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To Stretch or not to Stretch




IMG_9489Flexibility: To Stretch or Not to Stretch

The value of stretching should not be overlooked.

Sean Lee, NASM, ACE – CPT, NSCA – CSCS

Fitness Expert
Barrington, IL

KEY POINTS

  • Despite conflicting research and varying expert opinions regarding the benefits of stretching, the value of various flexibility applications to overall health and well being should not be overlooked.
  • Flexibility varies greatly from person to person and is influenced by genetics as well as internal and external factors.
  • Proprioceptive Neuromuscular Facilitation (PNF) is believed to be the most effective stretching technique for improving range of motion.
  • Integrating flexibility training as part of a balanced fitness program becomes increasingly important with age, injury, stress, and sedentary behavior.


INTRODUCTION

Stretching has become a hotly debated topic over the years. Although current research provides us with conflicting evidence regarding its benefits, the value of flexibility training as part of a balanced fitness program should not be ignored. Most experts well versed on the subject would agree flexibility plays an important role in general fitness. However, ask their thoughts on the benefits of stretching and it is likely you will get several different opinions, amidst conflicting beliefs and experiences based on the experts’ own interpretations and applications of current research. Muscle physiology is a complicated subject and often presents more questions than answers. For every answer there is another question, and for every question there are exceptions to the rules as we currently know them. Research may never uncover the absolute truth about stretching, but it is beginning to reveal that conventional methods of stretching may not be as beneficial as they were once thought to be.

FLEXIBILITY – STRETCHING – RANGE OF MOTION

It is important to differentiate between flexibility, stretching, and range of motion (ROM) as they are not one in the same. The term flexibility refers to the ability to move a single joint or series of joints through unrestricted pain-free motion. Stretching is a broad term used to describe any therapeutic maneuver designed to increase the extensibility of muscles and soft tissues. There are many progressive stretching techniques used to improve flexibility; stretching improves flexibility by lengthening structures that have become short, tight, and less mobile over time. Range of motion is simply the movement available around a joint. There are several factors that contribute to or limit joint motion. These include, but are not limited to the following:

FACTORS CONTRIBUTING TO JOINT MOTION

  • Muscle mass
  • Scar tissue
  • Bone shape
  • Inflammation and swelling
  • Body fat
  • The strength of opposing muscles
  • The length of muscles to be stretched
  • Neuromuscular inhibition

WHAT INFLUENCES FLEXIBILITY

Internal Influences
Flexibility is believed to be largely influenced by genetics, however there are a number of internal and external factors which also impact flexibility.

  • Hydration: dehydrated muscles are less pliable.
  • Scar Tissue: fibrous connective tissue with poor cir culation, pliability, and limited function.
  • Stress: increases muscular tension leading to poor circulation and postural stress.
  • Muscle Elasticity: the ability to lengthen a muscle or group of muscles.
  • Joint and Tissue Temperature: an increase in core body temperature decreases muscle viscosity, im- proves circulation and blood flow leading to improved flexibility.
  • Age: as we age our muscles and tissues begin to thicken and lose their elasticity.
  • Gender: females tend to be more flexible than males due to anatomical joint structure and hormonal profile.

External Influences

  • Temperature of Training Location: cool temperatures may limit flexibility.
  • Clothing Restrictions: tight clothing may restrict range of motion and inhibit flexibility.
  • Activity Level: Some research indicates that engaging in physical activity for 30 minutes or more on most days of the week can help maintain or improve flexibility in some people.
  • Occupation: sedentary occupations that require sitting for extended periods of time lead to muscle imbalances, postural stress, and reduced muscle and joint motion.
  • Time of Day: many people are less flexible in the morning.

WHY STRETCH

In therapeutic settings, evidence-based stretching techniques are used quite frequently and serve a specific purpose in the rehabilitation process leading to a patient’s functional outcome. However, in the fitness world, many people stretch recklessly, pulling and pushing on muscles and joints with no knowledge of what they are actually doing to their bodies. When asked why they stretch the way they do, the most common responses are:

  1. It warms me up
  2. It prevents or minimizes muscle soreness after workouts
  3. I do it to prevent injury
  4. It improves my performance
  5. It makes me more flexible
  6. It feels good

This begs the question, is conventional stretching beneficial for these reasons? Does it deliver the purported benefits people believe it does?

WHAT THE RESEARCH TELLS US

Stretching is not an effective method for warming up:
Compelling evidence says no to conventional static stretching techniques (holding stretches for 10-30 seconds) prior to sports participation or exercise. A recent study conducted at the University of Nevada, Las Vegas, showed that athletes who statically stretched their leg muscles prior to activity consistently generated less peak force than when not stretching at all. Neurologically, muscles become inhibited when statically stretched, making them weaker and less responsive, and potentially increasing the risk for injury.

