🧬 How and Why Do Muscles Grow?

Muscle hypertrophy—the increase in muscle size—occurs primarily through three scientifically supported mechanisms:

1. Mechanical Tension

Definition: Mechanical tension refers to the force generated through resistance training when muscles contract under load.

Training Protocol:

• Lift weights in the 75–85% 1RM range.

• Perform 6–12 reps per set.

• Use compound lifts (e.g., squats, deadlifts, presses).

• Train near failure (1–2 reps in reserve) to stimulate hypertrophy without unnecessary fatigue.

Quote:

"Mechanical tension appears to be the most important factor for muscle growth." — Dr. Brad Schoenfeld, Ph.D., CSCS

Citation:

• Schoenfeld, B. J. (2010). The mechanisms of muscle hypertrophy and their application to resistance training. Journal of Strength and Conditioning Research, 24(10), 2857–2872.

2. Muscle Damage

Definition: Microscopic damage occurs when muscles are challenged, especially during eccentric contractions.

Training Protocol:

• Incorporate slow eccentric movements (e.g., 3–5 seconds lowering phase).

• Use novel exercises or new stimulus sparingly.

• Allow sufficient recovery between sessions.

Note: Muscle soreness (DOMS) is not a reliable measure of effective training.

Quote:

"Eccentric training is particularly effective for promoting muscle damage and subsequent hypertrophy, though it must be balanced with adequate recovery." — Dr. Hyunsoo Kim, et al.

Citation:

• Kim, H., et al. (2019). Eccentric exercise-induced muscle damage and its effect on muscle function, inflammation, and metabolism. International Journal of Molecular Sciences, 20(23), 5675.

3. Metabolic Stress

Definition: This refers to the accumulation of metabolites (e.g., lactate, hydrogen ions) during high-rep, short-rest training.

Training Protocol:

• Use 15–30 rep sets with <60 seconds rest.

• Apply methods like supersets, drop sets, and blood flow restriction (BFR) training.

Quote:

"Metabolic stress may act as a hypertrophic stimulus by increasing hormonal responses and cellular swelling." — Dr. Brad Schoenfeld

Citation:

• Schoenfeld, B. J. (2013). Potential mechanisms for a role of metabolic stress in hypertrophic adaptations to resistance training. Sports Medicine, 43(3), 179–194.

🔄 The Science of Training for Growth

Progressive Overload

• Gradually increase training stimulus (e.g., more weight, volume, frequency).

• Essential to force adaptation and continued growth.

Volume and Frequency

• Aim for 10–20 sets per muscle group per week.

• Train each muscle group 2–3 times weekly.

Recovery

• Prioritize 7–9 hours of sleep per night.

• Manage fatigue through deloads and periodization.

• Nutrition plays a crucial role in recovery and adaptation.

🥗 Nutrition: Fueling Muscle Growth

Energy Balance

• Caloric Surplus: To build muscle, consume more calories than you burn.

Components of Energy Expenditure:

• BMR (Basal Metabolic Rate): Calories burned at rest.

• NEAT (Non-Exercise Activity Thermogenesis): Movement outside of structured exercise.

• EA (Exercise Activity): Calories burned through workouts.

• TEF (Thermic Effect of Food): Calories used to digest and absorb food.

Macronutrients

• Protein: 1.6–2.2g per kg of bodyweight per day.

• "Protein intake is the cornerstone of muscle repair and growth." — Dr. Eric Helms

• Carbohydrates: Primary fuel for resistance training.

• Fats: Essential for hormone production (aim for 20–35% of total intake).

Citation:

• Helms, E. R., Aragon, A. A., & Fitschen, P. J. (2014). Evidence-based recommendations for natural bodybuilding contest preparation: nutrition and supplementation. Journal of the International Society of Sports Nutrition, 11(1), 20.

Meal Timing

• Distribute protein evenly (20–40g every 3–5 hours).

• Post-workout nutrition helps recovery, but total daily intake is most important.

🧠 Final Thoughts

Muscle hypertrophy is a result of applying intelligent resistance training that balances mechanical tension, muscle damage, and metabolic stress—all supported by progressive overload and sufficient recovery.

Nutrition supports these processes through caloric surplus, adequate protein, and structured meal timing.

"Hypertrophy is not just about lifting weights—it's about lifting with intent, consistency, and fueling properly." — Dr. Andy Galpin

✅ Takeaway

• Train hard and smart.

• Prioritize progressive overload.

• Fuel with purpose.

• Recover intentionally.