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Bad Stretching


How do you decide what is a good stretch and what is just bad stretching? Most of my patients are well informed. They investigate disorders on line, they discuss problems in the gym, and they talk to me freely about their concerns. One concern that has been brought up time and time again is what is considered a bad stretch and what is a good stretch.  When should you stretch, and when should you not stretch?

Why is static stretching getting a bad rap and is there such a thing as a bad method of stretching? Not all stretching is good and not all stretching is appropriate for all occasions. Bad stretching is really a matter of bad timing.

When is Stretching Bad?
Should Stretching be Included in a Warm up?
The Effects of Static Stretching on Muscle Force
Summary & Recommendations to avoid bad stretching.
Contraindications to Stretching

bad stretching

When is it a Bad Stretch?

We want to avoid any activity that will hinder our performance. If that performance involves feats of strength or power, then static stretching  should be left for after the activity. If that activity requires extreme flexibility rather than strength then avoiding static stretching is not as important. Literature suggests that static stretching can reduce the force generated by a muscle by up to 30% for up to 30 minutes.

Stretching is also bad when it reinforces poor posture and movement patterns. For instance, those of us that bend forward repeatedly at work benefit little from stretches that flex our lumbar spine. Repeated flexion of the lumbar spine can cause disk injuries, so we don't want to reinforce this movement in our exercises.

Stretching joints that are already unstable can cause further injury. If you've dislocated a joint, have a hypermobility disorder, or if your are involved in a sport that predisposes you to laxity, you should consult a physical therapist to advise you on a stretching regimen.

Click here for a list of contraindications to stretching, and if you have any concerns ask your physical therapist for advice.

Should Stretching be Included in a Warm up?

The way one stretches prior to an activity is very different than how one should stretch after a sport or activity. A proper warm up is believed by most educated people in the field to be necessary to optimize performance in a sport in order to warm up muscles and joints. Whether or not to stretch during this warm up has been a bone of contention for many athletes and the subject of plenty of research. Studies and anecdotal evidence exists supporting both view points. Perhaps it is not a question of whether or not to stretch but simply when and how is appropriate for a given sport. Bad stretching is really a matter of bad timing.

Stretching as part of a pre game warm up  will
  • Increase blood flow to the muscles
  • Increase alertness
  • Prepare the sympathetic nervous system
  • Increase soft tissue compliance
This is achieved through dynamic stretching.                          

After activity is the time for recovery when you can restore your flexibility.  When the muscles are warm is the optimum time to gain flexibility and after activity will help to minimize post exercise soreness.
  • Relieve knots
  • Minimize post exercise muscle soreness
  • Lengthen soft tissues.
This is achieved through static stretching.
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The Effects of Static Stretching on Muscle Force

There are three mechanisms that are implicated in the reduction of force and power produced by a muscle after static stretching:
  • Changes in mechanical properties of the musculotendinous complex - the muscle may operate with a different length-tension relation. Lengthening the musculotendinous unit will alter the maximum force able to be generated by a muscle according to its force-length relationship. That is every muscle has an optimum length at which it can create maximum force. If that muscle is lengthened, or shortened, the maximum force that muscle can generate at that new length is reduced.
  • A decrease in neuromuscular activation due to inhibition.
  • There have been reductions noted in neuromuscular activity (EMG activity)  30 minutes and an hour after static stretching. (1,2); although, I haven't come across any literature that explicitly examines the relationship between emg activity and force development in a muscle.
Another hypothesis is that a stretch causes microscopic damage to the muscle fibres. The basic literature suggests strains of 20% beyond the resting length of a muscle fibre can create muscle damage that results in a decrease in force.

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In Summary

  • Regular stretching, daily or even three times per week, separate from a strenuous workout may improve flexibility and therefore performance in some sports that require flexibility.
  • Some research suggests that warm ups that don't include static stretching may improve performance and reduce injuries in some sports.
  • Stretching just prior to an exercise that requires a great force production may hinder performance.
  • Static stretching done during warm ups can increase flexibility for a short period of time, but there are no studies that confirm that exercise performance is improved because of it.
  • In order to lengthen a muscle the time a stretch must be held will vary depending on age, fitness level, prior injuries, and other systemic conditions ( i.e. connective tissue disorders, autoimmune disorders, etc.)

Recommendations

  1. If you are going to stretch be sure to warm the muscles up first through an aerobic activity such as cycling, swimming, jogging, etc. The type of warm up activity should correlate to the muscle being stretched. For instance, if you are concerned with stretching quadriceps, then a treadmill on an incline or stepper works well to warm those muscles up. If you are concerned with hamstrings, then the cycle is more efficient as warming up the hamstrings.

  2. If you are going to be involved in weight lifting or another activity that requires feats of strength, do not stretch first. Wait until after your activity.
  3. In this case static stretching can be considered "bad stretching".
  4. Prior to returning to any kind of exercise or athletic program after an injury, consult with a physical therapist to determine your limitations and what is appropriate for you.
Remember, bad stretching is really just bad timing.

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1. Avela J, Kyröläinen H, Komi PV. Altered reflex sensitivity due to repeated and prolonged passive muscle stretching. J Appl Physiol 86: 1283-1291, 1999.
2. Avela J, Finni T, Liikavainio T, Niemela E, Komi PV. Neural and mechanical responses of the triceps surae muscle group after 1 h of repeated fast passive stretches. J Appl Physiol 96: 2325-2332, 2004.