Compelling evidence says no to conventional static stretching techniques (holding stretches for 10-30 seconds) prior to sports participation or exercise. A recent study conducted at the University of Nevada, Las Vegas, showed that athletes who statically stretched their leg muscles prior to activity consistently generated less peak force than when not stretching at all. Neurologically, muscles become inhibited when statically stretched, making them weaker and less responsive, and potentially increasing the risk for injury.

Stretching does not prevent or minimize DOMS (delayed onset muscle soreness)
Although it might feel good to stretch and there may be some physiological benefit of doing so, the evidence is clear that stretching does not prevent or minimize the effects of DOMS, the insidious muscle soreness often felt 24-72 hours after intense exercise.

Stretching may not prevent injury:
Each sport and activity places a unique set of demands on the human body, often under variable and sometimes inclement conditions making it difficult for researchers to come up with conclusive evidence regarding stretching and injury.

Several authors have reported stretching to have a beneficial effect on injury prevention, while clinical evidence has shown otherwise. At this time there is no scientifically based prescription for stretching and no conclusive statements can be made about the relationship between stretching and athletic injuries.

Stretching may or may not improve performance:
The idea that stretching may improve performance has been called into question by researchers, coaches, trainers, and athletes alike. There is a growing body of empirical research discounting conventional static stretching as a useful tool for improving performance. Several studies have reported as much as a 30% reduction in muscle strength after a bout of static stretching. Although tissue responses and adaptations to stretching have been studied at great length, there is considerably much less understood when highly complex skilled athletic motion is involved.

Stretching improved flexibility:
Sufficient evidence exists to support the use of various stretching techniques for improving flexibility. Currently, the most widely accepted form of stretching yielding the greatest benefits in terms of range of motion is Proprioceptive Neuromuscular Facilitation (PNF). In general, PNF describes the communication between the nervous and muscular systems. Essentially all stretching techniques are a component of PNF.  Common practice for athletes and exercise enthusiasts alike includes the use of one or more of the following:

  • Static Stretching – a method of stretching in which muscles and soft tissues are passively elongated to the point of light resistance and held for a period of 10-30 seconds. Currently the most controversial, debated and universally practiced stretching application.
  • Active Stretching – also referred to as static-active stretching. This technique utilizes agonist muscle contractions to move a joint or series of joints through a specific range of motion. For example, hamstring stretching while lying on your back – the hip flexing and quadriceps muscles (agoinst muscles) on the front side of the leg lift and stretch the hamstring muscles (opposing muscles) on the backside of the leg.
  • Dynamic Stretching – uses the internal force of a muscle and the body’s momentum to take a joint through a full range of functional movement patterns. Dynamic stretching is the only form of stretching recommended before exercise after a general warm-up.
  • Resistance Stretching – a technique in which a muscle or group of muscles simultaneously contracts and elongates. Recently popularized by the 41-year-old Olympic swimming medalist Dara Torres

BENEFITS OF STRETCHING

Most people could benefit from some form of stretching. It is clear that flexibility and the use of stretching to improve range of motion become increasingly important with age, injury, stress, sedentary behavior, or any combination of these factors. Integrating flexibility exercises four or more days per week has been shown to yield the following benefits for these populations:

  • Increases muscle elasticity
  • Improves joint integrity and range of motion
  • Improves posture
  • Decreases the risk of muscle imbalances and joint dysfunction.
  • Reduces the risk of low back pain
  • Increases blood supply and the delivery of nutrients to muscles, tissues, and joints.
  • Improves neuromuscular coordination (muscle coordination and control)
  • Decreases muscle tension
  • Improves muscle length-tension relationships (optimal muscle length and tension to produce force)
  • Improves the ability to perform activities of daily living

CONCLUSION

There are no definitive answers to the ongoing stretching debate. Much of the research pertains to the old ideals of static stretching as it relates to warm-ups, injury prevention, and enhancing performance. It is now considered best practice to actively warm-up in preparation for exercise or athletic activity as this may also assist in the prevention of injury and boost performance. So that old elementary school gym class static warm-up may not be your best option. Science has since moved on and proven other methods of warming-up to be superior.

REFERENCES

1. Andersen, J. C. Stretching Before and After Exercise: Effect on Muscle Soreness and Injury Risk. Journal of Athletic Training 40(2005): 218-220

2. Kisner, Carolyn, Colby Lynn: Therapeutic Exercise 5th Edition: Foundations & Techniques (2007)

3. Witvrouw, Erik, Nele Mahieu, Lieven Danneels, and Peter McNair. Stretching and Injury Prevention An Obscure Relationship. Sports Medicine 34.7(2004): 443-449

This article may be reproduced for non-profit, educational purposes only. For additional information go to: WWW.GOMOJI.COM 2009 Moji

Content is provided for informational purposes only and is not a substitute for professional advice. You should consult a physician in all matters relating to your health, and particularly in respect to any symptoms that may require diagnosis or medical attention



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