Scientists weigh in on the optimal dose for its benefits
To stretch, or not to stretch—that is the question that has puzzled exercisers, athletes, coaches, and researchers alike for decades. Static stretching, the act of holding a muscle at its end range of motion for extended periods, has been both celebrated and vilified. Once considered an essential part of any fitness routine, it is now frequently questioned for its actual benefits. Does it prevent injuries? Improve performance? Or is it merely a time-consuming habit with little tangible reward?
A recent review published in Sports Medicine offers long-overdue clarity on its efficacy. Analyzing 189 studies with data from over 6,600 participants, the review provides evidence-based guidelines on how much—and how little—stretching is necessary to improve flexibility. The findings reveal a straightforward conclusion: to achieve meaningful results, 4 minutes per muscle group per session is optimal for short-term gains, while 10 minutes per muscle group per week is sufficient for long-term improvements.
Stretching beyond these thresholds, the authors note, adds little to no additional benefit, underscoring the importance of quality over quantity. This revelation challenges the traditional perception of stretching as a necessary cornerstone of fitness and instead positions it as a focused tool for specific outcomes.
Stretching Science
For decades, static stretching was the fitness world’s Swiss army knife—purportedly useful for everything from injury prevention to performance enhancement. However, as more research has emerged, many of these claims have come under scrutiny. The Sports Medicine review divides the effects of static stretching into two categories: acute, which refers to immediate but temporary flexibility improvements, and chronic, which encompasses longer-term adaptations over weeks or months.
The review found that a single stretching session, when performed correctly, leads to moderate, measurable improvements in flexibility. Specifically, 4 minutes of stretching per muscle group per session was shown to maximize short-term range-of-motion gains. This is good news for those who want immediate results without committing to marathon stretching routines. Whether you’re preparing for a yoga class or aiming for better form in a weightlifting session, a few minutes of targeted stretching can make a difference.
For those seeking more permanent flexibility improvements, the review recommends a cumulative approach: 10 minutes of stretching per muscle group per week, spread across multiple sessions. Unlike acute benefits, which are fleeting, this approach creates lasting changes in muscle and tendon structure. Interestingly, the frequency of sessions matters less than the total weekly time spent stretching, giving athletes and casual exercisers alike flexibility in how they structure their routines.
(Photos: Sports Medicine)
Debunking the Myths
Despite its well-documented effects on flexibility, static stretching is often misunderstood as a panacea for other fitness goals. Let’s explore some of the myths surrounding its broader benefits.
One of the most persistent beliefs is that stretching reduces the risk of injury. The evidence, however, tells a more nuanced story. While stretching can improve flexibility and address muscle imbalances—factors that may reduce strain in some individuals—it does not universally prevent injuries. Most injuries stem from overuse, poor biomechanics, or sudden impacts, none of which are directly mitigated by improved flexibility alone. In some cases, excessive flexibility may even be counterproductive. Overstretched muscles can lose stability, increasing the likelihood of joint injuries in activities requiring precision and strength. This finding underscores the importance of balancing flexibility with strength and stability.
The relationship between stretching and athletic performance is similarly complex. Sports like gymnastics, dance, or martial arts—where a wide range of motion is essential—undoubtedly benefit from regular stretching. For runners, however, greater flexibility may reduce running economy by weakening the “spring-like” tension in their tendons. This suggests that the benefits of stretching depend heavily on the specific demands of your sport or activity.
The Science of Smarter Stretching
The Sports Medicine review offers clear, actionable insights for incorporating stretching into fitness routines without overdoing it. Here are the key takeaways:
- 4 minutes per muscle group per session: For immediate flexibility gains, a total of 4 minutes of stretching per muscle group per session is sufficient. This can be achieved through multiple short holds (e.g., 4 stretches of 1 minute each) or a single sustained stretch.
- 10 minutes weekly: For long-term improvements, aim for 10 minutes per muscle group per week. This can be split across as many or as few sessions as you prefer, making it easy to integrate into your schedule.
- Target problem areas: Stretching is most effective for individuals with poor baseline flexibility. Focus on tight or overused muscle groups, such as hamstrings, hip flexors, and calves.
- Stretch when warm: Static stretching is most effective when performed after a workout, once muscles are warm and pliable. For pre-workout preparation, dynamic stretching or movement-based warm-ups are better options.
Strength as a Flexibility Tool
One of the more surprising insights from the review is the growing evidence supporting strength training as an alternative—or complement—to static stretching. Exercises like squats, lunges, and Romanian deadlifts, when performed through a full range of motion, can improve flexibility while simultaneously building muscle strength and stability. This dual benefit makes strength training an appealing option for those who feel stretched thin (bad pun) by their fitness routines. Not only can it improve mobility, but it also addresses the strength imbalances that often underlie poor flexibility.
The findings offer a refreshingly simple message: stretching, when done strategically, is a powerful tool for improving flexibility. However, its benefits do not extend universally to injury prevention or performance enhancement. For many, a balanced routine that includes strength training, dynamic warm-ups, and targeted stretching will yield the best results.
Ultimately, whether you stretch—or how much you stretch—depends on your individual goals. For those whose activities and sports demand flexibility, stretching is non-negotiable. For runners and other endurance athletes, focusing on strength and mobility may be more impactful. And for those seeking efficiency, a few well-placed minutes of stretching each week are all it takes to maintain a healthy range of motion.
So, to stretch or not to stretch? The answer lies not in dogma but in the science—and a little self-reflection about what you’re trying to achieve.