Fitness Knowledge
Kip Landergren
Contents
Overview
Fitness is physical competency.
It is the ability to
- move your body as you intend and
- to perform that movement efficiently, accurately, and without degradation for the entire duration it takes to accomplish
Training for fitness is the process by which you leverage your body as a mechanical—yet still fundamentally biological—system to produce adaptations changes necessary to reach your goals.
The process is a very sensitive feedback loop and one very gratifying to pursue!
Core Idea
Stimulus during exercise results in adaptation during recovery.
Careful, deliberate shaping of stimulus and management of recovery results in increased fitness.
Key Concepts
Specific Adaptation to Imposed Demand (SAID) Principle
The adaptation is going to be a reflection of the demand imposed.
Henneman’s Size Principle
Motor units (neurons + associated muscle fibers) are recruited in a fixed order based on motor neuron size:
- low-threshold (slow-associated) first
- high-threshold (fast-associated) later
as net excitatory input to the motor neuron pool increases.
Net excitatory input is the sum of inputs from:
- descended brain signals
- sensory feedback
- spinal circuits
It isn’t enough to just think “REALLY LIFT THIS WEIGHT HARD”, you actually have to have a force on the system sufficient to reach the excited state.
Interesting note:
The size activation has to do with the biological application of Ohm’s law where the smaller cross section of the membrane results in higher resistance, meaning less current is required to produce a given voltage change.
Training for Fitness
Training can be thought of as the management of:
- stimulus, where the body is stressed through exercise
- recovery, where the body adapts to that stress
to accomplish a desired level of fitness.
Some adaptations from exercise include:
| skill | the ability to coordinate movement efficiently and accurately |
| speed | the ability to move at maximal velocity |
| strength | the maximal force you can produce |
| power | the rate of force production (force × velocity) |
| hypertrophy | an increase in muscle fiber size |
| muscular endurance | the ability of a local muscle to sustain repeated contractions |
| anaerobic power | high-intensity work primarily without oxygen (~30 seconds to ~2 minutes) |
| VO2 max | maximal aerobic power; highest rate of oxygen utilization (~3 to ~12 minutes) |
| long duration endurance | the ability to sustain submaximal work for extended periods (30+ minutes) |
Certain adaptations can positively interfere with each other while others compete.
Each adaptation requires a specific stimulus to develop. That stimulus is controlled through modifiable variables.
Some modifiable variables for shaping stimulus (and the subsequent adaptation) are:
| exercise choice | the movement pattern and muscle groups being trained |
| intensity | relative effort (e.g. %1RM, velocity, or %max heart rate) |
| volume | total work performed (often simply: sets × reps × load or duration) |
| rest intervals | the time between efforts, influencing recovery and energy system contribution |
| progression | the systematic increase or variation of stimulus over time |
| frequency | how often training is performed |
Developing a training program involves:
- defining the target adaptations
- manipulating modifiable variables to create the appropriate stimulus
- organizing that manipulation over time to reinforce the desired adaptations
Galpin’s Laws of Strength
Three laws:
- progressive overload
- types of exercises do not determine adaptations; application determines adaptations
- strive for all joints through all range of motion
Progressive Overload
Adaptation occurs in response to sufficient physiological stress, followed by recovery.
Types of physiological stress include:
| mechanical | tension placed on tissues (e.g. force and stretch under load) |
| cardiovascular | strain on the heart and circulatory system (e.g. heart rate, blood flow demands) |
| metabolic | accumulation of byproducts from energy turnover (e.g. lactate, ions) |
| neural | demands on the nervous system (e.g. motor unit recruitment and firing rates) |
How should one think about what level of stress is “sufficient” to create an adaptation?
This can be estimated using lagging indicators (e.g. performance trends, fatigue, soreness), but is best understood as falling into one of four categories:
| below threshold | maintenance zone: stress does not drive further adaptation |
| at threshold | minimum effective dose: triggers adaptation, but slowly |
| above threshold | overload zone: strong adaptation signal but still recoverable |
| too much | maladaptive zone: major fatigue and risk of injury increases |
Stress is best tuned through progressive overload, the process of gradually increasing demands on the system beyond its current threshold for adaptation while remaining recoverable.
This increased demand is created by manipulating the modifiable training variables.
Some example manipulations include:
| exercise choice | increasing coordination or stability demands (e.g. machines to free weights) |
| intensity | increasing load or effort (e.g. 50% 1RM to 85% 1RM) |
| volume | increasing total work (e.g. more sets, more reps, or more load) |
| rest intervals | adjusting recovery to alter performance or energy system stress |
| frequency | increasing how often a stimulus is applied through training |
For overload to drive adaptation, the stimulus must be:
- specific to the desired adaptation
- sufficient to disrupt homeostasis
- recoverable so the system can adapt
By systematically controlling the magnitude, specificity, and recoverability of overload, one can reliably drive targeted adaptations over time.
