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You’ve got your workout down to a tee and your post-training diet is at the peak of effectiveness - what else can aid in helping you quickly build up muscle as well as enhance your own flexibility, agility, and coordination? Why stretching, of course.

Physiology of Muscles

To understand stretching you must first start with the skeletal muscle system, beginning all the way deep down into the cells that comprise the muscles themselves. What exactly are your muscles made of? Beginning with the smallest component we find contractile proteins, mostly actin and myosin. Together, hundreds of molecules of these proteins form thick and thin myofilaments (protein strands). The thick and thin myofilaments overlap one another to create what is called the “sarcomere.” Literally millions of sarcomeres are laid end to end to create myofybrils, threads which can contract, relax, and lengthen themselves. Tens of thousands of myofybrils then compose muscle fibers which are bundled into fasciculi and finally grouped into fascicles, the tissue strands making up a muscle.

How exactly do these tiny muscle fibers, strands, threads and proteins operate together? As skeletal muscles are voluntarily moved and stretched with a single signal from your brain, it’s all about the message being sent. Your brain transmits a signal down your spinal column, through the neuromuscular junction, all the way into the muscle fibers themselves. The muscle is then cued to stimulate calcium flow to aid the movement of myofilaments and the shortening of the sarcomere. Your entire muscle will contract when billions of sarcomeres create a force by shortening all at once.

All around your muscles are protein fibers, collagenous connective tissue and elastic connective tissue, which make up the tendons, ligaments, and fascia that help stabilize joints and bind muscles into their own groups for movement. With more elastic connective tissue around your joints, you experience greater flexibility and range of motion.

How Do Muscle Groups Work Together When Stretching

Unlike Stretch Armstrong, when you extend your arm or flex your leg for a good stretch, it doesn’t just stay stretched forever, never returning to its original position. The body is cued with specifically designed reflexes and functions that help muscle groups stay intact and prevent injury. When you stretch, you have four muscle groups at work.

The prime movers, also known as agonists, are the muscles which generate the movement. Their counterparts, antagonists, act in opposition to that movement and are responsible for returning the limb to its original place. Neutralizers, or synergists, work in tandem with the prime movers to assist in generating their desired motion. And stabilizers, or fixators, simply work to make sure the rest of the muscle groups stay in place as the movement occurs. For example, when you stretch your calf muscle (prime mover), your shin acts in opposition (antagonist), relaxing and lengthening to allow for the calf stretch. (Check This Out: How to Perform Antagonist Paired Sets)

Physiologically, when you stretch the fibers in your muscle, the sarcomeres contract causing the myofilaments to overlap more and more, elongating the fiber until it can stretch no further. Once your muscle reaches that point, the connective tissues pick up the slack, helping realign any fibers that have become disorganized and releasing tension. All the while, nerve endings in the muscle fibers and the golgi tendon organ (a tendon near the end of the muscle fiber) are transmitting messages back to the central nervous system, relaying the change in length and how fast that is occurring.  The body’s myotatic reflex, or stretch reflex, is triggered, causing the muscle to contract. The more sudden the change in length of a muscle by stretching, the stronger the reflex to contract will be - like when you do plyometric squat, for example.

Isn’t the goal of stretching to lengthen and elongate muscles overtime to make them more limber and pliable? Well that’s where the next reflex enters. Autogenic inhibition follows the initial stretch reflex by cuing the muscle fibers to relax and lengthen once the tension on the connective golgi tendon organ has surpassed a certain threshold. It’s as if the message to contract gets drowned out eventually by the message to relax and lengthen. As mentioned above, when the prime mover contracts, the opposite muscle group (antagonist) relaxes to allow for the stretch - this reflect is called reciprocal inhibition.

How Does Stretching Build Muscle

There are two main categories of stretching - dynamic and static. Static stretching is your basic gym class stretching, in place, pulling and holding limbs without really moving. Dynamic stretching, on the other hand, involves more warm-up based movement, constantly in action stretching muscles. Good example of dynamic stretching include doing jump squats, burpees, or taking a brisk walk to warm muscles up.

After a hard workout or substantial weight lifting where you overload muscles with repetitive motions, even though your muscles are fatigued and exhausted, you look jacked right? Well at this point your muscle is sortof like a “pump” - it’s shortened, filled with by-products of exercise like lactic acid, and bulges more than normal. Static stretching after a training like this helps eliminate those built-up waste products from the muscle as well as return it to its normal range of motion, sort of reminding the muscle of its true length and fostering muscle growth.

