Isokinetic exercises
- 2. DEFINITION • IT IS A FORM OF DYNAMIC EXERCISE IN WHICH THE VELOCITY OF MUSCLE SHORTENING OR LENHTHENING AND THE ANGULAR LIMB VELOCITY IS PRE-DETERMINED AND HELD CONSTANT BY A RATE- LIMITING DEVICE KNOWN AS AN ISOKINETIC DYNAMOMETER. • THE TERM “ISOKINETIC” REFERS TO MOVEMENT THAT OCCURS AT EQUAL (CONSTANT) VELOCITY. • THE FORCE ENCOUNTERED BY THE MUSCLE DEPENDS ON THE EXTENT OF FORCE APPLIED TO THE EQUIPMENT. • IT IS ALSO CALLED ACCOMODATING RESISTANCE EXERCISE.
- 3. FOR EXAMPLE: • INDIVIDUAL IS PUTTING FORTH MAXIMUM EFFORT DURING EACH REPETITION OF EXERCISE, THE CONTRACTING MUSCLE PRODUCES VARIABLE BUT MAXIMUM FORCE OUTPUT, CONSISTENT WITH THE MUSCLE’S VARIABLE TENSION- GENERATING CAPABILITIES AT ALL PORTIONS OF RANGE OF MOTION.
- 4. CHARACTERSTICS OF ISOKINETIC TRAINING 1. CONSTANT VELOCITY: FUNDAMENTAL TO THE CONCEPT OF ISOKINETIC EXERCISE IS THAT THE VELOCITY OF MUSCLE SHORTENING OR LENGTHENING IS PRESET AND CONTROLLLED BY THE UNIT AND REMAINS CONSTANT THROUHOUT THE R.O.M. 2. RANGE AND SELECTION OF TRAINING VELOCITIES: • ISOKINETIC TRAINING AFFORDS A WIDE RANGE OF EXERCISE VELOCITIES IN REHABILITATION FROM VERY SLOW TO FAST VELOCITIES. • CURRENT DYNAMOMETERS MANIPULATE THE VELOCITY OF LIMB MOVEMENT FROM 0 DEGREE /SECOND (ISOMETRIC MODE) UP TO 500 DEGREE/ SECOND.
- 5. CONSTANT VELOCITY RANGE AND SELECTION OF TRAINING VELOCITIES
- 6. • THESE TRAINING VELOCITIES ARE CLASSIFIED AS : SLOW MEDIUM FAST • THE RANGE THEORETICALLY PROVIDES A MECHANISM BY WHICH A PATIENT CAN PREPARE FOR THE DEMANDS OF FUNCTIONAL ACTIVITIES THAT OCCUR AT RANGE VELOCITIES OF LIMB MOVEMENT. • SELECTION OF TRAINING VELOCITIES SHOULD BE SPECIFIC IN FASTER TRAINING MODE OF EXERCISE VELOCITIES In motor skills such as walking or Concentric or eccentric Lifting. - concentric exercise are substantially For eg: angular velocity is calculated greater than eccentric exercise as 230* to 240* (concentric > eccentric)
- 8. • RECIPROCAL VERSUS ISOLATED MUSCLE TRAINING: USE OF RECIPROCAL TRAINING OF AGONIST AND ANTAGONIST MUSCLES EMPHASIZING QUICK REVERSALS OF MOTION POSSIBLE ON AN ISOKINETIC DYNAMOMETER. FOR EG: TRAINING PARAMETER CAN BE SET SO THE PATIENT PERFORMS CONCENTRIC CONTRACTION OF QUADRICEPS FOLLOWED BY CONCENTRIC CONTRACTION OF HAMSTRINGS. OR AN ALTERNATIVE APPROACH: TARGET THE SAME MUSCLE IN CONCENTRIC MODE, FOLLOWED BY ECCENTRIC MODE, THUS STRENGTHENING ONE MUSCLE GROUP AT A TIME. BOTH THE TECHNIQUES HAVE THEIR OWN MERITS.
