Stretching for Hypertrophy: Fact or Fiction Summary
- Studies suggest that longer stretching durations (i.e., 60 minutes) may effectively induce hypertrophy. High volumes of stretching and longer intervention periods may be more likely to result in hypertrophy and strength increases.
- The intensity of muscle stretch plays a crucial role in adaptations; stretching must be intense with a pain scale of 8-10 to induce muscle hypertrophy.
Is the Stretch Good for Muscle Growth?
The concept of stretching for hypertrophy has gained traction in recent years. There is a significant body of literature on skeletal muscle hypertrophy in response to resistance exercise(Wackerhage et al., 2019). This involves using resistance machines and devices to induce mechanical tension, a crucial factor that stimulates the pathways enhancing protein synthesis. However, recent studies brings to light findings from animal and human research that suggest another potential method: long duration, frequent stretching. (Nunes et al., 2020). Much debate exists about the relationship between stretching the muscle and muscle growth (i.e., muscle hypertrophy).
There has been some confusion in which people think that just short stretching without tension on the muscle leads to muscle growth. Many factors influence muscle hypertrophy, including muscle tension, nutrition, and exercise. Under certain circumstances, stretching the muscle can lead to muscle growth. However, the findings considered are biased by the different methods applied in the literature, particularly regarding stretching intensity and duration. This article debunks this myth by synthesizing and analyzing relevant scientific literature on stretch for muscle hypertrophy.
Stretching and Stretch Mediated Hypertrophy
Stretch mediated hypertrophy and increased muscle thickness have been observed in studies focusing on the impact of stretching on muscle growth. The relationship between stretching and muscle growth has been a topic of interest in muscle physiology. Stretch-mediated hypertrophy refers to the potential muscle growth achieved through various stretching techniques.
Stretch mediated hypertrophy and increased muscle thickness occur in both human and animal studies focusing on the impact of stretching on muscle growth. (K. Warneke et al., 2022; Yahata et al., 2021) The idea that stretching can lead to muscle growth is not new. They have been doing animal stretch studies as early as the 1970s. (Tabary et al., 1972)
Different types of stretching, such as static and dynamic stretching, may have varying effects on muscle growth. By stretching muscles for a prolonged position, it is believed that a deeper stretch can lead to greater muscle activation and potentially improved muscle growth.
Animal Studies on Muscle Stretch and Hypertrophy
Animal studies have played a crucial role in exploring the effects of stretching on muscle hypertrophy. Findings from these animal experiments have shown that stretching at extended muscle lengths can lead to an increase in muscle growth and maximal strength. However, it is important to note that the results from animal studies may not directly translate to humans due to differences in physiology. Despite the limitations, these animal studies provide potential implications for human stretching protocols, highlighting the importance of incorporating a full range of motion and stretching to achieve optimal hypertrophy.
The Impact of Long Duration Stretching in Animals
Animal research has been instrumental in understanding stretching for hypertrophy. Studies have been conducted to analyze the effects of long-duration stretching on muscle growth.(Konstantin Warneke et al., 2022) These experiments explored how prolonged stretch affects muscle hypertrophy in animals. Researchers commonly use a method involving stretching one wing muscle in chickens or quails. This is accomplished either by using a stretching device or attaching a weight to the wing equivalent to 10-35% of the bird’s bodyweight. (Barnett et al., 1980; Bates, 1993; Sola et al., 1973). Animal studies have shown that stretching can activate growth factors and anabolic pathways, leading to muscle growth. These adaptations result in gene expression, muscle protein synthesis, and fiber cross-sectional area changes.(Warneke, Lohmann, et al., 2023)
However, it is important to note that the results from animal studies may not directly translate to humans due to differences in physiology. Most of these studies used a model in which the muscle was stretched continuously for 24 hours daily, which is unrealistic for human studies. Human studies can’t compare to animal stretch mediated muscle growth models. Despite the limitations, these animal studies provide potential implications for human stretching protocols, highlighting the importance of incorporating a full range of motion and stretching to achieve optimal hypertrophy. While animal studies consistently reported muscle hypertrophy in response to stretching, human studies showed contrasting results.
The Human Angle: Stretching for More than an Hour
The relationship between muscle stretch and muscle growth, specifically stretching for hypertrophy, has been a topic of debate. Researchers have investigated the impact of stretching and muscle hypertrophy by exploring the effects of prolonged stretching in humans. (Nunes et al., 2020) Interestingly, this study found that passive, low-intensity stretching (i.e., 4.5 minutes to 36 minutes per week) does not lead to muscle growth. However, limited evidence suggests that stretching with certain muscle tension (i.e., weight stretching) may elicit muscle hypertrophy.
