Karate Stretching

by Nina Cheong

What is stretching?

A maneuver used to lengthen shortened soft tissue structures.

Some kinds of stretching:

  • Static: Subject not moving
  • • Passive static: no voluntary or reflex muscular resistance
  • • Active static: force produced by an opposing muscle action (ie using quad ext to stretch ham)
  • Dynamic: How much resistance to active mvt. – Limb repeatedly taken through ROM actively individual.
  • • Good for high velocity exercises (static sometimes is not beneficial for high velocity).
  • • Ie: stretch kicks
  • Ballistic: Rapid lengthening of the muscle by use of jerking or bouncing movements. Usually not recommended
  • • Don't want to set off the primary nerve endings (will cause contraction)
  • • Too forceful: may cause microtrauma
  • • May cause more elastic than plastic changes

Resistance to Stretch:

Neurophysical constraints: want to minimize the active contraction of muscle being stretched
Biomechanical stiffness:
•Stiffness of tissue
•Compliance of tissue: compliant tissue will have good change in length w/ little force required
•Stretch tolerance: Feel less pain for the same force applied to the muscle
•Flexibility: an intrinsic property of body tissues that determines the range of motion that can be achieved without injury at a jt or group of jts.
--Flexibility = stiffness + stretch tolerance -> You go farther because you don’t feel the pain as much (stiffness usually doesn’t change)
•Dependent on the viscoelasticity of muscles, ligaments, and CT.

Viscoelastic properties:

•Elastic: Permits recovery from deformation or elastic deformation (like a rubber band)
•Viscoelastic deformation: increased muscle length can occur with sufficient duration and magnitude of stretch, but the muscle’s elastic property limits magnitude and duration of the increased length (must stretch for a long time to get permanent changes: plastic deformation)

What is the goal?

  1. Increase ROM/flexibility
  2. Improve performance
  3. Decrease soreness
  4. Decrease risk of injury

What does the literature say about stretching?

… Need more research in this field still

  • •Stretching to increase joint flexibility: Not due to decrease in muscle stiffness
  • ••Due to indirect decrease of reflex inhibition, therefore changes in viscoelasticity from decreased actin-myosin crossbridges
  • ••Most likely due to stretch tolerance
  • •Duration of increased flexibility after stretching is from 6-90 minutes (hard to maintain because of elasticity)
  • •Extensive stretching program for several weeks duration has produced increased flexibility lasting for several weeks (ie why ballerinas have to stretch all the time)
  • •Adverse effects of stretching:
  • ••Stretching before exercise is more likely to cause injury than to prevent it
  • •••Increased compliance decreases amount of energy that can be absorbed
  • •••Muscles can be injured during eccentric activity even though they are not stretched beyond end range
  • •••Mild stretching can cause damage at the cytoskeleton level
  • •••Stretching masks muscle pain (increase stretch tolerance ? overstretch)
  • •••Decreased joint stability making joint motion less efficient
  • •••Body positions with dangerous loading effects that can stretch ligaments too far.
  • •Decreased soreness (DOMS): Evidence doesn’t support stretching to reduce DOMS
  • •Improved performance: Advantageous for stretch-shortening cycle activity but disadvantage for isometric and concentric performance
  • ••Shown to decrease leg strength, jump height, and peak jump force

Stretching Guidelines:

  • ••5-10 minutes aerobic warm-up: You should never stretch a cold muscle
  • •Stretch to the point of discomfort, not pain. Relax during stretch and you can go farther.
  • •Must stretch both the agonist and antagonist muscle to avoid muscle imbalances.
  • •Flexibility is specific to each joint, so you need to include all jts that will be involved the exercise/activity.
  • •Dosage: 15-60 seconds static (research suggests 30s), 2-3x/week (ACSM rec.)
  • •Force and duration:
  • ••Plastic deformation: Low force, long duration *
  • ••Elastic deformation: High force, low duration
  • •Must strengthen muscle in the new range!
  • •Direction of the stretch is applied parallel to the direction of the muscle fibers (in UE/LE usually parallel to the bone, palpate)

Key principles and considerations:

  • •Posture: Start and end postures based on the proper posture of the associated jts based on physiologic and kinesiologic factors (osteo/arthrokinematics of the jt)
  • ••Osteo and arthrokinematics: limited motion at the jt will lead to substitutions and faulty mvt patterns
  • ••Stabilize the origin of the muscle to the insertion. (Usually proximal stabilized on distal)
  • •Put the muscle opposite of its function to lengthen (ie. All quads cause ext at the knee and hip flexion [rectus only]; so to stretch all you would flex the knee and go into hip ext)