- 10. 4. SPECIFICITY OF TRAINING: ISOKINETIC TRAINING VELOCITY SPECIFIC MODE-SPECIFIC • More prevalent (concentric vs eccentric) • Patient typically exercise at several velocities ( b/w 90* to 360*/sec) VELOCITY SPECTRUM REHABILITATION 5. COMPRESSIVE FORCES ON JOINTS: DURING CONCENTRIC EXERCISE, AS FORCE OUTPUT DECREASES, THE COMPRESSIVE FORCES ACROSS THE MOVING JOINT ARE LESS AT FASTER ANGULAR VELOITIES THAN AT SLOW VELOCITIES. 6. ACCOMODATION TO FATIGUE: BECAUSE RESISTANCE ENCOUNTERED ∝ FORCE APPLIED TO THE RESISTANCE ARM OF THE ISOKINETIC UNIT
- 11. • CONTRACTING MUSCLE FATIGUES, THEN ALSO PATIENT IS ABLE TO PERFORM ADDITIONAL REPETITIONS EVEN THROUGH THE FORCE OUTPUT OF THE MUSCLE TEMPORARILY DIMINISHES. 7. ACCOMODATION TO PAINFUL ARC: • IF THE PATIENT EXPERIENCES TRANSIENT PAIN AT SOME PORTION OF THE ARC OF MOTION DURING EXERCISE, ISOKINETIC TRAINING ACCOMODATES FOR THE PAINFUL ARC. • THE PATIENT SIMPLY PUSHES LESS VIGROUSLY AGAINST THE RESISTANCE ARM TO MOVE WITHOUT PAIN THROUGH THE PORTION OF THE RANGE. • IF THE PATIENT NEEDS TO STOP A RESISTED MOTION BECAUSE OF SUDDEN ONSET OF PAIN, THE RESISTANCE IS ELIMINATED AS SOON AS THE PATIENT STOPS PUSHING AGAINST THE TOEQUE ARM OF DYNAMOMETER.
- 12. STUDY OF MUSCLE FATIGUE IN ISOKINETIC TRAINING
- 13. SPECIAL CONSIDERATIONS OF ISOKINETIC TRAINING • AVAILABILITY OF EQUIPMENT: ONE LIMITATION OF ISOKINETIC EXERCISE IS THAT A PATIENT CAN INCOPORATE THIS FORM OF EXERCISE INTO A REHABILITATION PROGRAM ONLY BY GOING TO A FACILITY WHERE THE EQUIPMENT IS AVAILABLE. IN ADDITION, PATIENT MUST BE GIVEN ASSISTANCE TO SET UP THE EQUIPMENT AND OFTEN REQUIRES SUPERVISION DURING EXERCISE. APPROPRIATE SETUP: THE SETUP RECOMMENDED IN THE PRODUCT MANUALLY OFTEN MUST BE ALTERED TO ENSURE THAT THE EXERCISE OCCURS IN A POSITION THAT IS SAFE FOR A PARTICULAR JOINT. FOR EXAMPLE: EVEN THOUGH A MANUFACTURER DESCRIBE A 90*/90* POSITION OF SHOULDER AND ELBOW FOR STRENGHTENING OF SHOULDER ROTATORS, EXERCISING WITH THE ARM AT THE SIDE MAY BE SAFER, MORE COMFORTABLE POSITION.
- 14. For example: 90*-90* position for strengthening of shoulder rotators More comfortable position preferred that is arm at side
- 15. INITIATION AND PROGRESSION OF ISOKINETIC TRAINING DURING REHABILITATION ISOKINETIC TRAINING TYPICALLY IS BEGUN IN THE LATER STAGES OF REHABILITATION: WHEN ACTIVE MOTION THROUGH THE FULL (OR PARTIAL) ROM IS PAIN- FREE. INITIALLY, TO KEEP RESISTANCE LOW, SUBMAXIMAL ISOKINETIC EXERCISE IS IMPLEMENTED BEFORE MAXIMAL EFFORT ISOKINETIC EXERCISE. SHORT ARC MOVEMENTS ARE USED BEFORE FULL ARC MOTIONS, WHEN NECESSARY TO AVOID MOVEMENT IN AN UNSTABLE OR PAINFUL PORTION OF THE RANGE. SLOW TO MEDIUM TRAINING VELOCITIES (60*- 80*/ SEC) ARE INCORPORATED INTO THE EXERCISE PROGRAM BEFORE PROGRESSING TO FASTER VELOCITIES.
- 16. Short arc 0* to 60* no pain performed initially Full arc 0* to 120* leads to pain performed later on after progression Resistance in dynamometers
- 17. • MAXIMAL CONCENTRIC CONTRACTIONS AT VARIOUS VELOCITIES ARE PERFORMED BEFORE INTRODUCING ECCENTRIC ISOKINETIC EXERCISES FOR THE FOLLOWING FOR THE FOLLOWING REASONS: CONCENTRIC ISOKINETIC EXERCISES ARE EASY TO LEARN AND IS FULLY UNDER THE CONTROL OF THE PATIENT. DURING ECCENTRIC ISOKINETIC EXERCISE, THE VELOCITY OF THE MOVEMENT OF THE RESISTANCE ARM IS ROBOTICALLY CONTROLLED BY THE DYNAMOMETER, NOT THE PATIENT.