Exercise Choice, Application, and Adaptation
An exercise is an activity that gets you into the movement pattern you want to train. This movement pattern is often emphasized as being important to execute with good form.
Good form is a bit of a loaded term though, as it really captures two criteria:
- that the movement fulfills certain physical requirements related to body position
- that the nervous system engages the desired muscle groups
For example:
It is possible to perform a chin up that looks correct but does not adequately engage the lats. Striving for good form means that the intended muscle groups are the dominant contributors to its execution.
Starting out with simple movement exercises:
- increases likelihood of executing with good form
- increases long term success
- reduces risk
Progressing to a technically difficult or complex movement becomes beneficial when you have the strength, skill, experience, and coaching to match.
The chosen movement pattern is itself not sufficient to determine adaptation: it must be combined with the actual application of effort. This application, chosen by adjusting the modifiable variables, shapes the stimulus the body experiences and thereby drives the adaptation.
Thus exercise choice does not determine adaptation, it is the application that determines adaptation.
All Joints Through All Range of Motion
A joint is the connection of two or more bones through a series of muscles and connective tissues that allows the exertion of force on the surrounding environment.
All joints have a safe operating distance governed by the nervous system. The nervous system has taken all that the joint has experienced—the bends, lifts, and injuries—up to now and determined a safe operating distance that joint can traverse. To maintain this distance it sends control signals to muscles to relax or tighten depending on where the joint is in its range of motion. When you feel some limitation in the distance you are able to stretch this is due to the nervous system tensing the muscle to keep it within a safe range. It is not that your tendons are “too tight”. It is not that your fascia is too stiff (stiffness does occur as a result of exercise, but not sufficient to wholly limit the range of motion of a joint). It is predominately a mechanism of the neural system firing to keep tissue from entering a perceived danger zone.
Training a joint through its current range of motion—especially at the limits—teaches the nervous system that it is safe to perform the movement. It develops, and then “learns” that it has strength at these bounds to control the position of tissue and not put itself into injury. This safe range of motion can increase as fitness increases because the nervous system accumulates data on what is actually safe. Intentional stimulus to this process—like through stretching and strength training—can cause adaptations where the body is able to perform normal movements with greater control and exceptional movements with lower risk of injury.
Thus a level of general fitness to strive for is to have strength through all the movements of the body, through all of its ranges of motion.
Hypertrophy
Hypertrophy is the increase in muscle fiber size. Generally, everyone benefits from hypertrophy training.
Stimulus that results in hypertrophy adaptation involves:
- metabolic stress
- mechanical tension
- muscular damage
The most reliable progressive overload variable for hypertrophy is to approach failure during the effort.
This will:
- recruit all variants of available motor units (e.g. slow and fast twitch)
- balance stimulus-to-fatigue better than maximal effort
- result in the maximum growth of the muscle fibers
The measurement of approaching failure is to estimate what would be considered the number of reps “in reserve” (RIR) you have left when stopping. Hypertrophy stimulus is significant when an effort is done with 1-3 RIR.
A simple way to accomplish 1-3 RIR:
- perform a rep
- ask yourself: “Can I do 3 more?”
- stop if “no”
- repeat if “yes”
The top contour of a hypertrophy-based workout plan:
- ~10-20 working efforts (sets that approach failure) per week, per muscle group
- full range of motion
- 8-30 reps per working set
- stop when:
- form degrades
- bar speed significantly slows
- 1-3 RIR
- choose weight according to above range of motion, rep, and stop conditions
Going to “near failure” during a set does not mean the set was done with high intensity. Intensity is measured relative to your one-rep maximum (1RM), and, generally, 75%+ 1RM is considered a high intensity effort. A hypertrophy-based exercise done with 40% 1RM, between 8 and 30 reps, 1-3 RIR, is not considered “high intensity” despite the fact you really have to work for those last reps!
During the effort, keep the following in mind:
- on a scale of 1-10, the “burn” should be about a 3, up to a 5 (higher than that introduces too much damage)
- think: I am trying to challenge this muscle (recruits different nerves). intention matters.
Evaluation for efficacy:
- did you feel muscle contract?
- did you get a pump?
- did you feel sore (but not destroyed) the next day?
The following variables are associated with hypertrophy:
| positive association | neutral or negative association |
|---|---|
| nearing failure | intensity |
| volume | |
| larger range of motion | |
| recovery |
Strength
Strength is the ability to maximally apply force to a movement.
It requires a combination of:
- nervous system signal
- muscular contraction
- connective tissue
The most reliable progressive overload variable is intensity.
Intensity is measured relative to your one-rep maximum (1RM), and, generally, 75%+ 1RM is considered a high intensity effort.
