback loops that the brain analyzes such as energy, mood, core temperature, expectations, past experiences, beliefs, and so on.

 

The lifter runs that program and reaches a frozen state, perhaps hitting a small PR.  We change things up and run it again.  Every so often instead of reaching a frozen state we reach a state of criticality.  We keep training and all of a sudden, we hit a large PR.

 

I would theorize that these strength increases would follow a power-law.  Small PRs, or avalanches, are more frequent than larger ones.  There would be the same line as seen on the Richter scale.

 

According to the power-law the large PRs are no different than the smaller ones.  Just random occurrences that occur at different probabilities.  As coaches we attempt to find trends in these scenarios.

 

For example, high volume leads to a large PR so I must respond better to higher volumes.  As humans we love to trick ourselves into seeing trends in events we do not fully understand.  Humans do this all of the time.  An example is the stock market and also the weather.

 

We are good at forecasting probabilities with the weather because we have a solid understanding on how the particles work in the atmosphere.  Biology is far more complex than the weather.  Biology is more like earthquakes.  We just really have no idea.

 

With that said, the research on mass extinctions tells us quite a bit.  We start somewhere and just watch.  We measure objective outcomes and when the lifter seems to be in a frozen state, we change it up and repeat the process all over again.

 

We have zero predictive power in knowing how this will play out each time.  Large PRS are no different than small ones.  They are not special.  Thinking that they are can get the coach into a bit of trouble.

 

Just keep training and observing the lifter’s performance.  When it seems to stall, change something up.  This may work, it may not.  If it does it is not because you were right, and if it doesn’t it was not because you were wrong, it is just the way of the universe.

 

 

 

 

Training Needs to Have Consequences

Written by Kevin Cann

 

A big part of my job is handling the emotions of the lifters.  We do not just follow a simple program.  The lifters are responsible for a large amount of their training.  They are required to pick the weights for their top sets each day.  These weights should be at or near maximal.  We put an RPE 8.5-9.5 on it, but I would prefer them to overshoot than undershoot.

 

Training at these intensities on a daily basis can be pretty tough, both physically and mentally.  As all of us know, the training process is non-linear.  We do not just come into the gym and hit PRs every day.

 

There are days where we will fail to get to our top sets, days where weights feel much harder, and this can go on for a period of time.  The human is an open complex system, it is not a machine.

 

The brain analyzes an enormous amount of information from mood, energy levels, core temperature, hydration, as well as expectations, beliefs, past experiences, and makes a decision on perceived effort based off of this information.

 

The coach needs to juggle this uncertainty with the lifters.  There is a difference between risk and uncertainty when looking at predictive processes.  Most coaches assume there is a risk of, let us say increased fatigue leading to a drop in performance.  They may add in a lighter day to help to dissipate some this fatigue.

 

This is assuming quite a bit of information.  Uncertainty on the other hand, according to Nate Silver, is a risk that is hard to measure. We cannot measure fatigue.  Even if we could we do not understand how it actually affects performance.

 

I am not saying that fatigue does not exist, I am saying that the human body is capable of handling its shit. We choose to stop an exercise long before we die.  These feedback loops are in place for a reason and it is a remarkable thing.

 

The brain of the individual can measure the unmeasurable and make decisions that are best for that person at that time.  One way it does this is by increasing perceived effort.  This will make lighter weights feel heavier and almost always leads to less sets being completed.  There is volume control.  The opposite happens as well.

 

In ecological psychology there are two different paths that can alter the individual’s behavior. There is a global and local part to the system.  The local part is the individual and the global part is the coach.

 

If the coach tells a lifter that they are tired and that is why they are seeing a drop in performance and they should perform a lighter day, they are projecting their beliefs onto the lifter.  They are assuming they understand the variables and can make a calculated risk. This is what data driven programs do. They attempt to find trends.  In this case powering through may be a better option.

 

College professor of cognitive sciences at MIT, Tomaso Poggio stated, “These evolutionary instincts sometimes lead us to see patterns when there are none there.  Finding patterns in random noise.”

 

In this day and age of overwhelming information, we are no smarter now than we were before.  Just like with volume, more information is not necessarily better.  Instead we decide to find those studies and explanations that confirm our bias.  We all do this, even me.

