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Status:Closed    Asked:Nov 10, 2012 - 11:53 AM

Why stretch before cardio warm-up and not after?

Can someone explain the scientific rationale behind why NASM recommends stretching before the 5-10 minute cardio warm-up? In my experience, it is better to have an elevated heart rate, increased body temp. and perspiration, and increased blood flow to the extremities, etc. before stretching to minimize risks of straining/pulling a muscle. So common sense tells me to do the cardio warm-up and then stretch.


Thanks!

 
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Answers

Remember we are only performing static and active flexibility techniques on short/overactive muscles vs. just any muscle. Many times in research studies they are just stretching everything even if it has not been identified as needing to be lengthened. We are recommending targeted stretching based off an assessment.

Here is a recent review done on stretching.


To Stretch or Not Prior to Exercise? A systematic review of the effects of acute static stretching on maximal muscle performance


January 23, 2012 Darin A. Padua, PhD, ATC


Kay AD, Blazevich AJ. Effect of Acute Static Stretching on Maximal Muscle Performance: A Systematic Review. Medicine and Science in Sports and Exercise 44(1): 154-164, 2012.

PMID: 21975448


RATIONALE & PURPOSE: There is currently a significant amount of controversy surrounding the issue of performing static stretching prior to exercise. Sports medicine professionals have often recommended that static stretching be performed prior to exercise as part of a comprehensive warm-up to help facilitate proper muscle length / balance and ready the body for physical activity. However, more recent research has shown that static stretching can negatively maximal force production when performed immediately prior to exercise. As a result, there has been a recent trend for sports medicine professionals to recommend eliminating static stretching from pre-exercise warm up routines for fear that performing static stretching pre-exercise may reduce physical performance of individuals. Inspection of studies investigating the effects of static stretching on physical performance measures reveals that a wide range of static stretching protocols and physical performance tests have been used across studies. As such, it is not entirely clear how certain aspects of static stretching (e.g. duration of stretch) may affect different physical performance measures (e.g. concentric force, eccentric force, isometric force, power, speed, etc…). Thus, the purpose of the systematic review was to compare the effects of the duration of static stretching performed prior to exercise on a range of physical performance measures.


OVERVIEW OF RESEARCH METHODS: A total of 106 articles were included in the systematic literature review. Each article was reviewed by 2 separate individuals and the quality of the study was evaluated using a standardized instrument (PEDro rating sheet). To determine the effects of static stretch duration on physical performance measures the authors created 4 separate categories for static stretch duration based on the protocol used in a specific study.

  • Less than 30 seconds of continuous static stretching
  • 30 to 45 seconds of continuous static stretching
  • 1 to 2 minutes of continuous static stretching
  • More than 2 minutes of continuous static stretching

Once grouping studies into the appropriate static stretch duration category the authors evaluated the stretching protocols effects on different physical performance measures used across the different studies. This was performed by determining the average change in physical performance across those studies grouped in a given stretch duration category for each of the different physical performance measures.


KEY FINDINGS: Studies using a static stretching protocol of less than 30 seconds did not negatively impact the different physical performance measures (maximal strength, speed, power).

Studies using a static stretching protocol of 30 to 45 seconds also did not negatively impact the different physical performance measures (maximal strength, speed, power).

Static stretching protocols using greater than 60-seconds of continuous stretching (1 to 2 minutes or more than 2 minutes) negatively impacted physical performance (maximal strength, speed, power). Thus, 60-seconds of continuous static stretching appears to be the threshold at which static stretching can begin to produce negative changes in physical performance measures. Interestingly, the negative change in physical performance beyond 60-seconds continues up to 2-minutes of continuous static stretching, but then plateaus at that time.


CLINICAL IMPLICATIONS: The findings of this systematic literature review may have important implications on the design of pre-exercise warm up procedures. Based on these findings a continuous static stretch held for less than 60-seconds should not have any negative impact on maximal physical performance (maximal strength, speed, or power). Given that static stretches are typically held for 30-seonds during pre-exercise warm up routines than the use of static stretches should not be harmful to physical performance performed immediately after the stretching protocol. The average change in physical performance measures for stretches held less than 60 seconds was -0.5% (SD=2.8%). Thus, these data overwhelmingly indicate that static stretching for less than 60 seconds has no detrimental effects on muscle strength, power, or speed.


As a result, static stretches should not be discouraged as part of the pre-exercise warm up routine so long as the static stretch is held for less than 60 seconds. Including static stretching may be an important component of the pre-exercise warm up routine to help establish proper muscle length prior to performing functional movements. This may in turn help minimize faulty movement patterns when performed in conjunction with other exercises to maintain muscle balance (strengthening of weak or inhibited muscles) and promote proper neuromuscular control (functional movement patterns focused on movement quality). Future research is needed to determine if incorporating static stretching with these types of exercises as part of a pre-exercise warm up routine will not only further minimize the risk of decreased physical performance, but actually improve physical performance by promoting optimal movement efficiency and control.


So if a static stretch is held too long, or applied on an individual who is unaccustomed to static stretching, their nervous system may respond by causing inhibition in the muscle they are stretching. The body is unfamiliar with this stimulus and perhaps as a protective mechanism, creates inhibition. Key points, use static stretching regularly on muscles that are shorter than they are supposed to be. This will lead to performance enhancement vs. a performance inhibitor.

Source: Eric Beard

 

Feb 14, 2013 - 08:00 AM

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