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Quick takeaways
- Stretch mediated hypertrophy results in additional muscle growth when muscles are trained in a stretched position or experience passive tension.
- Active tension primarily leads to myofibrillar addition, while passive tension contributes to sarcomerogenesis.
- Muscle-specific response to stretch mediated hypertrophy is guided by the principle of neuro mechanical matching, where the nervous system allocates motor unit recruitment based on muscle leverage and length tension relationship.
- The capacity for stretch mediated hypertrophy is relatively quick but limited in duration, and the potential for further growth decreases once a muscle reaches its optimal length.
- Muscle growth is influenced by factors such as muscle activation, loading profiles, and neuro-mechanical matching, highlighting the importance of considering multiple factors in training programs for muscle development.
Deep dives
Stretch Mediated Hypertrophy: Understanding the Concept
Stretch mediated hypertrophy refers to the additional muscle growth that occurs when muscles are trained in a stretched position or when they experience passive tension. This type of hypertrophy is characterized by the addition of sarcomeres in series, which leads to an increase in muscle fiber length. However, it is important to note that not all muscles respond to stretch mediated hypertrophy in the same way. The extent to which a muscle can experience stretch mediated hypertrophy depends on factors such as the muscle's architecture and the length tension relationship. For example, muscles with better leverage and good length tension relationship in a stretched position tend to experience more stretch mediated hypertrophy. On the other hand, muscles with poor leverage and limited ability to be activated in a stretched position may not benefit as much from this type of hypertrophy.
Impact of Active and Passive Tension on Hypertrophy
The hypertrophy of muscles can be influenced by both active and passive tension. Active tension refers to the tension generated by the muscle through cross-bridge formation, while passive tension is produced by the stretching of the muscle without actin-myosin cross-bridges. When muscles are trained in moderate muscle lengths, active tension is the primary factor contributing to hypertrophy, leading to an increase in muscle fiber diameter. However, when passive tension is added to the equation through stretching or training in a stretched position, additional hypertrophy occurs in the form of the addition of sarcomeres in series. This indicates that different types of mechanical tension contribute to different types of hypertrophy. Active tension primarily leads to myofibrillar addition, while passive tension contributes to sarcomerogenesis.
Muscle-Specific Responses to Stretch Mediated Hypertrophy
Not all muscles exhibit the same response to stretch mediated hypertrophy. The response is specific to each muscle depending on its architecture and length tension relationship. Muscles with better leverage and good length tension relationship in a stretched position have a higher potential for stretch mediated hypertrophy. For example, the glute muscles show significant response to stretch mediated hypertrophy because they have good leverage in a stretched position, which allows for the addition of sarcomeres in series. However, muscles that lack leverage or the ability to be effectively activated in a stretched position may not experience significant stretch mediated hypertrophy. Muscle-specific responses to stretch mediated hypertrophy are guided by the principle of neuro mechanical matching, where the nervous system allocates motor unit recruitment based on the leverage and length tension relationship of each muscle.
Duration and Limitations of Stretch Mediated Hypertrophy
Stretch mediated hypertrophy occurs relatively quickly compared to other types of hypertrophy. However, its duration is limited. The rapid increase in fast-lying measurements associated with stretch mediated hypertrophy can be observed within a couple of weeks. However, over time, the hypertrophic response plateaus and the rate of growth decreases. This suggests that the capacity for stretch mediated hypertrophy is not sustained in the long term. Furthermore, the ability of a muscle to experience stretch mediated hypertrophy is influenced by its length tension relationship. Once a muscle reaches its optimal length for stretch mediated hypertrophy, it may no longer respond to further stretching or training in a stretched position. Therefore, the potential for stretch mediated hypertrophy is limited and specific to each muscle.
Study shows biceps growth from extended elbow position, not a longer muscle
A study from 1995 looked at the effects of training the biceps in an overhead position, which is often considered a stretch position. However, the study found that there was no increase in fascicle length after training the biceps in this position. This suggests that the biceps growth is not due to a longer muscle length but rather due to the activation in the stretch position. Another study from 2017 also supports this finding, showing that the biceps do not grow from longer muscle links. The study measured muscle thickness and found that the biceps did not experience an increase in fascicle length after training in a stretch position. Overall, these findings indicate that stretch-mediated hypertrophy may not be the primary mechanism for biceps growth.
Triceps growth is not solely influenced by a longer muscle
Research on triceps growth also challenges the notion that muscle growth is solely influenced by a longer muscle length. A 1995 study found that training the triceps in an overhead position did not lead to an increase in fascicle length. Similarly, a study from 2018 showed that training the triceps in a longer muscle length did not result in greater hypertrophy compared to training in an anatomical neutral position. These findings suggest that other factors, such as neuro-mechanical matching, may play a larger role in triceps growth. Further research is needed to fully understand the mechanisms behind triceps hypertrophy.
Study shows different triceps heads respond differently to different positions
A study from 2017 investigated triceps growth in different shoulder positions. The study found that the medial and lateral triceps heads showed greater hypertrophy in the overhead position, while the long head did not. This indicates that different regions of the triceps may respond differently to different positions and loading profiles. Another study from 2020 found that the triceps medial and lateral heads responded differently to training in a partial range of motion compared to the full range of motion. These findings suggest that triceps growth is not solely determined by muscle length, but also by factors such as muscle activation and loading profiles.
Overall, muscle growth is influenced by various factors beyond a longer muscle
In summary, the research on biceps and triceps growth challenges the notion that muscle growth is solely determined by a longer muscle length. Studies have shown that muscle growth is influenced by factors such as muscle activation, loading profiles, and neuro-mechanical matching. The position and range of motion used during training can impact muscle activation and leverage, leading to variations in hypertrophy across different muscle regions. Further research is needed to fully understand the complex mechanisms behind muscle growth. These findings highlight the importance of considering multiple factors beyond muscle length when designing training programs for muscle development.
Key Point 1: Muscle growth can be influenced by muscle length
Muscles like the abductors, hamstrings, quads, and glutes have been shown to benefit from stretch-mediated hypertrophy, meaning they are capable of growing better at longer muscle lengths. This is because they have a descending limb in their muscle architecture that allows for significant growth when loaded in a stretched position. However, it is important to note that not all muscles are the same, and certain muscles like the triceps do not experience stretch-mediated hypertrophy. Proper understanding of muscle architecture and lengthening capabilities is crucial when designing training programs for muscle growth.
Key Point 2: Importance of neuro-mechanical matching and muscle activation
Neuro-mechanical matching plays a significant role in muscle growth, especially in advanced individuals who have reached their muscular potential. The principle of matching exercise selection to muscle leverage and activation is vital for maximizing muscle growth. For example, exercises like glute bridges and hip thrusts have been found to activate and load the glutes effectively, leading to potential hypertrophy. Conversely, muscles like the anterior deltoids may not benefit significantly from stretch-mediated hypertrophy due to limited leverage and activation in stretched positions. Understanding muscle activation and leverage is essential for designing effective training programs for muscle growth.
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