The What, Where, and How of Hypertrophy

By Mike Hazle, Nov 03, 2021

What is Hypertrophy?

  • The most significant adaptation observed through resistance training is an increase in the cross-sectional area (CSA) of a muscle, also known as hypertrophy.
  • Most research suggests that type II fast twitch fibers have superior growth potential in comparison to type I slow twitch fibers.
  • There is a positive correlation between the CSA of a muscle and its ability to generate force although it should be noted that the extent of this positive relationship can differ in degree to both age and sex.

Where Does Hypertrophy Occur?

  • This change in muscle size is often referred to as myofibril hypertrophy as a high percentage of hypertrophy following resistance training programs results from an increase of sarcomeres and myofibrils added in parallel.
  • Skeletal muscle adaptations lead to an increase in the size and amounts of the myofibrillar contractile proteins actin and myosin which contributes to the total number of sarcomeres.
  • Under certain conditions, sarcomeres can be added in sequence, leading to a longer muscle fiber.

How Does Hypertrophy Occur?

Mechanical Tension

  • Mechanical tension is related to the force that stresses a muscle fiber to change length, width, or thickness. Muscular force is maximized close to or near 1RM.

Metabolic Stress

  • Metabolic stress is the accumulation of metabolites (lactate, inorganic phosphates, and H+).
  • The “burn” in your muscles is not lactic acid, as humans can’t produce lactic acid, and is an actual process called “Lactate”
  • Lactate is a vital component to training and is a fuel to be utilized in the absence of oxygen in the muscles.
  • Metabolic stress increases when utilizing the glycolytic system with loads under 80% 1RM.

Muscle Damage

Muscle damage is increased under the following conditions:

  • Increasing volume
  • Increasing loads
  • Utilizing a constant load
  • Eccentric contraction
  • Utilizing larger ranges of motion

General Protocols for Hypertrophy Training

  • Reps: 6-12
  • Working Sets: 2-6
  • Load: 60-85%
  • Multiplier: 1RM
  • RIR: 0-3
  • Recommended Tempo: (3,1,1,1) although variations are acceptable to balance work vs. time under tension
  • Exercises Per Session Per Region: 2-5
  • Recovery: 1 -2 minutes

About the author

Mike Hazle

Human Performance & Education Specialist

Articles by Mike Hazle >

After a 10-year career on the World Athletics Tour and the Olympics, competing in 23 countries, winning 5 National Championships medals, working with the world's elite Special Operators as a U.S. Air Force Special Warfare Combat Controller (CCT)...Mike was left injured, exhausted, and empty inside even after achieving what most would call "The American Dream." A dream full of glamour, lights, material wealth and superficial possessions.

Over the years, the lights and fireworks of the Olympic stadium have faded and the wounds of Special Operations Training have healed. Mike has learned lessons from a life in the arena of the world's most stressful environments. These lessons will carry him farther than any athletic accomplishment or experience he has ever had. Now, his unwavering mission is to help people across the world learn the tools and techniques he has mastered and help them recover from high impact, high stress careers.

In his expansive 20-year career, on top of the highest level of athletics on the World's largest stages and Military Special Operations, Mike has been educated from the best sports physiologists, nutritionists and strength & conditioning coaches across the globe. Not only that, Mike has picked up along the way a master’s degree in Sports Management, a Bachelors in Kinesiology, a National Strength and Conditioning Association (NSCA) Certified Strength & Conditioning Specialist (CSCS) and Cross Fit certifications. Mike has also spent 6 years on the resident athlete advisory board at the US Olympic Committee's (USOC) Olympic Training Center in Chula Vista, CA.