3 Major Keys to Building Strength and Size

On the surface, stimulating muscle growth is easy: just drink coffee, eat meat and lift heavy! Weight training will work as long as you’re progressively increasing the demand placed on the muscle over time (either by adding more weight, doing more reps at a given weight, doing more sets, etc.). But it’s still interesting to understand the factors that can contribute to making your muscles grow. We know that lifting weights builds muscle, but why?

Key No. 1: Intramuscular Tension

This refers to how hard a muscle must be contracted during the performance of an exercise. As such, it’s directly correlated with the amount of force you have to produce.

The intramuscular tension refers to the effort of the muscle necessary to produce a certain force output. We already know that force is equal to mass x acceleration, so it should also be evident that intramuscular tension will be influenced by the magnitude of the load and the acceleration one has to transfer to the resistance. In simpler words, you can increase intramuscular tension by increasing the weight or the acceleration (or both).

  • Intramuscular tension is increased if the resistance is greater and acceleration is preserved
  • Intramuscular tension is increased if the acceleration is greater and the resistance preserved
  • Intramuscular tension is increased if both acceleration and load are increased.

Therefore, if the resistance is continually increased eventually acceleration will diminish which will reduce tension and the stimulus on the muscle. This is why strength or size isn’t build by maxing out or by doing light weights slowly.

  1. Maximal reps of 1 -3 of +90% will fatigue quick and reduce acceleration producing low intramuscular tension for a too short period of time to elicit any growth response.
  2. 30+ reps of less than 40% will have too low of a resistance to elicit any growth response
  3. Focusing on strength at about 70% to 90%  will allow maximal acceleration and the high possible resistance.
  4. Focusing on hypertrophy at about 60% to 80% will allow maximal acceleration and high resistance for a great amount of volume.

Key No. 2: Time Under Tension

I talk about this in my blog ‘Physics lesson for TUT‘ that the stimulation of muscle growth and strength to be a function of ‘time under tension’ (TUT). Popularised by Charles Poliquin taking the concept too literally and timed protocols such as 3-1-1 for strength or 5-1-5 for hypertrophy development became very popular. To truely understand real ‘TUT’ you must understand Newton’s 2nd law of motion with Force (F) equals mass (kg) times acceleration (m/s2).

So when it comes to ‘time under tension’ tension is calculated by mass X acceleration (force). In terms of weight training, the mass is what we refer to as the ‘weight’. Acceleration is the rate of change of speed of the weight (against gravity). The factor of time can be measured through volume which will need to be achieved in the shortest units of time for maximum velocity. So in simple terms: maximum intramuscular tension is created by lifting as heavy a weight as possible, as fast as possible through multiple reps and sets.

So in simple terms: maximum intramuscular tension is created by lifting as heavy a weight as possible, as fast as possible through multiple reps and sets.

You must note that I talked about “Total” TUT. What I mean is that the cumulative TUT for all the sets of an exercise will be much more influential than the TUT per set. This explains why you must do more sets when training with heavier weights and lower reps; the TUT for each set is low, so to maximize gains you must increase the Total Time Under Tension by adding more sets.

So what does that tell us?

  1. If the tension is too low during an exercise, even when performed at a high volume, it will not lead to much in the way of size or strength gains.
  2. If the volume is too low, even if the tension is very high, it will not give you much size or strength gains.
  3. Ideally you want to maximize tension by using either a heavy weight, or lifting the load as fast as possible while lowering it slowly.
  4. If you select a load that you can do for 1-5 reps, you must do more sets to get a strong growth stimulus.

For Performance the Nervous System is Key

Let us use an example;

Feats of strength by apparent weaklings are common. Just think of the frail middle-aged women who suddenly possess superhuman strength when her child gets trapped under an automobile or another heavy apparatus. There are many documented cases in which the woman was actually able to lift the car off the ground to free her child. A feat that she could not repeat in a million years under normal circumstances. Sure her strength was potentiated by adrenaline and other hormones, but the muscles that lifted the car were the same she already had, new muscles didn’t blossom out of nowhere to help her lift the car! The stress and extreme stimulation from the situation simply improved her capacity to produce force with the muscles she already had! Neurotransmission was improved, protective mechanisms were shutdown, sensory feedback was ignored … All of this made her able to work to her full potential, something that we don’t come remotely close to doing under regular circumstances.