 

This is why philosophy is so important.  It makes you think about the world in very different ways.  It poses open ended questions without answers and teaches you how to embrace uncertainty instead of taking calculated risks that ignore bias and uncertainty.

 

In order to take a calculated risk we need to understand all of the variables involved.  Something like poker has a finite number of possibilities.  Measuring human existence is far more complex than poker.

 

When the Patriots were down 28-3 in the Super Bowl against the Falcons close to the end of the 3rdquarter, the probability of them winning was less than 1%.  We all saw that play out much differently. Scenarios like this happen all of the time.  We are terrible at predicting things.

 

The coach needs to understand this and let these situations play out.  Their language and decisions need to embrace the uncertainty. Attempting to measure these things may be right sometimes, but it will be wrong more often than the coach would like.

 

I follow a dynamic systems theory approach to training.  There are 3 constraints the coach needs to be aware of; the individual, the environment, and the task.  All 3 of these will pull training one way or the other whether we like it or not.

 

The individual is not just bones and muscles.  We are very good at measuring physical components of the individual’s training. However, we are very poor at measuring the psychological pieces that come with training.  Many use RPE in training and forget that it is perceived effort.  The brain can be trained just like the muscles to perceive things differently.

 

In order to do this we need to train with consequences.  The weight on the bar has to be enough to create an emotional response from the lifter. The lifter then needs to learn how to deal with this emotional response.

 

I was listening to a podcast with Keith Davids (wrote the book, literally, on a constraints-led approach) and he was talking about Parcor and how this is good training for athletes. He gave an example of an athlete approaching a wall and stopping 3 times before he finally performed the task.

 

He spoke about the emotional stress this was causing on the athlete and how the athlete had to learn to deal with it.  On the field, that wall could be a linebacker trying to tackle him.  There is a lot of carryover here.

 

This really resonated with me because the PPS lifters approach that wall every day, but we perceive it differently each day.  That wall is the top set of near maximal weights.  Sometimes the jump looks further, or the fall looks further down, our legs may be tired, it may be hotter temperatures outside, we may not be feeling into it on this current day.  Maybe we missed this same jump a few times before.

 

All of these factors will affect the outcome.  Sometimes the outcome will not be the one that we want.  This will increase levels of frustration.  When these frustrations arise the lifter needs to be able to separate emotions from decision making and figure out what to do next to get the most out of this training day.  Pouting and temper tantrums will not help to make them stronger.

 

This can be very tough on the coach.  It is always easier to just give into the lifter and just give them lighter weights for multiple sets to help build confidence.  I get this argument, but I disagree with it.  This does not teach the lifter how to deal with the inevitable frustrations of competitive athletics.  Powerlifting is competitive athletics.  Instead it is the coach having them self-organize globally, based off of the coach’s beliefs, and not locally.  This is not easy on the coach, but the coach needs to trust in the individual to find a way. The coach can offer guidance on how to deal with these frustrations.  Sometimes this may be pulling back a bit from training, but more often than not it is keeping frustration high to force adaptation to it. We do not only compete when we feel good.

 

The internal load is moat important for building physical strength within the lifts.  As long as we keep effort high, we are getting a training stimulus.  We alter the task to punish inefficiencies and promote a recalibration to more efficient techniques of the lifts.  We also set up the training to elicit a continues emotional response.

 

Building an emotionally strong lifter is important for them to be the best lifter that they can possibly be.  Elite athletes all share this in common in other sports.  They have this sense of irrational confidence mixed with mental resiliency to be able to push themselves beyond typical levels of perceived effort.  This is what we are learning to do in the gym.

 

Doing this allows us to practice less to get a strong training stimulus.  We can spend less time in the gym with greater outcomes. There are greater life lessons to be learned here as well.  It gives each lifter tools to deal with frustration that will be inevitable in all aspects of life.

 

This requires the coach to educate the lifters as well.  They need to understand that they are not losing strength because there is a down day in the gym.  You do not get weaker by training hard.  The coach needs to teach the lifter about expectations, beliefs, and past experiences and help to guide the process by violating preconceived expectations and building new experiences.