- 18. ISOKINETIC DYNAMOMETERS • RATE LIMITING DEVICES THAT CONTROL THE VELOCITY OF MOTION, PROVIDE ACCOMODATING RESISTANCE DURING DYNAMIC EXERCISES, OF THE EXTRIMITIES OR TRUNK. • THE EQUIPMENT SUPPLIES RESISTANCE PROPORTIONAL TO THE FORCE GENERATED BY THE PERSON USING THE MACHINE. • FEATURES: COMPUTERISED TESTING CAPABILITIES PASSIVE AND ACTIVE MODE THAT PERMIT OPEN-CHAIN, CONCENTRIC AND ECCENTRIC TESTING AND TRAINING. VELOCITY SETTINGS FROM 0*/SEC FOR ISOMETRIC EXERCISE; CONCENTRIC EXERCISES : 500*/SEC ECCENTRIC EXERCISES : UP TO 120* TO 250*/SEC
- 20. • SINGLE JOINT,UNIPLANAR, OPEN CHAIN MOVEMENTS ARE MOST COMMON BUT ADAPATATIONS ARE AVAILABLE THAT PERMIT MULTIPLANAR MOVEMENT PATTERNS AND MULTIJOINT, CLOSED CHAON EXERCISES. • RECIPROCAL TRAINING OF AGONIST/ ANTAGONIST, CONCENTRIC/ECCENTRIC EXERCISE OF SAME MUSCLE GROUP ARE POSSIBLE. ADVANTAGES: THE MAIN ADVANTAGE ASSOCIATED WITH ISOKINETIC EXERCISES IS ITS ABILITY TO WORK MAXIMALLY i.e. THE ABILITY TO WORK AT VARIOUS VELOCITIES IN ORDRER TO MIMIC THE FUNCTIONAL ACTIVITIES. FOR EXAMPLE : VELOCITY MEASURED TO HIP AND KNEE DURING SOCCER KICK MAY EXCEED 400*/ SEC AND 1200*/ SEC RESPECTIVELY. IT PROVIDES MAXIMUM RESISTANCE AT ALL POINTS OF ROM. ACCOMODATES FOR PAINFUL ARC
- 21. DISADVANTAGES OF DYNAMOMETERS LARGE AND EXPENSIVE MOST UNITS ALLOW ONLY OPEN CHAIN (NON- WEIGHT BEARING) MOVEMENT PATTERS, WHICH DO NOT STIMULATE LOWER EXTRIMITY MOVEMENT PATTERNS AND SOME UPPER EXTRIMITY FUNCTIONS.
- 22. Technical Features • There are two major types of machine available to offer isokinetic exercise; • 1. Type 1 - An active dynamometer – in this type of exercise, the speed is controlled whilst resistance is variable according to the amount of force throughout the range of movement. • 2. Type 2 – utilizes a change in the moment arm of the selected resistance to coincide with the change in moment arm of the muscle effort and the change in tension due to muscle length change. • Isokinetic exercise machines or isokinetic dynamometers are mainly used to measure muscular strength in musculoskeletal rehabilitation which aims to restores optimal form of function after injury or surgery. The final stage of rehabilitation aims to return an individual to normal activities via resistance exercises that are usually focused at regaining muscle strength. • Most isokinetic exercise machines are equipped with these components: • Computer System/Clinical Data System • Dynamometer • Attachments to parts of body, such as attachment for ankle, knee, shoulder, elbow, wrist, hip and/or upper body extremity table.
- 24. infrastructure • Isokinetic exercise machines are bulky. • The total operating floor spaces required differ from one model to another. • For example Cybex 6000 needs about 120 square feet area to be installed whereas newer models such as Biodex System 4 Pro System 4 Quick Set require 32 square feet. • The space requirement aspect therefore needs to be considered when one is planning to procure the isokinetic exercise machine.
