The What, Where, and How of Hypertrophy
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 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 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 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
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