 

The lifter can allow the frustration to spiral and lead to many bad training days and a plateau in strength.  However, if they learn to handle this frustration with high training skill, they will be able to push progress and hopefully avoid long standing plateaus.  Unfortunately, plateaus will still be inevitable, but if they understand that, accept it, and know it will turn around with high effort and good decision making it will lead to a much longer and enjoyable career. We learn this by training with consequences and emotions.

Attractors, Distractors, and Cognitive Penetrability

Written by Kevin Cann

 

When I have explained a Dynamic Systems Theory (DST), I have mentioned the term attractors.  An attractor in a dynamic system is actually a mathematical model where the system always seems to end up at this numerical point regardless of the initial conditions.

 

When we look at skill acquisition an attractor state is the chosen technique from an athlete under competition requirements.  For example, when the squat gets heavy the lifter pitches forward out of the hole.

 

We could perform a bunch of lighter weight squats that look good, but this often does not change the attractor state as it does not take into account the emotions of the lifter. Emotions come into the lift when it gets heavy.  I think what we often see is when an athlete becomes nervous, they speed things up in their mind and we see a loss of position.

 

Emotions are a distractor to the task at hand and they alter how we perform these tasks.  To further explain, we need to understand how attention works.  Our brain is sifting through a ridiculous amount of information.

 

Think of everything in your visual field when you look somewhere.  If we lacked attention, we would not have spatial awareness and we would not be able to combine light into colors and objects.  It would be impossible for us to perceive the world.

 

Our brain uses attention to focus on specific objects that give our world context.  Our brain predicts what we will see before we even turn our heads to look.  We will focus (attention) on the objects that we expect to see.  These objects will give our world context in spatial and object recognition.

 

Distractors would be anything that pulls our attention away.  Perhaps in the scenario above we hear a loud crash behind us.  This would get us to turn our head quickly as we may be predicting there was an accident.  Imagine if we were attempting to throw a ball at a target.

 

We see the target and everything around it kind of fades out of view.  Then we hear that same crash.  Our attention has gone from the target and the task at hand to seeing if there was an accident.  Or maybe we are driving along, and a person darts out in front of the car and we slam on our breaks.

 

This happens with training. Our system cannot distinguish between our targets and distractors, no matter how involved in a task we are. This allows the system to remain responsive to any unexpected dangers.

 

As a coach we can tell a lifter to slow down and control the squat as much as we want, but it most likely will not work until we alter the task constraints.  The lifter is too open to the signal of the distractors, which pull the lifter into the desired attractor state of a squat with the pitching forward.

 

In order to destabilize this attractor state the lifter needs to learn to deal with the distractors. This is why the individual is a constraint we need to take into consideration.  Their emotions, beliefs, perceptions, and past experiences are all tied to this attractor state.

 

The more a lifter experiences emotional stress while lifting, the less threat that is perceived with that distractor.  This allows greater attention to be given to the actual task.  If the task is unable to be completed with that pitching forward pattern, and only can be completed with an upright torso, we can begin to destabilize the old attractor state into a new one.

 

Get a group cheering you on and we have all 3 constraints; the individual, the environment, and the task covered.  This is basically using multiple differential equations in the real world.  Math is cool, especially complex math.  Just focusing on the mechanical stress is applying a linear regression to these equations and will yield far less results.

 

This is the theory of cognitive penetrability of perception.  Basically, our psychological factors influence our perceptual experiences. We perceive the world, and we perceive movement before it occurs.  This is where I believe the majority of our attention (see what I did there?) should be focused.

 

There is this old dogma, that breakdowns in the lifts are caused by individual weak muscle groups. This believes that the body performs a task as a sum of all of the muscles added together.  I just do not see how this can actually be true.

 

I think this became a dogma because we can measure muscle contraction in the lab.  We cannot measure psychological factors or perception in the same way.  The brain controls the coordination of the muscles.  This is why we can’t just do accessories and the big 3 go up.

 

The argument is that the accessories in combination with the big 3 work.  This may work in some cases by altering expectations.  If the lifter expects it to work, believes it will work, and has done exercises in combination with the big 3 before with success, it can work.  However, I will argue that it works for psychological factors and not mechanical ones.

 

Similar hypertrophy can be seen across a wide range of loads, even as low as 20% of 1RM, as long as we are training at or near maximal.  I do not buy the theoretical argument that a bigger muscle has greater capacity to contract.

