Functional Isokinetic Resistance Training

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• Isotonic aka Dynamic External Constant Resistance (DECR)

• Isometric• Variable Resistance• Isokinetics

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Forms of Resistance Training

Isotonic/DECR• Weight remains same through full range of motion – all manner of

free weights and many weight and cable machines.– Concentric Phase – muscle shortening under tension– Eccentric Phase – muscle lengthening under tension

• User/Exerciser must control speed of movement and in fact the use of momentum can greatly increase loads and has the potential to cause injury if proper stabilization and control is not present.

• While skillful and controlled use of inertial movements such as Olympic Lifts can be VERY beneficial -- when not done properly they almost always cause injury!!!

• Acute Variables for isotonic training include amount of resistance used, reps to failure, number of sets of exercise, work/rest ratio, number of exercises, number of training sessions per week.

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Isometrics• Mostly used for stabilization exercise. • No movement so tends to be safe but lack of

force production feedback makes progression difficult.

• Acute training variables for isometric training include amount of force production (difficult to assess); time under tension, number of reps, number of sets and frequency of training.

• Does not build strength throughout range of motion

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Variable Resistance• Using a cam, altering length of lever arm/s, or using

bands or chains to change the leverage or load directly to effectively change the resistance experienced at different places in the range of motion.

• The user must control the velocity of movement because changes in speed greatly effect inertial forces and momentum and failure to do so can and does cause injury.

• Acute Variables for Variable Resistance Training are similar to DECR and the focus for progression tends to be on amount of resistance used in each exercise.

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Motorized Isokinetic Resistance• Velocity is controlled and set by motor speed. The

slower the motor speed the slower the movement speed that is possible in any exercise – the exerciser CANNOT exceed the speed set! So until the user matches and attempts to move faster than the movement speed set there is NO RESISTANCE!

• Once the user matches the movement speed the more force they apply the more resistance they get back so the resistance automatically matches the users strength at each and every point in the range of motion.

• In the same way very safe because if the user experiences discomfort at any point in range of motion and eases up resistance eases up immediately!

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DMX Isokinetic Resistance DM

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DMX Isokinetic Resistance• Speed/Intensity is controlled via the intensity dial and

in the preset programs there are preset defaults but the trainer/user can override them at any time.

• There is no eccentric phase in DMX training which means less muscle soreness and quicker recovery. – This is VERY significant for athletes because concentric only

exercise sessions can be added to existing programs to allow increased training volume without overtraining and to allow for in-season strength maintenance without overtraining.

– The lack of eccentric loading is also highly beneficial for beginning exercisers and more fragile individuals because they can safely gain strength without injuring muscles or tendons or experiencing significant muscle soreness.

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Double Concentric Exercise• DMX allows users to perform double concentric

exercises such as bicep curl/tricep pushdown or overhead press/lat pulldown which allows significantly more work per exercise and per unit of time along with significantly higher caloric expenditure!!!

• This occurs because the eccentric phase of typical resistance training is MUCH lower intensity than the concentric phase since muscles are inherently much stronger eccentrically.

• As a result the time spent doing the eccentric phase of an exercise has a very low metabolic requirement.

• Double concentric exercises also allow the user to exercise two muscles at the same time.

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DMX Isokinetic Resistance• Traditionally Isokinetics have used single joint rotational

movements such as leg extension/leg curl. DMX is a cable based system allowing compound functional movements so allows more functional movements with infinite variations.

• Resistance can be applied in any plane of motion or direction and the exerciser can quickly and easily change planes and levels allowing a dynamic workout with more work being done in less time while acquiring strength and endurance in all planes and directions of movement.

• The trainer/exerciser has control of the speed (intensity) setting and can train at different speeds safely and eliminate many momentum based injuries.

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DMX Isokinetic Resistance• Dynamic Android Touch Screen Interface–Precisely tracks force production

constantly so that you have precise calculation for work done and caloric expenditure. Allows you to see and compare force production on left and right sides in real time throughout the range of motion and stores all this data for review afterwards so you can compare one workout to another and try to beat your own records!

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Intuitive Touch Screen Interface DM

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History of Isokinetics• Isokinetics have been used for testing and

performance enhancement for over 30 years with extensive peer reviewed research published.

• As a testing tool Isokinetic Machines are referred to as “Dynamometers”. Since 1988, 30 – 40 publications per year have reported findings on data from Isokinetic Dynamometers.

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Use of Isokinetics• Documented Uses for Isokinetics include:

– Collecting and creating normative values for muscle strength– Classifying muscle performance as normal or abnormal by comparison

with the performance of contralateral muscles or normative data – Collecting torque (force) curves that might indicate whether pathology is

present– Establish the relative efficacy of various treatment and training regimens– Quantify exercise so that exercise regimens may be administered– Evaluate the effects of training or testing modes such as eccentric,

concentric or isometric, testing or training speed, and duration of training– Investigate the factors that correlate with measurements, including

muscle cross sectional area, associated electomyographic activity, type of location of electrical stimulation that causes force production, physiological factors associated with muscle performance.

– To investigate the relationship between measurements– To assess or treat persons with disabilities to determine the need for

intervention, the extent of impairment, and changes in subject performance (1)

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Key Findings from Isokinetic Research• Concentric only isokinetic exercise has been shown to increase

eccentric strength and result in significant muscle hypertrophy (2) and (23)

• Isokinetics allows you to generate progressively higher forces at higher speeds -- which is not possible with resistance methods that have an accelerating mass (such as all other free weight an weight stack machines). Since producing higher forces at higher movements speeds is critical to athletic performance this capability can be highly useful.