Most short-duration calf stretching (< 60 minutes) studies have not shown an effect on muscle hypertrophy. However, one study found stretching durations of up to 15 minutes, 5 days per week, in adolescent female volleyball players. They reported a significant increase in muscle hypertrophy of approximately 23% in the intervened leg and around 13% in the control leg.(Panidi et al., 2021)
Research on long-duration stretching, high-frequency stretching (i.e., > 1 hour), and muscle growth has shown extended stretching duration’s potential benefits. (Warneke, Wirth, et al., 2023) Interestingly, this study found that 1 hour a day of stretching (i.e., 7 hours of continuous, painful stretching per week) resulted in similar calf muscle growth as 45 minutes of total calf training per week (three days of 5 sets of 10-12 reps to failure). They found significant hypertrophy with enhancements in muscle thickness ranging from approximately 5% to 15%. Overall, the human angle of stretching for more than an hour offers intriguing insights into the physiology of muscle growth and the effects of stretched positions.
Pain Scale and Its Relevance in Stretching Exercises
Understanding and appropriately assessing pain during stretching exercises is crucial for optimizing muscle hypertrophy outcomes. Incorporating a pain scale can help individuals gauge their discomfort levels and adjust their routines accordingly. Pain perception plays a significant role in determining the intensity of muscle contraction and the range of motion achieved during stretches. The intensity of the stretching for hypertrophy is pivotal; stretching for hypertrophy should be intense, registering 8-10 on a pain scale.
In-depth Analysis of Recent Research on Stretching for Hypertrophy
A recent review by Warneke et al. put together a comprehensive review of the literature titled “Physiology of Stretch‑Mediated Hypertrophy and Strength Increases: A Narrative Review,” published in the journal “Sports Medicine” on stretching for hypertrophy. The authors discuss the role of various factors, including mechanical tension, muscle protein synthesis, and signaling pathways, in promoting muscle growth and adaptation.
In human studies, the effects of stretching on muscle hypertrophy have been less consistent. Some studies have reported increases in muscle cross-sectional area, while others have shown no significant changes. The duration and volume of stretching interventions, as well as individual factors such as sex and training status, may influence the outcomes. For example, women who stretched gained less muscle mass than men. This may be due to men being less flexible and having more of a stretch-induced muscle hypertrophy response than women.(Warneke, Lohmann, et al., 2023)
Stretching is renowned for enhancing flexibility, while resistance training is the go-to for strength and hypertrophy. Both methods induce mechanical tension, a crucial factor for stimulating anabolic signaling and protein synthesis. Current research indicates the potential of high-frequency, prolonged stretching to boost muscle volume in humans. However, lifters can get the same amount of muscle growth in the gym with stretch related exercises with tension. There’s a need for standardization in the methods used across studies, especially concerning stretching intensity and duration for stretch mediated hypertrophy studies. The inconsistent results in human studies highlight the need for more research on stretching for hypertrophy.
To sum it up, stretching plays a role in muscle hypertrophy, but it is not the sole factor. Human studies have shown mixed results for stretch mediated hypertrophy, with long-duration stretching having more impact than short-duration stretching. Recent research has provided insights into the importance of specific muscle groups and the need to consider factors like pain scale in stretching exercises. In the realm of muscle growth, stretching for hypertrophy has emerged as a topic of interest. While it plays a role, it should be combined with other techniques for optimal results. As research continues, the potential of stretching for hypertrophy becomes clearer, offering a new perspective on muscle growth techniques.
While stretching is essential for muscle growth, it should be combined with other techniques like resistance training for optimal results. It is important to address myths surrounding stretching and understand its limitations. So, while stretching can contribute to muscle hypertrophy, it should be part of a comprehensive approach that includes proper nutrition, rest, and other muscle growth techniques.