 

I believe that a stronger mind gives that muscle a greater ability to contract.  If I train at greater than 85% of 1RM at or near failure, and someone trains at 20% at or near failure, our muscle increases will be similar, but strength will not.  The million-dollar question is “why?”

 

This doesn’t mean that you do some Jedi mind tricks and your total goes up, although it helps.  You train at heavier weights and your perceived efforts change over time because you are pushing them and challenging them. If a lift feels like an RPE 9, but everyone says to go up, and you go up and hit it you are altering your perceived effort.  Your brain needs to update its priors on what an RPE 9 is.

 

I run variations in a pretty linear fashion.  I think each week this helps the perceptions of the lifter.  If I take 400lbs for 5, I know I can take 420lbs for 4, and 435lbs for 3, and so on.  Chances are the lifter was capable of hitting that new 1RM weeks earlier, but their mind was not ready to do it.  It is not like we get to a single with a 20lb PR and that just happened from tapering volume and supercompensation.  It got the mind ready to handle the new weights.

 

We hit these PRs often with much better technique.  My theory is that the emotional stress was no longer a distractor.  That distractor has changed to much higher weights now.  With less fear and less nerves, the lifter is able to put more attention to the task and complete it at a higher level.

 

This can work in the other direction as well.  We know that training is not linear.  What explains a down performance day?  Many will just argue it is mechanical stress leading to it.  Fatigue is a common villain.  This does not make sense to me either.

 

There is no physiological explanation for a drop-in performance.  Studies showing peripheral fatigue days after a hard training session are looking at voluntary muscle contraction.  What controls voluntary muscle contraction?  The brain.

 

How does the brain alter perceived effort?  It analyzes all of these feedback loops and makes a decision.  This includes expectations, beliefs, mood, past experiences, outside stress, sleep, energy, etc.  This can be trained.  The lifter can also be educated and given tasks that violate those expectations and beliefs.  Sometimes they hit PRs when they feel like shit.

 

I am not saying that peripheral fatigue does not exist.  It most certainly does, but more in endurance events than a hard set of squat, bench, or deadlift.  Higher volume programs will most likely come with more measurable peripheral fatigue than high intensity programs.  Another reason why I prefer intensity.  People seem to get more banged up from the higher volumes in my experiences.

 

When we lift heavy in variations that punish inefficient positions, we are getting more bang for our buck. This is deliberate practice versus more practice.  You don’t need 10,000 hours if you train more adequately for competition and it all starts with perceptions.

Some Experimental Ideas and Perhaps Value in Backoffs

Written by Kevin Cann

 

I am writing this down to get my thoughts on paper and perhaps some reading this might have a few ideas.  The first is in terms of training mental fatigue.  I have been reading some of Noakes and Marcora’s research about a central agency responsible for fatigue.

 

Marcora has protocols to train this.  The idea is to raise perceived effort without changing physiological function.  These endurance athletes perform tests for 30-90 minutes that induce mental fatigue.

 

This is too much time. I am thinking between sets; the lifter can do a crossword puzzle or other task by themselves and without the support of the group.  I will advise the group to not cheer them on and offer them any extra support.

 

Frustration will rise to high levels here, so we will make sure we do something before they leave to switch them out of that negative mindset.  I am not trying to ruin anyone’s life.

 

I would run this like a variation for a period of time.  Remove the mental stress and perceived effort should decrease, requiring more weight to hit those perceived efforts when stressed.

 

We see this play out in the gym when a lifter feels a weight is heavy, but the team tells them to go up. They go up and hit the weight and it trains that perceived effort.  At the end of the day that is perhaps all that matters.

 

I am recruiting some members of PPS to try this out now and setting up how it is going to work. There are a few obstacles here that I need to iron out.

 

The second part of this comes from an article that John Flagg sent me about dart throwing between bench press sets.  Contextual Interference seems to increase learning in the bench press.

 

This just may be as simple as randomly switching between tasks in training as I saw in a study looking at CI on tennis players.  Here is a chance for value in backoff sets.  Perhaps if the lifter sees something breakdown in the top sets, the backoffs are something that works on that inefficiency.

 

This is how I do it in the gym quite a bit.  The randomly switching of tasks may have some benefit here.  After all, training is nothing more than practice to enhance a skill.