Passive Stretches
Passive stretches are achieved as the name implies, through the use of mechanical devices, the assistance of gravity, or use of a partner. Muscles around the joint undergoing a passive stretch remain inactive.
Contents
Mechanical Devices
Joint Active Systems are splints applied across a joint to gain range of motion passively. Stretching exercises can be done passively using this device to apply a low amplitude force across a joint over a long period of time. Passive stretches done in this way can create "creep" in viscoelastic tissues - a long term lengthening of the soft tissues around a joint. The amount of creep is dependent upon the time the stretch is applied, heat of the tissues, and the force applied.
A Partner
Passive stretches are done in athletics amongst team members. One individual will apply a stretch to another's limbs in an attempt to gain greater range of motion in an area that is difficult for a player to stretch himself. One obvious drawback of this type of stretching is the risk of injury with an inappropriate use of force.
A Physical Therapist
Stretching exercises can be done passively in the rehabilitative setting when an individual is too weak to perform the stretch himself. The physical therapist may also be able to apply a stretch to a particular muscle or fascia more effectively than a patient can himself. It is important that this specific type of stretching be done under the direction of a medical professional.
Gravity Assisted
Gravity assisted stretching exercises are done by using the force of gravity against a limb. An example of this is the back extension stretch done lying back over the exercise ball.
Active vs Passive Stretches
Research published in the journal Physical Therapy in 2004 looked at 33 people with hip flexor tightness with an average age of 23.6 years. After 6 weeks of a home stretching program, both the active stretching and the passive stretching groups had significantly improved their hip range of motion. One was not found to be significantly better than the other. (1)
Effects on Performance
In those sports whose success is dependent on torque and power, several
studies have shown that passive stretching exercises done prior to that
sport are detrimental to one's ability to generate forceful isometric
and concentric contractions. (2,3,4)
This may be due to one or more of the following reasons:
- In an unstretched muscle the contractile elements are at a more favourable point on the force-velocity curve.
- The unstretched muscle may be at an optimum point on the force-length curve.
- There is less "slack" in an unstretched muscle to take up during the beginning of the contraction.
- There may be a dampening of the stretch reflex thereby impacting the stretch-shortening cycle required in sports requiring ballistic movements.
- Less elastic energy is stored in the noncontractile elements of the muscle.
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1.
MV Winters,
CG Blake,
JS Trost,
TB Marcello-Brinker,
L Lowe,
MB Garber,
RS Wainner Passive Versus Active Stretching of Hip Flexor
Muscles in Subjects With Limited Hip Extension: A Randomized Clinical
Trial. Physical Therapy September 2004 vol. 84 no. 9 800-807
2. Avela, J., Kyrolainen, H., & Komi, P. V. (1999). Altered reflex
sensitivity after repeated and prolonged passive muscle stretching.
Journal of Applied Physiology, 86, 1283 – 1291.
3. Cornwell, A., Nelson, A. G., Heise, G. D., & Sidaway, B. (2001).
The acute effects of passive muscle stretching on vertical jump
performance. Journal of Human Movement Studies, 40, 307 – 324.
4. Young, W. B., & Behm, D. G. (2003). Effects of running, static
stretching and practice jumps on explosive force production
and jumping performance. Journal of Sports Medicine and Physical Fitness, 43, 21 – 27.