Muscular Hypertrophy: Back to the Basics

DeWayne Smith, MS, NASM-CES, PES, CNC | Stay Updated with NASM!

Gains don’t happen overnight. It takes your muscles time to respond and adapt to stimuli. Discover the resistance training program variables that will develop the strength gains and growth you or your client may be looking for.

If you are studying to become a CPT, the concepts discussed within will help solidify the 3rd Phase of the OPT Model. And if you are a Bodybuilder or just wanting to learn more about the science behind hypertrophy, welcome!

Table of Contents

What is general adaptation syndrome?

Over time, our bodies adapt to the stimuli we expose them to. Broadly, these stimuli can range from environmental to physiological, and even be psychological. The adaptations to these stimuli fall under the phenomenon of General Adaptation Syndrome. As Hans Selye proposed, we all respond and adapt to stressors placed on us in a predictable manner. Muscle building is no different (1, 2).

If you’ve worked out hard, but often missed on ensuring proper recovery, you may have found yourself wondering why your results were marginal at best. Very often this is also the case with others who are finding it difficult to see results in building muscle. Looking at it through this lens, their bodies are not “adapting” the way they desire them to. In muscle building this desired adaptation is known as muscular hypertrophy.

See also: Periodization Training Simplified - for more on General Adaptation Syndrome.

The four building blocks of hypertrophy

In order to define hypertrophy, an explanation of the Principles of Specificity, Overload, Adaptation, and Reversibility should come first.

1) The Principle of Specificity states that adaptations are specific to the stimuli provided.
2) The Principle of Overload is that in order for a tissue (bone, tendon, ligament, etc.) to adapt to a demand, it must be progressively overloaded.
3) The Principle of Adaptation is that the human body will adapt physiologically to the demands we place on it.
4) The Principle of Reversibility is that any gains are progressively lost when training is stopped (3).

What is Muscular Hypertrophy?

Muscular hypertrophy is an adaptation characterized by an increase in the cross-sectional diameter of muscle fibers that occurs as a response to those fibers being recruited to create increased levels of tension. More specifically, it is a function of protein balance (synthesis vs. breakdown) and consists of three mechanisms: muscle tension, muscle damage, and metabolic stress (3).

A breakdown of muscle tension

Muscle tension can be described by the mechanical tension placed on the muscle during an exercise, muscle damage by the eccentric load causing micro tearing and initiating the inflammatory response, and metabolic stress as a result of the buildup of various metabolites such as lactic acid (3). It is one of many adaptations experienced as a result of resistance training (Table 1).

Table 1. Adaptive Benefits From Resistance Training (1,2)

  • Improved cardiovascular efficiency
  • Beneficial endocrine and serum lipid adaptations
  • Increased bone density
  • Increased lean body mass
  • Increased metabolic efficiency
  • Increased muscular hypertrophy
  • Decreased body fat
  • Decreased physiological stress
  • Increased tissue tensile strength
  • Increased power
  • Increased endurance
  • Improved mood
  • Improved self-esteem
  • Improved ability to cope with stress
  • Improved perception of body image
  • Decreased symptoms associated with depression


Read also: What is Resistance Training?

Hypertrophy Workout

A hypertrophy workout consists of exercises utilizing low to intermediate repetition ranges with progressive overload. An example of this is 3-5 sets of 6-12 repetitions, performing the barbell chest press at 75-85% of the one repetition maximum (1RM) with a rest period of 1-2 minutes.

The combination of these acute variables provide the stimuli needed for muscular hypertrophy. Below (Table 2, 3) is a sample strength level, hypertrophy workout week based on a 2 day split routine. Ideally, these should be repeated for 3-4 weeks before progressing.

Simply put, if you want your muscles to grow larger, you have to utilize the proper programming to elicit the required physiological response.