Hardcore workouts essentially “damage” connective muscle tissues, and physiologists recommend static stretching post workout to help re-lengthen the muscles and prevent them from healing at a shorter length. By boosting your flexibility overtime through stretching, it is suggested that your own mechanical efficiency is heightened, helping you get more out of your workouts, extending your time to exhaustion, and allowing for more reps which build up more muscle. Not only that, but stretching naturally improves blood circulation to muscles - blood which carries with it oxygen and vital nutrients, and which helps flush out lactic acid that makes you feel more sore and tired.

Other Benefits of Stretching

In addition to building muscle, regular, smart stretching offers myriad physical benefits you will feel in your muscles and bones.

Increased Flexibility
Stretching boosts your functional flexibility, allowing you to achieve a greater range of motion with all your body parts. Limber, elastic muscles which are stretched and drawn out regular can even adapt and lengthen overtime, a function known as plasticity. Increased muscle flexibility means more room for muscles to grow.

Energy Boost
Stiff, tight muscles wrought with built-up lactic acid are soothed by the tension release of stretching. Not only can stretching boost your sense of alertness, but combined with mindfulness-cultivating practices like yoga or tai chi, it can aid concentration and focus as well.

Enhanced Performance
You understand how muscle groups work together and engage cohesively to power your movements and workouts. By boosting your flexibility and even fostering greater muscle growth, and therefore strength, stretching can enhance performance, helping you run and play faster with more agility and strength.

Improved Posture
When you’re not hitting the gym, are you finding yourself slouched over on the couch or slumping at your desk at work? Stretching induces natural spine lengthening and alignment, reinforcing back and shoulder muscles, and making you more body aware of your own posture.

Injury Prevention
While scientific studies have gone back and forth on the subject of injury prevention, stretching has been shown in some cases to aid stiff, tight muscles by loosening them up and making them more malleable and less likely to tear, strain, or sprain with sudden impact or force.

Relieves Pain
While soreness and aches which accompany muscle repair after a workout or game are normal, chronic pain that might be due to injury or added muscle inflammation is not. Gradual stretching techniques, like with yoga, can help alleviate low back pain, for example, by boosting blood circulation to swollen muscles, aiding tissue repair, and loosening joints.

Enhanced Oxygen Saturation
Did you know your diaphragm is a muscle which can be stretched and strengthened? Lance Armstrong famously had a resting heart rate of 32 beats per minute in the peak of his conditioning, largely because of his vast cardiovascular strength but also because of his enhanced respiratory system. Boosting your body’s ability to take in more oxygen both helps you fight fatigue when working out as well as extends your time to exhaustion when playing sports.

Stretching Reminders

Before you jump out of bed in the morning and start hitting the flexibility train, keep these important stretching tips in mind:

Stretch when muscles are warmed up. Typically after a workout or game, muscles are most pliable and ready for stretching. Pulling on stiff, tight muscles from the get go can result in unwanted strain and inflammation.

Hold static stretches for 30 seconds. Grabbing your ankle to pull your leg back and stretch your hamstring does little if you are doing fast, jolting movements and quickly switching legs. Stretches need to be held for at least 20 to 30 seconds to help your body override the reflex to contract (myotatic) and instead relax and lengthen with time.

Stretching tools can help. Foam rollers, resistance bands, and the top calf stretcher can aid your stretching routine, helping you target specific muscles in your back and calves for example.

Over-stretching can be harmful. If you overstretch muscles you can actually strain or tear them, resulting in injury which inhibits workouts and play, and therefore muscle growth. Never stretch through pain or injury, and always stretch when muscles are warmed-up and most malleable.

Introducing static stretching to your post-work routine could show increased flexibility and strength in a matter of a few weeks. Have you seen stretching pay off in your own life?

About The Author

Joe Fleming is the President at Interested in all things related to living a healthy lifestyle, he enjoys sharing and expressing his passion through writing. Working to motivate others and defeat aging stereotypes, Joe uses his writing to help all people overcome the obstacles of life. Covering topics that range from physical health, wellness, and aging all the way to social, news, and inspirational pieces...the goal is help others “rebel against age”.

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