Scientific Principles of Strength Training

Written by: Kevin Cann

No matter what program you follow, it has to abide by the scientific principles in order for it to be effective.  The more principles that the program abides by and follows, the more optimal that it will be.  I am going to give a quick rundown of these principles.  Most of which are well explained in Dr. Mike Israetel, Dr. James Hoffman, and Chad Wesley Smith’s book “Scientific Principles of Strength Training.”


The most important principle is specificity.  There is an even an acronym for this one known as the SAID principle.  This stands for specific adaptation to imposed demands.  The body will adapt to handle the stressor in which it encounters.  This means that walking lunges will not directly make our squat stronger, it will make us better at walking lunges.

There is nothing more specific to the sport of powerlifting than taking max singles in the low bar squat, bench press with pause, and the deadlift.  It would be nearly impossible to perform max singles every time the lifter enters the gym.  This would be physically daunting as well as psychologically.  Also, there is something known as adaptive resistance.  If we do the same thing over and over our body gets used to it and we no longer get a training stimulus.

What we need to do is to build the muscles, systems, and neuromuscular coordination to be able to handle max weights on the platform.  With Boris Sheiko, I perform all of my squats low bar, I pause every bench repetition, and perform my competition deadlift at all times.

Many programs get too far away from specificity to be optimal for strength gains.  The more we change from the competition lift the less specific it becomes.  For example, a safety squat bar box squat with chains is not very specific to the competition lift as there are many variants added to the movement.

When variation, which is a principle that we will discuss, is performed the movement stays as close as possible to the competition movement.  This gives the lifter the benefit of variation without straying too far from specificity.

We need to be able to handle heavy weights and must practice that.  This is best discussed in principle number 2, overload.


The overload principle states that we must do a little more over time in order to progress.  The more can be in terms of volume or intensity.  Each lifter has a baseline of volume, generally calculated as sets x reps x weight.

There is a minimum effective dose of volume that will lead to minimum results.  There is also a maximum effective dose of volume for each lifter where if we exceed this the lifter will be unable to recover to continue to train at a high level.  A failure of being able to return to previous performance is overtraining.

The coach must analyze the lifter’s current training and technique in the lifts.  I use the Russian Strength Classification chart and the recommendations laid out by my coach Boris Sheiko.  The chart is categorized by gender, bodyweight, and total.  What I like about this chart is if you have a big total for your bodyweight than you must have developed certain qualities to lift big weights.  If you do not than the qualities such as hypertrophy and neuromuscular coordination must be improved.

Without going into extreme detail here are the recommended volumes from Sheiko

Class 2 and 3 lifter: 600-750 lifts per month

Class 1 and CMS: 800-1300 lifts per month

MS and MSIC: No recommendations as this is very individualized.  Lifters of these elite capabilities have built up their tolerance for volume over the years so much that it becomes impossible to get overload in this manner.  In this case they may perform below baseline volumes, but higher intensities.

You can see there is a wide range of recommended volumes.  This is due to the principle of individual differences which we will discuss later on.  This is why cookie cutter programs, or programs written for more than one person are not most effective.  Having a qualified coach in your corner can go a long way here.

Another benefit of using the chart is that progressive overload is built into it.  As the lifter gets stronger there are recommendations with higher volumes.  This sets up overload for the lifter’s entire career.  How we setup this monthly volume is best described in a later principle, fitness vs fatigue.

For now we are going to discuss the principle of extrapolation.


Extrapolation is not in the “Scientific Principles of Strength Training” book.  This is something that I added in from my time working under Sheiko.  There is no other aspect more important in training than technique.  In terms of principles, this falls below specificity and overload because we need to lift heavy on the platform, and if we just practice technique at 60% for 3 sets per week we will not get stronger as we fail to adhere to both specificity and overload.

The goal of training is to build a stable motor pattern.  We do this by practicing the competitions lifts at the same speeds and bar path for every repetition.  If an athlete is required to perform 5 sets of 5 repetitions at 80% and all 25 reps look different than we have trained 25 different movements.  The coach needs to identify where the athlete begins to lose technique and program the work effectively.

This is one reason why Sheiko utilizes double lift sessions in a single day.  We may perform half of the volume of squats first, then bench press, and then finish with squats.  This allows the lifter to maintain proper technique and still get in all of the repetitions as to adhere to the overload principle.