The top contour of a strength-based workout plan:
- higher frequency is OK (but not required; can do twice per week per muscle group)
- higher intensity (+85% for pros, +75% for mid, and anything for beginners)
- sufficient to do 3 sets, building to highest intensity on 3rd
- high rest interval to maximize intensity (too little rest and you can’t get the output to cause adaptation)
- OK to superset alternate muscle groups during rest interval
- think: I am trying to move this weight, and I don’t really care how (i.e. don’t think about contracting specific muscles, think about getting that weight up there) which will recruit different nerves than e.g. hypertrophy. intention matters.
Minimal “3-5” strength plan (also applicable to power):
- 3-5 exercises
- 3-5 reps targeting 85% intensity
- 3-5 sets
- 3-5 minutes rest
- 3-5 times per week
Intensity doesn’t always have to be maximal. Alternate example of an exercise’s effort:
| set | reps | intensity |
|---|---|---|
| 1 | 10 | 50% 1RM |
| 2 | 8 | 60% 1RM |
| 3 | 8 | 70% 1RM |
| 4 | 5 | 75% 1RM |
The following variables are associated with strength:
| positive association | neutral or negative association |
|---|---|
| intensity | volume |
| rest | |
| larger range of motion | |
| frequency |
Endurance
Endurance is 30+ minutes sustained effort of an activity.
Start with a concentric movements:
- biking
- swimming
- rowing
- sled push
- uphill walking / running
- farmer’s carries
Be wary of eccentric lading:
- the foot impacting the ground during a run
- running downhill
as these are extremely high forces performed with high repetition, greatly increasing risk of injury. Knee, back, shoulder, and even neck pain result from movement compensation to handle these high loads. Which means you need the tissue development to support the effort.
Avoid pushing to fatigue during an endurance-based activity. The combination of loading and repetition in a fatigue state maximally increases risk of injury.
The top contour of an endurance-based workout plan:
- 150-180 minutes of zone II (ability to talk), roughly split over 3-4 sessions, per week
- 4-8 sets of ~90 seconds touching maximum heart rate, in a single session
- focus on just breathing through your nose
- 80% intensity. e.g. 1:1 800m:rest, repeated (note: anything that takes between 2 and 6 minutes, adjust length accordingly)
Daily frequency is fine. Can safely combine with strength or hypertrophy training. Interference effect on limiting strength gains is overblown. Max heart rate tends to be complimentary with strength and hypertrophy.
Note: muscular endurance from planks and wall sits have carry over effects of improving posture (spinal muscles) and body movement (shoulders, etc) throughout day, reducing risk of injury.
The following variables are associated with endurance:
| positive association | neutral or negative association |
|---|---|
| volume |
Speed
- higher frequency is OK
- low intensity
- low volume
- maximal velocity
| positive association | neutral or negative association |
|---|---|
| higher frequency | intensity |
| rep range | |
| volume |
Power
Power is velocity × strength. It benefits from speed and strength work.
The top contour of a power-based workout plan:
- higher frequency is OK
- intention matters: really think about how fast you are going to move
Minimal “3-5” power plan (also applicable to strength):
- 3-5 exercises
- 3-5 reps targeting 85% intensity
- 3-5 sets
- 3-5 minutes rest
- 3-5 times per week
The following variables are associated with power:
| positive association | neutral or negative association |
|---|---|
| whole body movement | single joint isolation |
Tools
How to Activate a Reluctant Muscle
Cuing
Have a partner physically tap the muscle that you wish to engage.
Flexing
Look at the muscle (at the mirror flexing, or during the exercise) and focus your attention solely on contracting that muscle.
Eccentrics
An eccentric is any exercise where a muscle elongates under load. Most normal exercises go through a full range of motion: full extension, full contraction, and back to full extension. Eccentrics are simply a chopped version of that: start from full contraction and slowly lengthen to full extension.
Examples:
- descending pull ups
- descending calf raises
Muscles are able to exert greater forces eccentrically while still maintaining control and thus the exercises are great for hypertrophy and strength development.
Isometrics
An isometric exercise is one where a fixed-length position is held for some duration, possibly under load.
By holding a fixed-length position the muscle must maintain a strong contractive force to both:
- keep the body position constant
- compensate for tendon lengthening
This benefits:
- the tendon, which, when lengthening under load, receives a strong adaptation signal
- the muscle, which must maintain the contraction
- the nervous system, which must sustain its contractive signal
Additionally, the lack of repeated muscle contractions prevents regular flushing of metabolic byproduct leading to “the burn” sensation and further adaptation signaling.
How to Manage Recovery
Improving fitness involves managing total stress vs. your recovery capacity.
Any time the total stress load outpaces recovery capacity, you're either going backwards in your physical ability or you're reducing adaptability.
Either reduce stress intake or increase recovery capacity.
