When most people think about building muscle strength and size, stretching isn't usually the first thing that comes to mind. Traditional wisdom has long held that static stretching before strength training could actually decrease performance. However, recent research is challenging this notion and revealing some unexpected benefits of incorporating stretching into a strength and hypertrophy-focused training program. In this article, we'll explore the latest findings on how different types of stretching can impact muscle strength, size, and performance when integrated strategically with resistance training.
The Flexibility-Strength Connection
Flexibility and strength have often been viewed as separate or even opposing fitness components. However, studies are uncovering intriguing links between improved flexibility and enhanced strength performance. A systematic review by Afonso et al. (2021) found consistent evidence from multiple trials that eccentric training can improve both flexibility and strength in the lower limbs. The researchers noted that eccentric training appeared to be more effective than traditional static stretching for increasing muscle fascicle length and joint range of motion.
This connection between eccentric training, flexibility, and strength gains hints at the potential for certain types of stretching to positively influence muscle adaptation and performance. As we'll see, the type, duration, and timing of stretching can all impact its effects on strength and hypertrophy outcomes.
Static Stretching and Strength Performance
The longstanding advice to avoid static stretching before strength training was based on studies showing acute decreases in muscle force production following prolonged stretching protocols. However, more recent research suggests these negative effects may have been overstated.
A meta-analysis by Behm et al. (2021) found that short-duration static stretching (≤60 seconds per muscle group) had only trivial negative impacts on strength performance, with mean decreases of just 1-2%. Longer duration stretching of >60 seconds did show more substantial performance decreases of 4.0-7.5%. Importantly, when static stretching was performed as part of a full dynamic warm-up routine, even these small negative effects were eliminated.
These findings indicate that brief bouts of static stretching can likely be incorporated into a pre-workout routine without significantly compromising strength. For those concerned about even minor performance decreases, restricting static stretching to post-workout may be preferable.
Dynamic Stretching for Performance Enhancement
While static stretching has shown minimal negative (and some positive) effects on subsequent strength performance, dynamic stretching appears to offer more clear-cut benefits. Dynamic stretching involves moving through a joint's range of motion in a controlled, sport-specific manner.
Multiple studies have found that dynamic stretching can acutely enhance power, strength, and speed performance. For example, a study by Behm et al. (2011) observed that dynamic stretching improved subsequent countermovement jump height and muscle activation. The researchers theorized that dynamic stretching may enhance neuromuscular activation and muscle temperature, priming the body for explosive movements.
For strength athletes and bodybuilders, incorporating dynamic stretching into a warm-up routine could potentially boost performance in subsequent lifting. Movements like arm circles, leg swings, and torso twists that mimic the patterns of major lifts may be particularly beneficial.
Long-Term Stretching and Muscle Hypertrophy
Perhaps the most surprising recent findings relate to the long-term effects of stretching on muscle hypertrophy. While acute stretching has minimal impact on muscle size, consistent stretching over time may actually enhance muscle growth.
A groundbreaking study by Warneke et al. (2023) examined the effects of 6 weeks of daily static stretching on calf muscle size and strength. Participants stretched their calf muscles for one hour per day. Remarkably, this stretching-only protocol led to significant increases in muscle thickness, cross-sectional area, and strength comparable to traditional resistance training.
The researchers hypothesized that the long-duration stretching created sufficient mechanical tension to stimulate muscle protein synthesis and hypertrophy. This aligns with the principle that mechanical tension is a primary driver of muscle growth.
While an hour of daily static stretching may not be practical for most lifters, these findings suggest that dedicated stretching sessions could potentially complement traditional resistance training for maximizing hypertrophy. Even 10-15 minutes of post-workout stretching may provide a hypertrophic stimulus.
Flexibility Training for Injury Prevention
Beyond its direct effects on muscle strength and size, improved flexibility from regular stretching may indirectly benefit strength athletes by reducing injury risk. Greater flexibility allows for safer performance of exercises through a full range of motion.
A systematic review by Behm et al. (2016) found that pre-exercise static stretching reduced acute muscle strain injuries by 54%. The researchers concluded that 5-10 minutes of stretching as part of a full warm-up routine could significantly decrease injury rates in athletes.
For bodybuilders and powerlifters pushing their bodies to the limit, incorporating dedicated flexibility work may help prevent injuries that could derail training progress. This is especially relevant for muscle groups prone to tightness like the hip flexors, hamstrings, and chest.
Practical Recommendations
Based on the current body of research, here are some practical recommendations for incorporating stretching into a strength and hypertrophy-focused training program:
1. Include 5-10 minutes of dynamic stretching in your warm-up routine, focusing on movements that mimic your planned exercises.
2. If performing static stretching pre-workout, limit it to 30-60 seconds per muscle group to avoid potential performance decreases.
3. Add 10-15 minutes of static stretching post-workout, holding each stretch for 30-60 seconds. Focus on muscles worked that day.
4. Consider dedicated flexibility sessions 1-2 times per week, aiming for 20-30 minutes of total stretching time.
5. Experiment with longer-duration stretching (3-5 minutes per muscle group) on rest days to potentially enhance hypertrophy.
6. Pay extra attention to stretching chronically tight areas that may limit your range of motion on key lifts.
7. Gradually increase stretching intensity and duration over time to continue making flexibility gains.
Conclusion
While stretching alone is unlikely to build significant muscle, the latest research suggests it can play a valuable supporting role in a strength and hypertrophy program. From acute performance enhancement with dynamic stretching to potential long-term hypertrophic effects of static stretching, flexibility work offers more benefits than previously recognized.
By strategically incorporating different types of stretching before, during, and after resistance training, lifters may be able to enhance their performance, stimulate additional muscle growth, and reduce injury risk. As with any training variable, individual response may vary, so experiment to find the optimal stretching protocol for your goals and recovery needs.
Ultimately, stretching should be viewed as a complement to, not a replacement for, progressive resistance training. But for those looking to maximize their results, making time for regular flexibility work may provide that extra edge in building a stronger, more muscular physique.
References
1. Afonso, J., Ramirez-Campillo, R., Moscão, J., Rocha, T., Zacca, R., Martins, A., ... & Clemente, F. M. (2021). Strength Training versus Stretching for Improving Range of Motion: A Systematic Review and Meta-Analysis. Healthcare, 9(4), 427.
2. Behm, D. G., Blazevich, A. J., Kay, A. D., & McHugh, M. (2016). Acute effects of muscle stretching on physical performance, range of motion, and injury incidence in healthy active individuals: a systematic review. Applied physiology, nutrition, and metabolism, 41(1), 1-11.
3. Behm, D. G., Chaouachi, A. (2011). A review of the acute effects of static and dynamic stretching on performance. European journal of applied physiology, 111(11), 2633-2651.
4. Behm, D. G., Alizadeh, S., Anvar, S. H., Drury, B., Granacher, U., & Moran, J. (2021). Non-local acute stretching effects on strength performance in healthy young adults: A systematic review with meta-analysis. European Journal of Applied Physiology, 121(6), 1525-1537.
5. Warneke, K., Keiner, M., Wohlann, T., Lohmann, L. H., Schmitt, T., Hillebrecht, M., ... & Schiemann, S. (2023). Influence of long-lasting static stretching intervention on functional and morphological parameters in the plantar flexors: A randomized controlled trial. The Journal of Strength & Conditioning Research, 37(10), 1993-2001.