Most lifters’ technique will begin to breakdown around 85%.  This is why the majority of work is done at 85% or below in a Sheiko program.  If we go over 85% we tend to use boards or a Slingshot on the bench press and blocks on the deadlift.  This allows the lifter to handle heavier weights while maintaining proper technique.

Sticking points within the lift are not necessarily due to weak muscles, but poor neuromuscular coordination, or technique, within the lift.  For example, a good morning squat does not necessarily mean the quads are weak, but that the lifter does not possess the appropriate neuromuscular coordination to handle the weights in the squat.

Many that I have seen with this fault can lift a lot of weight on a leg press, showing the quads are not weak in strength, but weak in coordinating with the other muscles to squat heavy.  This is where we will use a variation like pin squats to teach the quads to work with the glutes and the back muscles.

Our next principle is fitness vs fatigue

Fitness vs Fatigue

I combined a couple principles from the book because I feel that they are best explained together.  Training is a balance between creating enough of a stimulus for optimal strength gain, while being able to recover.

As we train hard we accumulate fatigue.  In order for the lifter to put their best total on the platform at a given time, this fatigue must dissipate.  The more fatigue that we accumulate, the longer that it takes for our body to dissipate that fatigue so that we can realize our strength.

This is where most athletes add in deloads.  Depending on the level of recovery for the athlete deloads may happen every 3 to 7 weeks and usually follow a week of overreaching.  Overreaching is where the lifter’s volume will exceed what they can easily recover from.  Deloads are not the only way that we can dissipate fatigue.

Learn More about “Dissecting the Deload” here

Alternating higher volume, average, and lighter days can also keep a lifter fresh.  If I have an athlete performing 1000 monthly lifts and trains 4 days per week, than that athlete’s baseline is 62 lifts (1000 divided by 16).  62 lifts is the average volume day in which the lifter can recover from and still be fresh for the following training day.

A typical week will have 1-2 days that have 62 lifts, 1-2 days that stress the athlete above that number to force adaptation, and 1 day well below that number to aid in recovery.  The small volume day is usually 15-24 lifts and is the second deadlift day of the week.

Each lift has a different recovery curve.  The bench press is the easiest to recover from and my athletes will bench 3 to 4 times per week.  The squat is more difficult to recover from than the bench press and my athletes will squat 2 times per week.  The deadlift is the most difficult lift to recover from and my athletes will deadlift 1-2 times per week.  The second deadlift day is a low volume day that typically works on technique, or the lifter will lift from blocks which makes it easier to recover from.

Another way that we control the fitness vs fatigue ratio is with our next principle, variation.


Sheiko utilizes variation different than many other coaches.  Variation is any change that we make to the competition lift.  For example, a pause squat would be variation.  The use of bands, chains, specialty bars, pauses, blocks, boards, and tempo are all examples of variation.

This principle is further down the list of importance than many others.  There are many coaches and programs out there that spend too much time on this principle.  Too much variation and we lose specificity.  You can still get stronger, but remember that we are talking about optimal strength gains.

The coach should analyze each lifter’s lifts and determine the weak spots of those lifts.  From there the appropriate variations can be added.  This is how we improve technique adhering to the principle of extrapolation.  These variations should be as similar to the competition movement as possible so that it follows the principle of specificity.

Variation also aids in recovery.  Even a little variation to a movement calls upon changes by the lifter.  For example, a pause squat or squat with chains will allow certain motor units to recover so that they can come back fresh for the following squat training day.

Scientific Principles of Strength Training:  See How Your Program Stacks Up

Variation also allows the lifter to use less weight, but make it more difficult.  This not only decreases volume to keep the lifter fresh, but it also keeps them from psychological burnout.  We tend to use pauses in the weak positions of the lift.  For example, a pause on the halfway down in the squats.

Ed Coan said “If you have a weak spot of the lift, spend more time there.”  This is great advice and these variations allow us to do that.  Also, a 2 second Pause Squat in the weak spot of the lift at 70% feels much heavier than 70%.  Your body only knows effort and not weight on the bar.  This is how we can get the 90% and higher training affect while adhering to the principle of extrapolation.

