part 2 lecture 1

Introduction to Skeletal Muscle Training

• Focus on clinical impact of specific training on skeletal muscle.

• Balance of muscle protein turnover: synthesis vs. breakdown.

Muscle Protein Turnover

• Ongoing process of muscle protein synthesis and degradation.

• Homeostasis: a balance signifies health; disruptions can lead to problems.

• Hypertrophy: occurs when muscle protein synthesis exceeds degradation.

Effects of Hypertrophy

• Correlation between muscle size and performance: greater muscle size = increased strength.

• Increased horsepower production capacity as a result of hypertrophy.

• Common causes of muscle hypertrophy:

  • Normal growth.

  • Mechanical loading (e.g., weight training) leading to structural adaptations.

Structural Changes During Hypertrophy

• Sarcomeres: more are laid down in parallel as muscles hypertrophy.

• Constant number of muscle fibers occupy the same tendon length, leading to:

  • Increase in fiber size.

  • Change in pennation angle.

• Impacts of changes in fiber size and pennation:

  • Greater capacity for force production.

  • Reduction in contraction speed (velocity).

Performance-Specific Muscle Training

• Importance of tailoring training to performance demands and muscle fiber types:

  • Example: Usain Bolt (sprinter) requires more type II fibers; therefore, his training focuses on power.

  • Example: Mo Farah (marathon runner) focuses on type I fibers for endurance.

Muscle Length and Strength Generation

• Stretching muscles can stimulate protein synthesis and increase sarcomeres in series, leading to increased muscle length.

• Adaptations during growth affect muscle length and strength generation ability.

• Clinical considerations:

  • Longer muscles can alter the force-length relationship impacting strength generation.

  • Potential negative outcomes from altered balances in muscle length and strength performance.