What is stretch mediated hypertrophy and why it is not going to make you Hulk level massive

Summary

This video script discusses the misconceptions about stretch-mediated hypertrophy, emphasizing that muscle fibers must be active to experience tension for growth. It explains the biomechanics of leverage and activation during range of motion, the role of sarcomeres in passive tension, and the limitations of stretch-mediated adaptations over time. The speaker clarifies that while stretch exercises have their place, they do not inherently lead to greater hypertrophy compared to full range of motion exercises, and cautions about the potential for increased muscle damage from overstretching.

Takeaways

• 🏠 The speaker is in the process of moving into a new house and has been busy managing daily tasks.
• 🏋️ The speaker is about to head to the gym and decided to share insights on stretch-mediated hypertrophy.
• 📈 Stretch-mediated hypertrophy is often misunderstood and misrepresented on social media.
• 💡 For a muscle fiber to experience tension (active or passive), it must first be activated by an action potential from the motor cortex.
• 🧠 Muscle activation and the degree of activation depend on the internal leverage or moment arm at specific joint angles during a range of motion.
• 🔬 EMG (electromyography) can help identify which muscles are likely to grow with specific movements by measuring action potentials.
• ❌ The idea that 'everything grows better from a stretch' is a misconception; muscle leverage and activation play crucial roles.
• 🔍 Stretch-mediated hypertrophy involves the sarcomeres stretching to a length where Titan produces passive tension, leading to sarcomerogenesis.
• 📉 Over time, passive tension decreases as sarcomeres are added in series, which limits the duration and effectiveness of stretch-mediated hypertrophy.
• 🔄 Contraction-mediated hypertrophy produces myofibril genesis, which leads to radial growth or increased cross-sectional area of the muscle.

Q & A

What is the main topic discussed in the video?

The main topic discussed is stretch-mediated hypertrophy and its effects on muscle growth.

Why has the speaker not posted many videos recently?

The speaker has been busy moving into a new house and managing daily activities.

What is the primary misconception addressed about stretch-mediated hypertrophy?

The misconception is that everything grows better from stretch, which is untrue according to the speaker.

What is required for a muscle fiber to experience tension?

For a muscle fiber to experience tension, it must be active, meaning it has to receive an action potential from the motor cortex in the brain.

Why do lats have poor leverage in a lat pulldown when the arms are above 90 degrees?

Above 90 degrees, the lats have poor leverage because their internal moment arm is very short, resulting in low activation.

What role does EMG play in understanding muscle activation?

EMG measures action potentials and can help indicate which muscles are being activated during certain movements, although it doesn't predict hypertrophy outcomes.

Why might the lats not show significant activation during a dumbbell pullover?

During a dumbbell pullover, the motion primarily activates the pecs and triceps, with the lats having poor leverage and therefore low activation.

What is the difference between lengthening and stretching in the context of hypertrophy?

Lengthening refers to the muscle being extended, while stretching involves the sarcomere being stretched to a point where passive tension, particularly from Titan, is produced.

What adaptation occurs with stretch-mediated hypertrophy?

Stretch-mediated hypertrophy leads to sarcomerogenesis, where sarcomeres are added in series within the muscle fiber.

What evidence supports the occurrence of sarcomerogenesis?

Evidence includes changes in the angle of peak torque, which indicates that more sarcomeres are added in series, allowing force production at longer muscle lengths.

Why might the effects of stretch-mediated hypertrophy be limited over time?

Over time, as sarcomeres are added in series, the sarcomeres don't stretch as far individually, reducing passive tension and limiting further stretch-mediated hypertrophy.

How does the speaker suggest maintaining the adaptations from stretch-mediated hypertrophy?

The speaker suggests continuing to incorporate stretch or longer length motions to maintain the adaptations, while also minimizing them to avoid excessive fatigue and muscle damage.