Is training at longer muscle lengths better for muscle growth?

Yes, studies indicate that training at longer muscle lengths appears to be more effective for promoting muscle hypertrophy than training at shorter muscle lengths. This could be due to mechanisms like stretch-mediated hypertrophy.

What is stretch-mediated hypertrophy?

Stretch-mediated hypertrophy is a hypothesis suggesting that combining an active contractile stimulus (like resistance training) with a stretch stimulus leads to greater muscle growth than the contractile stimulus alone. Training at longer muscle lengths may provide this combined stimulus.

Does the Warnicky study prove stretching causes muscle growth?

The Warnicky study is considered a 'proof of concept' study. While it showed significant calf growth from intense stretching, it used protocols much more rigorous than typical daily practice. It provides evidence supporting the potential for stretching to contribute to hypertrophy, especially in the context of stretch-mediated hypertrophy.

Should I stop lifting weights and only stretch for bigger muscles?

No, the research discussed does not suggest replacing resistance training with stretching for muscle growth. Instead, it explores how stretching might augment or contribute to hypertrophy, particularly when training at longer muscle lengths.

Why is training through a full range of motion better than partial reps?

Training through a full range of motion, especially at longer muscle lengths, has generally shown greater muscle growth compared to partial range of motion. This is likely because engaging muscles at their extended lengths provides a stronger stimulus for hypertrophy.

Can calf stretching help if my calves are hard to grow?

The Warnicky study demonstrated significant calf growth (15%) after 6 weeks of intense daily stretching. While this was a proof-of-concept study with a demanding protocol, it suggests individuals struggling with calf growth could potentially implement similar, though perhaps less extreme, stretching routines.

Key Moments

Can stretching directly cause muscle growth?

Stronger By Science

Sports3 min read31 min video

Sep 19, 2022|3,925 views|188|20

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Key Moments

TL;DR

Stretching may contribute to muscle growth, especially at longer muscle lengths, supporting the stretch-mediated hypertrophy hypothesis.

Key Insights

Full range of motion training generally leads to more muscle growth than partial range of motion training.

Training at longer muscle lengths appears to be a more significant factor for hypertrophy than the total range of motion itself.

Stretch-mediated hypertrophy is a leading hypothesis explaining why training at longer muscle lengths promotes growth.

A recent study using prolonged, intense calf stretching showed a significant increase in muscle thickness, supporting stretching as an independent hypertrophy stimulus.

This research helps solidify the theoretical and empirical basis for understanding how stretching might augment resistance training.

The findings could have implications for clinical populations undergoing bed rest, potentially aiding in muscle maintenance.

RANGE OF MOTION AND ITS IMPACT ON HYPERTROPHY

Historically, research has indicated that training through a full range of motion typically results in greater muscle growth compared to training with a partial range of motion. A foundational study by Bloomquist et al. compared quarter squats to parallel squats, finding significantly more quadriceps growth in the deeper squat group. This suggests that expanding the range of movement during resistance exercises is a key factor in maximizing muscle hypertrophy. Further studies aim to dissect whether the total range of motion or the specific muscle lengths trained are more influential.

MUSCLE LENGTH AS A KEY HYPERTROPHY DRIVER

More recent studies, such as one by Pedrosa et al., have helped to disambiguate the effects of range of motion versus muscle length. By comparing groups training at different knee flexion angles (long muscle lengths, short muscle lengths, and full range of motion), researchers found that training at longer muscle lengths consistently led to more muscle growth. This implies that the stimulus provided at the stretched end of a muscle's range is particularly conducive to hypertrophy, even more so than simply covering a larger total range of motion.

THE HYPOTHESIS OF STRETCH-MEDIATED HYPERTROPHY

The observation that training at longer muscle lengths yields greater hypertrophy has led to the hypothesis of stretch-mediated hypertrophy. This theory posits that combining an active contractile stimulus with a passive stretch stimulus results in enhanced intramuscular signaling, promoting more significant muscle growth than contractile stimulus alone. While a logical explanation, this hypothesis requires empirical evidence to confirm that stretching itself can independently stimulate hypertrophy in humans.

EMPIRICAL EVIDENCE FOR STRETCHING AND HYPERTROPHY

Early research in animals suggested that prolonged stretching could induce significant muscle hypertrophy and even hyperplasia. However, human evidence was less conclusive until a study by Simpson et al. showed a modest, though statistically significant, increase in calf thickness following a loaded calf stretching protocol. This provided some support but lacked the definitive impact that would firmly establish stretching as an independent hypertrophy stimulus.