By now it should be clear to you that the limit in force production lies in the nervous system. The greater the proportion of his strength potential an athlete can use is, the better he’ll be. The difference between absolute strength (the full potential for strength production) and limit strength (the actual maximum strength that an individual can voluntarily produce) is termed the strength deficit.

What make me strong?

  1. Muscles
    A bigger muscle is a potentially stronger muscle. The contractile capacities of the muscle fibers and the ratio of fast twitch/glycolitic fibers to slow twitch/oxidative fibers also has an influence.
  2. Muscle receptors
    Some receptors will act as an inhibiting factor in force production. Notably the Golgi Tendon Organs, which act as a protective mechanism and lead to a partial shutdown of the muscles if the tension present is too high. Other receptors, such as the muscle spindles, will increase force production by provoking an elastic effect (myotatic reflex) when the muscle is stretched.
  3. Nervous system
    The efficacy of the nervous system influences force production by modulating motor unit (muscle fiber) activation, their synchronization, and the rate of contraction of the motor units. In simpler terms, the more efficient your CNS is, the more you can get out of the muscles you already have!
  4. Mindset
    Sport psychology his heavy underrated and is by far the most important to overcome mindset limitations or the above won’t matter.
  5. Other factors: Motivation, environment, stress level, recovery etc.

I’ll use myself as an example. For the past 5 years I concentrated mostly on powerlifting, and the first 3 years I solely focused on strength, not size. But during my last 2-3 years in powerlifting I would include 4-12 weeks of bodybuilding-type training once or twice per year. Oddly enough, I found that during those 4-12 weeks I could gain more muscle size than most guys doing bodybuilding training year-round would gain in 6-12 months!

Because before powerlifting, I’m talking pre-2012, I competed in bodybuilding, training for mostly size and was about 80kg@ 5% on stage. Once I took up powerlifting I shot up to 100kg at about 13% in few months. Then the next 2 years I maintained 15-20% getting up to a max 112kg. It not until I made the focus on dedicated bodybuilding/hypertrophy cycles I’ve managed to gain a lot of quality muscle getting up to 130kg@20%. I truly believe that without my foundation in strength training my gains would have been much slower and vis versa, I am much stronger having a lot more muscle.

While there have been no studies on the subject, I speculate that the higher adaptive demand of powerlifting/ strength training turns the body into a more adaptive machine, giving your body the capacity to adapt with greater training stress. So when you switch to a bodybuilding cycle, you had the physical capability to produce greater hypertrophy stress, the body is able to gain at a much faster rate because you are strong.

This doesn’t mean that one should stop doing bodybuilding training, but rather that anybody wanting more size should include phases of strength, power, hypertrophy training.

Key No. 3: Strength is a Skill

Mastering any physical skill takes practice/training. Practice is repetition of an action with the goal of improvement. Our philosophy is do not practice a single bad rep, don’t train to fail. “bad reps” will re-enforce your neural pathways to do exactly that… “bad reps”. Its not the amount of training you put in, it’s the quality and effectiveness of that training that counts.  Effective training is consistent, intensively focused and targets content or weaknesses that lie at the edge of one current abilities. So if effective practice is the key the how can we get the most out of our training time;

  1. Need to be in the right environment away from distractions. A place the keep your focus at the task at hand i.e. powerlifting club
  2. Start slowly or with trainings (i.e. bands, boxes etc) in a way that forces quality repetition.
  3. Gradual increase in speed and load of the quality repetitions and you have a better chance hitting bigger weights.
  4. Studies show that elite athletes spend 50 to 60 hours per week to there allotted task weather that includes training, recovering, eating, meditating, mental practice etc and effective practice is allot in a bunch of short durations. So frequency, focus, consistency and rest.
  5. Mentally Practice. Once a physical skill has been practiced you can then reinforce that action by imaging it. Studies show this can be just as effective as the physical action itself.