Certain muscles recover more easily than others.  For example, your lateral delts don’t really acquire too much damage, but your hamstrings might.  We can use variation to give these muscles a bit of a break.  The Slingshot on the bench is a great example of this.  It gives the pecs and front delts a bit of a break as you bench.  Chains on the squat, take some pressure off of the quads out of the hole.  Having the right amount of variation at the right times keeps the lifter fresh and steadily progressing.

Next, we will discuss the principle of phase potentiation.

Phase Potentiation

I like this term that I stole from the book “Scientific Principles off Strength Training.”  This basically says that our training needs to be organized at a larger level.  Far away from competition the volume should be high and variation should be high.

As we get closer to competition volume drops, there will be less variation, and intensity rises slightly.  We test 17-22 days out and from there there is a big drop-off in volume and a gradual drop-off in intensity.  This allows fatigue to dissipate while we maintain the fitness that we have built up.

Lastly, we will discuss individual differences

Individual Differences

We are all unique little snowflakes, but not so unique that is the most important principle.  Women can typically handle more volume than men.  There are also some genetic factors that allow people to handle more volume, or make them more built to handle heavier weights.

This is why it is important to track data.  Pay attention to volumes, intensities, and see how you feel.  This is a reason why it is important to have consistency in training as well.  If you are all over the place with exercise selection, volumes, and intensities it is impossible to know what worked and what didn’t.  Do not vary your training for the sake of varying it and don’t necessarily do what your buddies are doing as it may not be best suited for you.

You can get stronger as long as some of these principles are minimally followed.  However, isn’t the goal of this sport to get as strong as possible?  That means maximum gains in strength.  Size up your program to these principles and see how it does.  If it doesn’t stack up you may need to make some changes or get a better coach.

About Kevin Cann 33 Articles
Precision Powerlifting Systems is based out of Boston, Mass. Head Coach Kevin Cann leads the raw and single ply powerlifting team through individualized programming leading up to local, regional, national, and international level USA Powerlifting meets. Coach Kevin has worked as a nutritionist and strength coach for several facilities in the greater Boston area including Harvard University and Total Performance Sports. He holds a master’s degree in kinesiology from A.T. Still University and a bachelor’s degree in health and wellness from Kaplan University. Currently, Coach Kevin competes in the 105kg class in USA Powerlifting as both a raw and equipped open lifter and was under the tutelage of former team Russia powerlifting coach and coaching legend, Boris Sheiko, from 2015-2018. Kevin utilizes many of Sheiko’s legendary methods in his programs. This includes the belief that technique is the most important aspect of training. Not only has Kevin been a long term student of Sheiko’s, he also possesses his Master’s Degree in Kinesiology, the science of human movement. The combination of his Master’s degree and time spent working with the legendary coach has awarded him with the skills to thoroughly analyze your lifts and utilize the right variations, weights, and repetitions to improve your technique and continue to steadily progress over time. Through Kevin’s experiences coaching, he has made many adjustments to the program to allow for the success of his lifters. PPS has had an Arnold qualifier every year in its existence, a top 5 national total, 2 top 10 totals, and many top 20 totals nationally. Kevin combined what he learned from Sheiko with a conjugate trining style. He learned that nothing builds 1RM strength like practicing singles. He uses a constraints-led approach with the singles. The variation allows for the athlete to continually take max singles without seeing a decrease in performance. Kevin will use variations that punish technical inefficiency and only leaves room to complete the task with a more technically efficient strategy. Heavy singles also works the psychological components of the sport. Oftentimes this goes untrained and is the largest weakness in a lifter. Along with the max effort work, PPS lifters perform sub maximal work to continue to increase technical proficiency within the lifts. Some of this technique work utilizes special exercises that Kevin learned from Boris Sheiko himself. PPS supports raw, drug free powerlifting. Kevin has coached numerous athletes that have qualified for USAPL Nationals as well as the USAPL competitions at the Arnold Sports Festival. Cost for coaching is tiered and ranges from $125 to $200 per month depending on the services required. This includes an individualized program based around your needs as an athlete as well as feedback on your lifts from videos. Text support as you are training, weekly voice memos explaining details about the upcoming week, and bi-weekly training meetings with the team to discuss training concepts is part of the tier 1 service. For more information email Kevin directly at