Resistance Training: Blocking, Muscle Size, and Optimal Hypertrophy Strategies

Does blocking increase size?

While "blocking" can maintain constant muscle tension and increase metabolic stress, it generally does not optimize muscle hypertrophy compared to training through a full, controlled range of motion, which is crucial for maximizing mechanical tension and stretch-mediated growth.

Understanding "Blocking" in Resistance Training

In the context of resistance training, "blocking" typically refers to the practice of intentionally stopping a movement short of its full anatomical range of motion (ROM) – either at the lockout (full extension) or the deepest stretch (full flexion) phase. This technique is often employed with the rationale of:

• Maintaining Constant Tension: By avoiding the "lockout" or "resting" position, the muscle is theoretically kept under continuous tension throughout the set.
• Joint Protection: Some lifters may block to avoid hyperextension or excessive stress on joints at the end ranges of motion, particularly in exercises like leg presses or bench presses.
• Targeting Specific Muscle Regions: The belief that by shortening the ROM, one can isolate or emphasize a particular part of the muscle's contraction curve.

The Mechanisms of Muscle Hypertrophy

To understand how "blocking" impacts muscle size, it's essential to revisit the primary drivers of muscle hypertrophy:

• Mechanical Tension: This is considered the most significant factor. It refers to the physical force exerted on muscle fibers during contraction. High mechanical tension, particularly under load and through a long range of motion, signals muscle cells to grow. This includes both the active tension from contraction and the passive tension from stretching under load.
• Metabolic Stress: The accumulation of metabolites (e.g., lactate, hydrogen ions) within muscle cells during high-repetition, short-rest training. This can lead to cell swelling (the "pump") and may contribute to hypertrophy through various signaling pathways.
• Muscle Damage: Micro-tears in muscle fibers caused by unaccustomed or intense exercise, especially during the eccentric (lowering) phase. This damage triggers a repair process that, over time, can lead to muscle growth and increased resilience.

Blocking and its Impact on Hypertrophy Mechanisms

Let's analyze how blocking interacts with these key hypertrophy mechanisms:

• Mechanical Tension:
  • Potential Benefit: By avoiding lockout, constant tension can be maintained on the working muscle, preventing momentary relaxation.
  • Significant Drawback: Reducing the total range of motion inherently limits the duration and magnitude of mechanical tension applied across the full muscle length. Crucially, the deepest stretch and the full contraction often provide unique tension profiles that are highly beneficial for hypertrophy. Research consistently shows that training through a full ROM leads to greater muscle growth, partly due to increased passive tension during the stretched position.
• Metabolic Stress:
  • Potential Benefit: Maintaining constant tension can increase time under tension for the muscle, potentially leading to greater metabolite accumulation and the "pump."
  • Consideration: While effective for metabolic stress, this can also be achieved with full ROM training by controlling tempo and minimizing rest between repetitions. Blocking isn't uniquely superior for this mechanism.
• Muscle Damage:
  • Potential Drawback: The eccentric phase, especially under load and through a full stretch, is a potent inducer of muscle damage. By blocking the full range, particularly the deepest stretch, you may reduce the amount of beneficial muscle damage that contributes to the repair and growth process.

The Role of Range of Motion (ROM)

Extensive research in exercise science supports the notion that training through a full, controlled range of motion is generally superior for maximizing muscle hypertrophy. This is because:

• Greater Muscle Fiber Recruitment: A longer ROM ensures that more muscle fibers are recruited and worked throughout the entire movement.
• Increased Time Under Tension (Effective): While blocking can increase constant tension, a full ROM increases the total effective time the muscle spends under tension, especially at the stretched lengths where growth signals are strong.
• Stretch-Mediated Hypertrophy: The mechanical stress of stretching muscle fibers under load, particularly during the eccentric phase, is a powerful stimulus for muscle growth. Blocking inherently reduces this stimulus.
• Improved Flexibility and Joint Health: Training through a full ROM also contributes to maintaining or improving joint flexibility and stability over time.

When "Blocking" Might Be Considered (and its Limitations)

While not optimal for hypertrophy, blocking might have specific, limited applications:

• Joint Protection/Rehabilitation: For individuals with pre-existing joint issues or during the rehabilitation process, a reduced ROM might be necessary to avoid pain or further injury. This is a therapeutic application, not a hypertrophy strategy.
• Specific Sport Performance: In some sports, movements might not require full joint articulation, and training a specific partial range could be sport-specific.
• Advanced Training Techniques (Periodization): Occasionally, partial repetitions or blocking might be used as a short-term variation in an advanced training program to overload a specific part of the strength curve, but this is usually integrated within a broader program that emphasizes full ROM.
• Targeting Peak Contraction (Debatable): Some lifters believe blocking allows for a more intense "peak contraction." While it can create a strong mind-muscle connection, the overall hypertrophic benefit is likely outweighed by the loss of full ROM.

Conclusion: Is Blocking Optimal for Size?

Based on current exercise science, "blocking" is not an optimal strategy for maximizing muscle hypertrophy (increasing size). While it can maintain constant tension and contribute to metabolic stress, the reduction in total range of motion significantly compromises the most potent stimuli for growth: high mechanical tension across the full muscle length and stretch-mediated hypertrophy.

For individuals whose primary goal is muscle size, prioritizing a full, controlled range of motion is paramount.

Practical Recommendations for Hypertrophy

To maximize muscle growth, focus on these principles:

• Full Range of Motion: Perform exercises through the greatest pain-free range of motion possible, ensuring the muscle is fully stretched and contracted.
• Progressive Overload: Consistently challenge your muscles by gradually increasing weight, repetitions, or training density over time.
• Controlled Tempo: Execute repetitions with a controlled pace, emphasizing the eccentric (lowering) phase to maximize mechanical tension and muscle damage.
• Mind-Muscle Connection: Focus on feeling the target muscle work throughout the entire movement.
• Adequate Volume and Intensity: Ensure your training program includes sufficient sets, reps, and intensity to stimulate growth.