Barnett, J. G., Holly, R. G., & Ashmore, C. R. (1980). Stretch-induced growth in chicken wing muscles: biochemical and morphological characterization. American Journal of Physiology-Cell Physiology, 239(1), C39-C46. https://doi.org/10.1152/ajpcell.1980.239.1.C39
Bates, G. P. (1993). The relationship between duration of stimulus per day and the extent of hypertrophy of slow-tonic skeletal muscle in the fowl, Gallus gallus. Comp Biochem Physiol Comp Physiol, 106(4), 755-758. https://doi.org/10.1016/0300-9629(93)90393-i
Nunes, J. P., Schoenfeld, B. J., Nakamura, M., Ribeiro, A. S., Cunha, P. M., & Cyrino, E. S. (2020). Does stretch training induce muscle hypertrophy in humans? A review of the literature. Clin Physiol Funct Imaging, 40(3), 148-156. https://doi.org/10.1111/cpf.12622
Panidi, I., Bogdanis, G. C., Terzis, G., Donti, A., Konrad, A., Gaspari, V., & Donti, O. (2021). Muscle Architectural and Functional Adaptations Following 12-Weeks of Stretching in Adolescent Female Athletes [Original Research]. Frontiers in Physiology, 12. https://doi.org/10.3389/fphys.2021.701338
Sola, O. M., Christensen, D. L., & Martin, A. W. (1973). Hypertrophy and hyperplasia of adult chicken anterior latissimus dorsi muscles following stretch with and without denervation. Exp Neurol, 41(1), 76-100. https://doi.org/10.1016/0014-4886(73)90182-9
Tabary, J. C., Tabary, C., Tardieu, C., Tardieu, G., & Goldspink, G. (1972). Physiological and structural changes in the cat’s soleus muscle due to immobilization at different lengths by plaster casts. J Physiol, 224(1), 231-244. https://doi.org/10.1113/jphysiol.1972.sp009891
Wackerhage, H., Schöenfeld, B. J., Hamilton, D. L., Lehti, M., & Hulmi, J. J. (2019). Stimuli and Sensors That Initiate Skeletal Muscle Hypertrophy Following Resistance Exercise. Journal of Applied Physiology. https://doi.org/10.1152/japplphysiol.00685.2018
Warneke, K., Freund, P. A., & Schiemann, S. (2022). Long-Lasting Stretching Induces Muscle Hypertrophy: A Meta-Analysis of Animal Studies. Journal of Science in Sport and Exercise. https://doi.org/10.1007/s42978-022-00191-z
Warneke, K., Lohmann, L. H., Keiner, M., Wagner, C. M., Schmidt, T., Wirth, K., Zech, A., Schiemann, S., & Behm, D. (2022). Using Long-Duration Static Stretch Training to Counteract Strength and Flexibility Deficits in Moderately Trained Participants. Int J Environ Res Public Health, 19(20). https://doi.org/10.3390/ijerph192013254
Warneke, K., Lohmann, L. H., Lima, C. D., Hollander, K., Konrad, A., Zech, A., Nakamura, M., Wirth, K., Keiner, M., & Behm, D. G. (2023). Physiology of Stretch-Mediated Hypertrophy and Strength Increases: A Narrative Review. Sports Med. https://doi.org/10.1007/s40279-023-01898-x
Warneke, K., Wirth, K., Keiner, M., Lohmann, L. H., Hillebrecht, M., Brinkmann, A., Wohlann, T., & Schiemann, S. (2023). Comparison of the effects of long-lasting static stretching and hypertrophy training on maximal strength, muscle thickness and flexibility in the plantar flexors. Eur J Appl Physiol, 123(8), 1773-1787. https://doi.org/10.1007/s00421-023-05184-6
Yahata, K., Konrad, A., Sato, S., Kiyono, R., Yoshida, R., Fukaya, T., Nunes, J. P., & Nakamura, M. (2021). Effects of a high-volume static stretching programme on plantar-flexor muscle strength and architecture. Eur J Appl Physiol, 121(4), 1159-1166. https://doi.org/10.1007/s00421-021-04608-5
In the recent systematic review examining stretching’s impact on muscle size and mobility, stretch-mediated bodybuilding exercises like calf raises, biceps curls, preacher curls, triceps extensions, and flyes were compared to a control group emphasizing long-muscle length exercises. The studies found either similar or greater muscle growth with longer muscle lengths. While exercises like the biceps curl and triceps extension are staples in bodybuilding, future research should delve deeper into their effects on the hamstrings, lats, and other muscles to ensure optimal gains without undue harm.
Can stretching really help with muscle growth and hypertrophy?
While stretching is important for maintaining flexibility and preventing injuries, it does not directly contribute to muscle growth or hypertrophy. To maximize muscle growth, focus on resistance training exercises that target specific muscle groups and follow a balanced diet rich in protein and nutrients.