Isometrics

What is isometrics

same measurement- no appreciable change in muscle length; joint stays still a static form of exercise in which muscle contracts and produces force without an appreciable change in the length of the muscle and without visible joint motion

Examples of isometric exercises

Sources of resistance include holding against a force applied manually, holding a weight in a particular position, maintaining position against the resistance of body weight, or pushing or pulling an immovable object

Effects of isometrics

There is not significant carryover to isotonic strength. Multi-angle isometrics may help with this, but is not a good substitute for isotonic exercise if you want isotonic strength (movement strength). Therefore, it is valuable mostly to static activities Must hold for 6 secs at 75% maximum voluntary contraction to increase strength (not done during the acute, inflammatory stage) Mostly recruits slow twitch muscles Vasoconstriction and joint compression occur-For example, there are significant compressive forces at the hip when performing a glut set. May contribute to Valsalva, putting extra load on cardiovascular system. Exhale on effort

Stabilization isometric exercises

This form is used to develop a sub-maximal but sustained level of co-contraction to improve postural stability or dynamic stability of a joint by means of midrange isometric contractions against resistance in anti-gravity positions and in WB postures if WB is permissible. Body weight or manual resistance is typically the source of resistance associated with PNF

Name contraindications for isometrics

Valsalva Unstable cardiovascular patients or significant HTN Hernias Muscle and tendon tears Fractures (muscle setting may be allowed but not resisted isometrics) Pain (increased due to isometrics) Any time resisted exercise should be avoided (resisted isometrics)

What should you do during isometrics to prevent valsalva?

exhale on effort

Contrainindications in book for isometrics

history of cardiac and vascular disorders

Types of Isometrics

muscle setting resisted isometrics

What is resisted isometrics

pushing against an immovable object (like a door)

What is muscle setting

tensing the muscle (example: patient supine on table; tell them to act like they're pushing knee down into table) Used to decrease muscle pain and spasm and to promote relaxation and circulation after injury to soft tissues during the ACUTE stage of healing (p. 179 and ppt) Does not improve muscle strength, except in very weak muscles. However, setting exercises can retard muscle atrophy and maintain mobility between muscle fibers when immobilization of a muscle is necessary to protect healing tissues during the very early phase of rehabilitation

Rationale for use of isometric exercise

the need for static strength and endurance is apparent in almost all aspects of control of the body during functional activities. Loss of static muscle strength occurs rapidly with immobilization and disuse from 8% per week to as much as 5% per day (p. 179)

Indications for isometrics

1. prevent atrophy and help maintain strength when joints are acutely inflamed 2. can be done in an immobilization device to reduce atrophy 3. to promote stabilization of a joint

How many seconds should you hold isometric exercises

6 seconds

True or False: Vasodilation occurs during isometric exercises

False-vasoconstriction and joint compression occur

Is mechanical work done in isometrics

No-but a measurable amount of tension and force output are produced by the muscle