On Soreness
Soreness is not a great indicator of workout efficacy. The pain we associate with severe soreness is from swelling and pressure resulting from calcium disruption during exertion—things that are not contributing directly to adaptation compared to say the microtrauma of muscle fibers. It is a useful signal to understand the demand placed on the body during the exertion but striving for soreness should not be a goal. Soreness is best used as an indicator for whether you overdid things during your prior workout. Recovery is critical to adaptation and time lost to soreness takes away from long term adaptation progress.
On Nervous System Fatigue
To gauge nervous system fatigue we need physical efforts that are:
- disproportionately sensitive to nervous system contributions vs. muscle contraction
- have very low variability between efforts
- not significantly taxing or dangerous at a high intensity
These include:
- squeezing your hand into a fist
- vertical leap
- rapid finger taps (in a 60s interval)
Testing any of these in the morning after a workout will give insight into your nervous system state. Any significant deviation lower indicates your nervous system got sufficient stimulus during the workout.
Squeezing your hand into a fist is especially convenient because when done every morning upon wake up you will quickly develop the ability to distinguish the sensation of “muscle weakness” vs. “nervous system activation weakness”.
I find it hard to describe in words but muscle weakness feels like:
“I want to squeeze harder but am missing strength”
and nervous system feels like:
“I am squeezing harder but the force still doesn’t change”.
On Heat
Heat (e.g. hot bath) can:
- increase growth hormone
- increase basal dilation
- improve ability to sweat
- augment hypertrophy
On Cold
Cold immersion (more pronounced effect with moving water to remove the thermal envelop) can:
- increase dopamine
- increase epinephrine
but a cold shower doesn’t cut it.
On Supplements
Talk to a professional. Top 3, according to Galpin:
- sodium bicarbonate. taking a very very small amount (half to one teaspoon per 10 oz water) ~45 minutes before a workout reduces the build up of lactic acid because it makes the blood slightly basic. slightly niche. useful only for very high exertion efforts.
- beta aline. fatigue blocker.
- creatine. muscles. mental. everything. the best tested and most easily recommendable supplement.
Breathing During Exercise
Breathe, if you can, throughout the entire exercise. Don’t worry too much about like “deep breath in on eccentric” or “exhalation on contraction”. If you have the core strength to brace and breathe continuously: do so.
Breathing is about one of two things:
- combating build up of CO2
- combating low O2
Have a breathing strategy for rest periods: are you trying to resupply as much oxygen as possible? are you trying to calm your nervous system?
Some breathing methods:
| 2:1 | exhale:inhale | |
| box breathing | 1:1:1:1 | inhale:hold:exhale:hold |
How to Workout During Injury
Listen to a professional.
Assuming this is a minor injury where you feel pain during a movement: back off effort all the way down to just below that threshold of that's what aggravates the issue and train there.
This does two things:
- improves tissue tolerance
- desensitizes area that movement means pain
Hydrating Properly
Rough daily guide: half your weight in lbs in ounces. e.g. 200 lbs targets 100 oz.
Consider:
- weighing yourself before and after a workout
- drinking back 125% of the water your lost
People fall into one of two groups:
- high salt sweater
- low salt sweater
Easy test to determine: does your hat or clothing develop white bands after sweating? If yes, you are likely a high salt sweater and should consider consuming slightly more salt in your diet. Otherwise no change advised.
If you are losing more than 1% of your bodyweight during the endurance exercise: carry water with you.
Fitness Terminology
- HIT
- training to failure 6x month in very short intervals
- Heart Rate Variability (HRV)
- fatigue metric
- Specific Adaptation to Imposed Demand (SAID) principle
- the result of your training is a reflection of the demand you imposed
- brace
- (maintain intramuscular, intra-abdominal pressure)
- eccentric exercise
- the elongation of a muscle under load. some eccentric exercises are when the force applied to the muscle/tendon system just exceeds its maximal contractive force and there is a forced—but still controlled—lengthening (e.g. negative chin ups)
- gene cascade
- chain of gene activations where each step controls the next, shaping how cells develop, specialize, and function over time. (how the piano was built and tuned in the first place)
- hypertrophy
- (muscle fiber) size increase
- motor neurons
- upper and lower
- multi joint movement
- e.g. full snatch
- neural signals
- real-time control (like pressing keys on a piano)
- pennation angle
- angle of which muscle fibers lay relative to the bone
- prime muscle
- the primary muscle used in a movement
- proprioceptive feedback
- the signals from sensory inputs back into the nervous system to generate knowledge of where the limbs are
- pull exercise
- moving weight perpendicularly toward the body
- push exercise
- moving weight perpendicularly away from body
- single joint movement
- e.g. bicep curl
- supersetting / supersets / super sets
- working alternative muscle groups during rest inervals
- synergistic muscle
- secondary or tertiary muscle used in a movement
- working set
- a set of exercises that is not warm up and in a specific range of difficulty that you are intentionally trying to achieve