In the NASM Optimum Performance Training ™ (OPT ™) model, Muscular development (hypertrophy) is Phase 3 and is part of the strength level. You can learn more within the CPT course

OPT Model Hypertrophy


Table 2. Monday: Chest/Shoulders/Triceps

WARM-UP Sets Reps Time
Self-myofascial Release
Pectoralis Major/Minor 2   30s
Upper Trapezius 2   30s
Latissimus Dorsi 2   30s
Dynamic Stretching
Push-up with Rotation 2 15  
Ball Cobra 2 15  


Stability Ball Crunch 2 15   0
Stability Ball Bridge 2 15   0
Plank 2 15s   0


RESISTANCE - horizontal loading Sets Reps Tempo Rest
Chest 3-5 6-12 Controlled 1-2min
  • Seated Barbell Shoulder Press
  • Standing Upright Barbell Row
3-5 6-12 Controlled 1-2min
  • Standing Tricep Cable Extensions
  • Bent-over Single-arm Tricep Extensions
3-5 6-12 Controlled 1-2min


COOL DOWN                                                                                          
  • Upper Body Ergometer 10min
  • Self-myofascial Release (same as warm-up)
  • Static Stretch


Table 3. Tuesday: Back/Biceps/Legs

WARM-UP Sets Reps Time
Self-myofascial Release
Calves 2   30s
IT-Band 2   30s
Lats 2   30s
Dynamic Stretching
Prisoner Squat 2 15  
Ball Combo II 2 15  


Single-leg Touchdown 2 15   0
Stability Ball Bridge 2 15   0
Plank 2 15s   0


RESISTANCE - horizontal loading Sets Reps Tempo Rest
Back 3-5 6-12 Controlled 1-2min
  • Standing EZ-bar Curl
  • Seated Single-arm Dumbbell Curl
3-5 6-12 Controlled 1-2min
  • Barbell Squat
  • Dumbbell Side Lunge
3-5 6-12 Controlled 1-2min


COOL DOWN                                                                                          
  • Elliptical Trainer 10min
  • Self-myofascial Release (same as warm-up)
  • Static Stretch


In order to optimize results you should ensure you’re following appropriate nutritional and recovery guidelines (Table 4).

Table 4. Nutritional and Recovery Guidelines for Optimizing Results (1 ,2)

Caloric Intake Positive Energy Balance
Recommended protein intake 1.2 - 1.7g/kg Body Weight
Muscle Building and Recovery Strategies
  • Consume a mixture of carbohydrates and amino acids before and immediately after workouts. Adequately replenish glycogen stores immediately after workouts by ingesting high glycemic carbohydrates and proteins in a 4:1 ratio within 30-45 minutes.
  • Meet daily carbohydrate needs.
  • Avoid high protein diets.
  • Stay hydrated. As little as 3% dehydration can hinder performance.
  • Avoid ice baths. Cold water immersion has been shown to attenuate the acute anabolic process and long term adaptations in muscles (4).


For more context on the necessary nutrition for building muscle, see this blog post on the subject!

Concluding thoughts

In conclusion, muscular hypertrophy is nothing more than a physiological adaptation to imposed physical and metabolic demands. By creating that demand and optimizing the environment to build and recover on the cellular level, we see results.

It is not something that happens overnight, as initial results are usually seen in strength gain due to neuromuscular adaptation. However, several weeks later, changes in size may be noted. The key, as with many other endeavors, is consistency.

Check out these relevant resources if you enjoyed this blog!


  1. Clark MA, Sutton BG. Lucett SC. NASM Essentials of Personal Fitness Training, 4th ed. Burlington, MA: Jones and Bartlett Learning; 2014
  2. Clark MA, Lucett SC. NASM Essentials of Sports Performance Training, 1st ed. Philadelphia, PA: Wolters Kluwer/Lippincott Williams & Wilkins; 2010
  3. Schoenfeld B, Sutton BG. NASM’s Guide to Bodybuilding, 1st ed. Assessment Technologies Institute, LLC; 2013
  4.   4. Roberts LA, Raastad T, Markworth JF, Figueiredo VC, Egner IM, Shield A, Cameron-Smith D, Coombes JS, Peake JM. Post-exercise cold water immersion attenuates acute anabolic signalling and long-term adaptations in muscle to strength training. J Physiol. 2015 Jul 14.

The Author

DeWayne Smith, MS, NASM-CES, PES, CNC

DeWayne Smith is an MS, a Corrective Exercise Specialist, Performance Enhancement Specialist, and Certified NutritionCoach for NASM.