To Stretch or Not To Stretch?
That is the question. Some experts say no, some say yes. Should you stretch before a workout? Should you stretch after a workout? Is stretching really that important? It’s confusing out there on the world-wide web. This post will focus on some pretty great research in the stretching department as it relates to muscle strength.
Most of us love to stretch. We don’t really think about it, but when we wake up in the morning we lift our arms overhead to lengthen our body after a night’s sleep. After sitting for a while, we stand up and side bend both ways to stretch out our back. And after a moderate walk, we may stretch our quadriceps (thigh muscle) to alleviate any stiffness. Stretching is a natural, functional human instinct. However, there is some controversy about stretching when combined with exercise.
What is stretching?
Some of you may think this is a silly question to address, but stretching is misunderstood. Stretching is the act of lengthening a muscle in order to increase the range of motion or flexibility around a joint. It should feel uncomfortably tolerable. It should not be painful. The cue I give my patients: “Stretching should feel like muscle lengthening, not ripping”.
Common types of stretching
- Static (passive): this is the most common type of stretching. It involves holding the muscle in one position for 30-60 seconds. This type of stretching is the focus of this blog.
- Eccentric: this is becoming more popular with athletic populations. It entails contraction of the muscle while it is being stretched. It usually requires a partner.
- Proprioceptive Neuromuscular Facilitation (PNF): there are several types of PNF stretches and it uses the concept of antagonist (ie. hamstring) and agonist (quadriceps) muscle relationships. That’s another post for another time.
Ok, so now let’s dive into static stretching a bit more. Because it is the most familiar type, this is what we think of when someone mentions stretching. Imagine someone about to go on a run. They pull their heel up toward their glute and hold a quad stretch. Maybe they bend over to touch their toes in order to stretch their back and hamstrings. We’ve all seen it…we still see it. But, is static stretching appropriate before a workout? “Survey Says:” NO.
Over the past decade, researchers have found that static stretching inhibits muscle activity and maximal force output. This isn’t just one research article, but many! And, the research has also found a “dose-response” of static stretching on muscle strength; the more repeated static stretches performed, the less the muscle wants to exert force. Why does static stretching decrease muscle activation? Here are some theories in the works:
- Decreased blood flow to the muscle
- Increased Ca++ (calcium) levels in the cells, which decreases motor neuron excitability
If you’re a static stretcher before you exercise, you may be thinking: “Yikes! Just how strong could I be if I didn’t stretch!”. Then, you might ask yourself: “Well what do I do before a workout if I’m not supposed to stretch?”
A dynamic warm-up. This can be a variety of movements from single leg squats, to walking up and down the stairs, to busting out a few clams and fire hydrants (a link to a previous post about these exercises). The warm-up just depends on the activity. Think of Michael Phelps at the Olympics. Before he swims, what does he do? He swings his arms every which way in order to prepare his muscle tissue before the event. That’s a specific dynamic warm-up for swimming, but you get the idea. A dynamic warm-up is meant to bring blood flow, heat and proprioception (body awareness) to the muscles about to be stressed. And, we know from research that it DOES NOT inhibit muscle strength.
Back to the question. Is static stretching ever a good thing to do? YES! Static stretching is very important, just do it after a workout and on rest days. And, don’t over-stretch. In 2010, Kokkonen et al studied two groups. Group 1 performed weight training 3x/week for 8 weeks, performing 3 sets of 6 repetitions (6 repetitions means these people were lifting some heavy weight!). Group 2 did the same lifting routine as group 1 but added static stretching 2x/week for 30 minutes. Guess who had the better strength results at the end of the 8 weeks? Group 2. So, although static stretching inhibits muscle strength before a workout, it helps with long-term strength gains. What? Wait. Whoa. How does static stretching help gain overall strength if it inhibits muscle activity?
Let’s back up. The acute or immediate response of muscle tissue after static stretching is muscle inhibition. But, static stretching after a workout and on rest days is powerful because it aids in recovery from post-exercise muscle stiffness and establishes the optimal length-tension of a muscle.
A professor in graduate school used to say: “A short muscle is a weak muscle”. At first, this seems counter-intuitive, but it is a true statement. Short muscle is weak muscle. And, long muscle is weak muscle. In general, every muscle has an optimal length in order to produce the most force. This length may vary depending on the activity (ballet vs. football), but for the mass population: every muscle has an optimal length for optimal strength.
Length-tension relationship of muscle
Without getting too technical, muscle cells are composed of actin and myosin. Actin filaments are thin and myosin filaments are thick. Together, these two filaments over-lap and form cross-bridges. These cross-bridges are what give muscle the ability to contract and generate force. If the cross-bridges are too close together (short muscle) or too far apart (long muscle), the force production is decreased. Research shows an optimal sarcomere length of 2-2.25 micrometers. Now, you’re not going to go out and find a micrometer to measure your sarcomere length (impossible, really), but the point is this: Stretching allows for muscle to activate in its optimal range of motion.
- You need a dynamic warm-up before a workout
- Use static stretching after a workout and on rest days
- If you’re not stretching, your muscles are likely not as strong as they could be
Thank you for reading! If you enjoyed this post, please share so others can learn too.
© 2014 and Beyond. ALL BLOG CONTENT at duncansportspt.com by Lori Duncan PT
ABOUT THE AUTHOR
Lori Duncan, DPT, MTC, CPT is a respected Physical Therapist, Manual Therapist and Pilates instructor in Lafayette, CO. Lori is passionate about preventive physical therapy and education and is a nationally recognized presenter. She can be reached at [email protected] You can also follow Duncan Sports Therapy + Wellness on Facebook & Instagram for more free tips and information.
Kokkonen J, Nelson AG, Tarawhiti T, Bukcingham P, Winshester JB. Early-phase resitance training strength gains in novice lifters are enhanced by doing static stretching. J Strength Cond Res. 2010;24(2):502-6
Torres R, Pinho F, Duarte JA, Cabri JM. Effect of single bout versus repeated bouts of stretching on muscle recovery following eccentric exercise. J Sci Med Sport. 2013;16(6):583-8
Winchester JB, Nelson AG, Kokkonen J. A single 30-s stretch is sufficient to inhibit maximal voluntary strength. Res Q Exerc Sport. 2009;80(2):257-261
Winchester JB, Nelson AG, Landin D, Young MA, Schexnayder IC. Static stretching impairs sprint performance in collegiate track and field athletes. J Strength Cond Res. 2008;22(1):13-9