- 25. FLOOR LAY OUT FOR CYBEX 6000
- 26. VARIOUS ISOKINETIC DYNAMOMETERS BIODEX : • The Biodex is a multi-mode computerized robotic measuring instrument designed to measure muscle strength. It measures muscle strength by applying constant resistance against muscles in repetitive motions quickly and as powerfully as possible. • If test results show muscle weakness (compared with your same age and sex comparison group) strengthening exercises may be prescribed. The test may be repeated periodically to monitor how strength is improving as a result of a strength training intervention program. • We use the Biodex: • to assess strength of muscles around joints • as part of a rehabilitation exercise to improve the strength of various joints • There are 5 modes that can be used: Isokinetic Resistance, Reactive Eccentric, Passive Motion, Isometric, Isotonic • Speed: 450 eccentric
- 27. Cybex • A CYBEX ISOKINETIC TEST IS USED TO MEASURE THE MAXIMUM STRENGTH OF A JOINT THROUGHOUT ITS AVAILABLE RANGE-OF-MOTION (ROM). THE TEST COMPARES THE INVOLVED SIDE TO THE UNINVOLVED SIDE. RESULTS ARE USED TO DESIGN REHABILITATION PROTOCOLS AND HELP MAKE RETURN TO SPORT AND RETURN TO WORK DECISIONS. • MODES: ISOKINETIC ECCENTRIC CONCENTRIC CPM • SPEED: 500 CONCENTRIC
- 28. KIN-COM DYNAMOMETER • The Kin-Com@ is a computer controlled electromechanical dynamometer. • The device provides resistance during isokinetic (constant velocity) movement and during isometric muscle contractions. • MODES: ISOMETRIC ISOKINETIC ISOTONIC CPM
- 29. PARAMETERS • FORCE: A force is a push or pull upon an object resulting from the object's interaction with another object. Whenever there is an interaction between two objects, there is a force upon each of the objects. When the interaction ceases, the two objects no longer experience the force. Its unit is newton • TORQUE: Torque is a measure of the force that can cause an object to rotate about an axis. Just as force is what causes an object to accelerate in linear kinematics, torque is what causes an object to acquire angular acceleration. Torque is a vector quantity. Its unit is newton meters.
- 30. PEAK FORCE: It is the point of highest torque production AVERAGE FORCE: The average force is the force exerted by a body moving at a defined rate of speed (velocity) for a defined period of time. Thus, average Force is equal to the mass of the body multiplied by the average velocity over the defined time. • It is a force or a torque produced along the whole ROM. WORK: n physics, work is the product of force and displacement. A force is said to do work if, when acting, there is a displacement of the point of application in the direction of the force. • It is represented by area under the torque or force curve. • SI base units: 1 kg⋅m2⋅s−2 • SI unit: joule (J) • Other units: Foot-pound, Erg POWER: Rate of performing work • Power characteristics are evaluated by identifying by the amount of work performed in specific period.
- 31. ISOKINETIC TRAINING PROGRAM • FORCE-VELOCITY CURVE IS A USEFUL TOOL. • THE FORCE PRODUCTION IS LOCATED ON Y-AXIS AND VELOCITY ON X- AXIS. • CONCENTRIC MOTION IS ON RIGHT SIDE OF X-AXIS AND ECCENTRIC MOTION ON LEFT SIDE OF X-AXIS. Y-AXIS X-AXIS FORCE ECCENTRIC CONCENTRIC VELOCITY
- 32. Progression • Progression through rehabilitation program should be based on short term goal and phase of healing post injury. • In ACUTE PHASE the main aim is to regain weight and strength. Thus, the isokinetic dynamometer can be used in this phase to provide isometric and submaximal isotonic resistance. • In PROLIFERATIVE STAGE, passive motion is required as the healing progresses. • FOR STRENGTHENING: Graded resistive stresses can be given. • THUS ISOKINETIC DYNAMOMETER CAB BE USED FROM SUBMAXIMAL TO MAXIMAL ISOTONIC. • In REMODELLING STAGE: More aggressive strengthening is required.
- 33. • INITIALLY, TO KEEP THE RSISTANCE LOW, SUB-MAXIMAL ISOKINETIC EXERCISES ARE IMPLEMENTED BEFORE ISOKINETIC EXERCISES WITH MAXIMAL EFFORT. • SHORT ARC MOTION IS USED BEFORE FULL ARC MOTION TO AVOID PAINFUL ROM. • THIS IS ACCOMPLISHED BY MECHANICAL DEVICE DYNAMOMETER. • SLOW TO MEDIUM TRAINING VELOCITIES 60-180* ARE USED BEFORE PROGRESSING TO FASTER VELOCITIES. • ECCENTRIC IS PREFERRED INITIALLY THAN CONCENTRIC EXERCISES.