A PROOF-OF-CONCEPT STUDY ON CALF GROWTH

A recent study by Warnicky et al. served as a proof-of-concept, employing an intensive and prolonged daily stretching regimen for six weeks. Participants stretched one calf for an hour each day to a significant discomfort level, while the other served as a control. This extreme protocol resulted in a notable 15% increase in calf muscle thickness in the stretched leg, compared to a mere 2% in the control leg. This was observed in recreationally trained individuals, suggesting that stretching can indeed be an independent driver of muscle growth.

IMPLICATIONS AND FUTURE DIRECTIONS

The findings from Warnicky et al. significantly bolster the stretch-mediated hypertrophy hypothesis, placing it on firmer theoretical and evidential ground. While not suggesting a replacement for resistance training, this research opens doors to potentially optimizing training strategies. Future research may explore whether partial range of motion training at longer muscle lengths, combined with stretching protocols, could surpass traditional full-range training for hypertrophy. Additionally, this research could be valuable for clinical populations, potentially helping to maintain muscle mass during periods of immobility.

Mentioned in This Episode

●Organizations

●Studies Cited

●People Referenced

Maximizing Muscle Growth: Key Insights

Practical takeaways from this episode

Do This

Train through a full range of motion, especially at longer muscle lengths, as this tends to promote more muscle growth.

Consider partial range of motion training at long muscle lengths, as it appears to be at least as effective as full range of motion for hypertrophy.

If struggling with calf growth, consider daily prolonged stretching (e.g., 1 hour per day for 6 weeks) as a potential, albeit demanding, intervention.

Explore the hypothesis of stretch-mediated hypertrophy, which suggests that combining active contraction with a stretch stimulus can enhance muscle growth.

For clinical populations unable to resistance train, intense stretching might help maintain muscle mass and strength.

Avoid This

Don't assume that stretching alone is more effective than resistance training for muscle growth.

Do not solely rely on short muscle length partial range of motion training if hypertrophy is the primary goal.

Avoid dismissing studies with intensive or unusual protocols (proof-of-concept studies) as they can provide valuable insights into mechanisms.

Don't assume stretch-mediated hypertrophy is fully proven; it remains a hypothesis supported by emerging evidence.

Comparison of Quadriceps Growth: Range of Motion vs. Muscle Length

Data extracted from this episode

Training Condition	Muscle Growth (Average % Increase)	Note
Full Range of Motion (Pedrosa et al.)	Increased growth at long muscle lengths	Effective, but potentially not superior to partials at long lengths.
Partial Range of Motion at Long Muscle Lengths (Pedrosa et al.)	Similar or slightly greater growth than full ROM	Suggests muscle length is key, not ROM per se.
Partial Range of Motion at Short Muscle Lengths (Pedrosa et al.)	Significantly less growth than long muscle lengths	Less effective for hypertrophy.
Deep Squats (Bloomquist et al.)	4-7% increase in quad CSA across most points	Greater growth than shallow squats.
Shallow Squats (Bloomquist et al.)	Some growth near hip, no/slight decrease near knee	Less effective overall than deep squats.

Calf Muscle Thickness Change: Stretching Intervention

Data extracted from this episode

Intervention	Change in Calf Muscle Thickness	Population
Loaded Calf Stretch (Simpson et al., 6 weeks, 3 min/day)	Slightly over 1 cm increase (statistically significant)	Not specified, but intervention was loaded.
Intense Calf Stretch (Warnicky et al., 6 weeks, 1 hour/day)	15% increase	Athletically active (>= 2 training sessions/week for 6 months)
Control Leg (Warnicky et al.)	2% increase	Athletically active (>= 2 training sessions/week for 6 months)

Common Questions

Emerging research, like the Warnicky study, suggests that prolonged, intense static stretching (e.g., 1 hour daily for 6 weeks) can lead to noticeable increases in muscle thickness, even in recreationally active individuals. This supports the idea that stretching itself might be an independent hypertrophy stimulus.

Topics

Static Stretching Calf Growth Proof Of Concept Studies

Mentioned in this video

People

Omar Esoph

Mentioned humorously as someone who might appreciate or be interested in implementing calf stretching for growth.

Studies & Research

Warnicky and colleagues

Authors of a recent study investigating the influence of long-lasting static stretching on muscle thickness, strength, and flexibility, focusing on calf growth.

Bloomquist and colleagues

Conducted a classic study comparing quarter squats versus parallel squats, finding greater quadriceps growth with deeper squats.

Pedrosa and colleagues

Authors of a study that helped disambiguate whether muscle length or total range of motion is more important for hypertrophy, using different knee extension protocols.

Simpson and colleagues

Conducted a study suggesting that stretching (loaded calf stretch) might lead to some hypertrophy, though the results were not considered a 'slam dunk'.

Sato and colleagues

Mentioned as having conducted studies similar to Pedrosa and colleagues, investigating range of motion effects on muscle growth.

Mayo and colleagues

Mentioned as having conducted studies similar to Pedrosa and colleagues, investigating range of motion effects on muscle growth.