45 terms

Isometric, Isotonic, and Isokinetic Exercises

Isometric Exercise
Same length; Muscle contraction without noticeable change in length of muscle (velocity = 0); No physical work done, but tension and force output production are high; Contraction must be held for at least 6 seconds to develop peak tension
Types of Isometrics
Muscle setting, Resisted isometrics, Stabilization exercises
Muscle Setting
Low intensity against little or not resistance; Promote muscle relaxation, mobility and circulation while decreasing pain and spasm; Does not approve muscle strength but can slow muscle atrophy
Resisted Isometrics
Performed against manual or mechanical resistance; Develop strength when pain or movement limitations exist; For strength gains, use force 60-80% of muscle's max force capacity; Amount or resistance the muscle can hold will vary based on the point in the ROM at which the exercise is completed; In order to gain strength throughout the range, isometric exercises should be performed at various positions throughout the range
Stabilization Exericses
Co-contraction of msucles surrounding a proximal joint; Isometric contraction held at mid-range against gravity; Usually performed in weight bearing positions as close-chain exercises; Body weight of patient is usally the resistance provided for exercises; Rhythmic stabilization (applying resistance manually to the same joint in opposite motions to facilitate a simultaneous contraction of muscles on both sides of the joing
Be careful to avoid Valsalva maneuver (perform rhythmic breathing)
Isometric Exercise Positives
Can use initially in rehab secondary to ROM; Maintain neural connections
Isometric Exercise Negatives
Doesn't strengthen full ROM (10 degress carryover); No functional benefits
Isometric Exercise Examples
Quad sets/ham sets; Wall push-ups; Gluteus squeezes; Ball squeezes between legs
Isotonic Exercise
Same tension; Exercise carried out against a load (constant or vaiable) while the muscle shortens or elongates through the available range (velocity = variable); Used to increase dynamic strength, muscle endurance and power; May be performed with manual or mechanical resistance
Isotonic Constant vs. Variable Load
We typically think of isotonic exercise having a fixed load. However, since force production is not the same throughout the muscle with a fixed load, a variable load can be defined as isotonic. Key Point: Load cannot be greater than what the weakest point of the muscle can lift; Variable loads allow the resistance to change throughout the full ROM in order to provide load on the muscle at multiple pints throughout the ROM
Isotonic Concentric vs. Eccentric
Should usally include a omponent of each; this most resembles functional use of muscles; Concentric; Eccentric
Isotonic Concentric
Tension develops as muscle is shortened when external force is applied
Isotonice Eccentric
Tension Develops as muscle is elongated when external force is applied; Provide shock absorption during closed-chain activites; Greater force production capabilities than concentric contraction; More efficient than concentric contraction (less effort required); May be easier to perform in acute phases of rehab than concentric exercies; Control greatest load-->maximal resistance can be used in later stages of rehab; Greater resistance to fatigue by consuming less oxygen and fewer energy stores
Isotonic Precautions
Increased stress on cardiovascular system (should teach thrymic breathing); DOMS (keep load low acutely and progressively increases)
Isotonic Force Production Variations
Max eccectric contaction produces greater force than max concentric contraction; The same force production for concentric contraction requires a greater number of motor units be recruited
Isotonic Velocity alters production of force via neuromuscular unit capacity
Slow Velocity; Higher velocity; For strength training, slow speed is utilized with heavy loads
Slow Velocity
Greater force with eccentric contraction
Higher Velocity
Eccentric contraction levels off or lsightly increases while concentric contraction decreases
Isotonic Positives
Multiple points get load; Can be open or closed chain; Easy application; Can be inexpensive; Contraction against a maximal load produces more tension than an isometric contraction
Isotonic Negatives
Only can use oad the weakest point can lift; Requires training on proper completion for safety
Isotonic Concentric Examples
Lifting weights, push-ups (lowering phase), theraband
Isotonic Eccentric Examples
Lowering weights, releasing theraband, slow stand/lowering to sit
Open Kinematic Chain
Exercise is when the distal end of the moving segment moves freely
Open Kinematic Chain Exercise
Can be performed with manual or mechanical resistance, dynamically or statically; If weight bearing is contraindicated, this will be the only type of exercise; Don't prepare patient for funtional performance of skills if not used in combination with close-chain, weight-bearing exercises
Open-Chain Kinematic Positives
Allow isolation of one joint or muscle; Can get infor about torque production with isokinetics; Decreased resitance forces
Open-Chain Kinematic Negatives
Don't help joint position sense or proprioception; Increased acceleration and joint deformation; Increased mechanoreceptor deformation
Open-Chain Kinematic Examples
SAQ/LAQ; Ankle circles; Heel slides/ abduction slides
Exercise is when the body moves over a fixed distal segment
Closed-Chain Exercise
Can be performed with manual or mechanical resistance, using the patient's body weight, and in a dynamic and static fashion; Involve concentric, eccentric and isometric contractions; Provide load for muscles, joints, bones and noncontractile tissues; Stimulate mechanoreceptors within joints-->co-contraction-->increased stability; Improve muscle power/strength/endurance, stability, balance, and coordination; Can't be performed if NWB; Goor for improving stability in shoulder and hip girdles
Closed-Chain Positives
Teach agonist/antagonist relationships; Can be multiplaner; Force begins at the ground; Each joint absorbs some of the force; Decreased shearing forces; Decreased acceleration forces; Increased joint congruency; FUNCTIONAL!!!
Closed-Chain Negatives
Too much strain for patients with RA; Difficult to see muscle compensations
Closed-Chain Examples
Weight shifting, wall push-ups, lifting weights, standing activities
Isokinetic Exercise
Same movement speed; Movement occurring at a constant, controlled speed (velocity=constant); Resistance will vary throughout the RAM, as exercise load changes in relation to the ability of the muscle to produce force in various parts of the ROM; Allow concentric and eccentric exercise; Strength gains appear to be speed dependent: training speed=speed where the strength gains occur; Can safely perform movements at high rate that would cause damage in isontonic exercises
Isokinetic Concentric
Capacity of muscle to produce force decreases as speed increases
Isokinetic Eccentric
Capacity to produce force may increase to a point as speed increases
Isokinetic Positives
Maximum resistance through full ROM: can change at weaker points in ROM; High speed (500 degrees/sec); Provides good objective data (work comp)
Isokinetic Negatives
Expensive equipment; No interia; Requires training of staff
Isokinetic Examples
Cybex; Kincom; Cam and pulley system; Athletic Rehab
Isotonic Equipment
Free weights; Elastic resistance devices; Pulley systems; Trampoline; Variable-resistance equipment; Swiss ball; Body blade; Exercise bike; Resistive reciprocal exercise unit; Closed-chain resistance devices
Isomentric Equipment
Use isotonic equipment to hold weight that is too heavy for patient to life; Isokinetics set at 0 degrees/sec
Isokinetic Equipment
KIN/COM. Biodex, Lido, Merac, Cybex II, UBE, Orthotron II
Isometric Regimens
Breif repetitive; Multiple-angle
Breif Repetitive
Hold isometric contraction for 6 seconds; 20 second between contractions; Up to 20 contractions can be performed
Used to achieve increased strength throughout ROM, as physiological overflow occurs only in 20 degrees surrounding training angle; Resistance should be applied at last every 20 degrees to strengthen entire ROM; One regimen has 10 reps, 10 bouts, 10 second contraction every 10 degrees