• With most resistance training users can accelerate resulting in momentum (not muscle force) moving the resistance through much of the range of motion and resulting in sudden significant spikes in experienced load. This can and does lead to muscular-skeletal injuries. Motorized Isokinetic equipment does not allow the user to create momentum after the user meets the particular movement speed used so the muscle/s are forced to produce force throughout the range of motion without the assistance of momentum (1).

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Key Findings from Isokinetic Research

• Research has proven that significant strength increases occur with many different combinations of movement speeds, repetitions per set, and number of sets.

• Research also shows that strength gains occur when performing as many repetitions as possible in set periods of time such as one set of as many repetitions as possible in 30 seconds

• Concentric Isokinetic Training has also been shown to increase strength when tested by other strength training methods such as isometric and variable resistance testing. The research clearly shows that concentric isokinetic training significantly increases in strength no matter what testing method is used to measure strength improvement! (3) (4)

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Optimal Sets and Repetitions

• There have been studies done investigating the optimal number of sets and repetitions of isokinetic exercise with no firm conclusions on an ideal number of sets and repetitions.

• Although there were different conclusions based on different research there was consistent agreement that the number of repetitions appears to have little impact on increases in peak torque. (5) (6) (7)

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Key Findings from Isokinetic Research• As with most resistance training methods, research on isokinetics

has shown that in general longer rest periods tend to allow more optimal development of strength and power, while shorter rest periods allow for more optimal development of muscular endurance and hypertrophy (8)

• No one single optimal training speed for isokinetic training (that would produce improved strength at all speeds) has been identified.

• Some research shows little to favor a particular speed when considering gains in peak force production. For example several studies have shown that training at 60 or 180 degrees per second results in equal gains in peak torque at 60, 120, 180 and 240 degrees per second (9, 10, 11, 12) Training at 60 or 240 degrees per second resulted in equal gains in isometric strength in one study (13)

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Isokinetic Research on Power Development• Strength = maximum force a muscle/muscle group can generate.

Power is defined as force X distance divided by time. The rate of force development is important to many everyday activities and athletic events. Rapid Force Development is a key goal in many strength training programs.

• Often trainers use lighter weights moved as fast as possible to train for power, but this greatly increases momentum and accompanying risk of injury. The same exercise done using isokinetic resistance eliminates almost all the momentum and need to decelerate at the end of the movement allowing exercisers to safely work on producing more force at higher speeds.

• Keneshisa and Miyashita (18) studied different groups training at different speeds and resultant changes in power at different speeds. Although the study used different repetition schemes for different groups, which limits general conclusions, it appears that a medium speed (179 degrees per second) is best for gains in power across all speeds.

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Isokinetic Research on Power Development

• Isokinetic training at a fast movement speed results in increased strength at a fast speed of movement to a greater extent than training at a slow speed of movement (19).

• However since higher loads can be produced at lower movement speeds with greater time under tension optimal training plans should include training sessions done at high and low speeds.

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Isokinetic Velocity Spectrum Training• To create maximum power with high loads, you need to be very

strong, while to create maximum power with light loads, you need a very high rate of force development.

• The use of Isokinetic Velocity Spectrum Training can help to address these two diverging goals and promote optimal neuromuscular response (1). This type of training involves training at several different speeds to optimize adaptation along a velocity spectrum.

• One variation of velocity spectrum exercise is in the logical order of velocity progression from low to high speeds.

• However several studies have shown that significantly greater power was produced when the faster speeds were done before progressing to the slower speeds (28, 29, 30)

• Slower speed training will tend to fatigue a muscle more rapidly than higher speed training so to optimize power development training at high velocities should proceed slower velocity strength emphasis if done within the same exercise session.

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Isokinetic Training and Athletic

Performance• Several studies have conclusively shown isokinetic training improves athletic performance and established tests related to athletic performance such as increase in vertical jump (20); increase in tennis serve speed (21) and improvement in vertical jump, 40-yard dash and softball throw (38). It is also relevant to note that several of these studies used well trained athletes for whom improvement in strength is more difficult to produce.

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Isokinetic Training versus DECR Training

• Most studies comparing the two have shown great specificity in improvement based on the modality used for training (24).

• However, Isokinetics have been shown to increase isometric strength considerably more than DECR (Dynamic External Constant Resistance) Training (24).

• Studies comparing DECR and Isokinetic Training show no clear superiority of one over the other (24, 25)

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DMX Strength Training Guidelines• Acclimatization and initial progressions

– Important to teach users that they must put significant force into the system to get resistance back because there is no inherent resistance and the user creates resistance when matching and attempting to exceed the speed setting!

– Also emphasize NOT jerking into an exercise (particularly at higher speed settings to avoid creating unnecessary momentum and to focus on joint stabilization PRIOR to the beginning of an exercise).

– Moderate movement speeds/intensity settings (8 – 12) are a good place to start when teaching beginners because they will feel load quickly but still be able to move smoothly. The use of higher speeds (intensity settings below 6) demands more control while slower speeds (intensity settings above 12) are so slow new clients may have difficulty moving throughout a repetition smoothly.

– Optimal Intensity settings ARE specific to specific movements and ultimately as the client progresses using multiple intensity/speed settings will provide the best overall results.

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DMX Acute Training Variables• Numbers of sets, repetitions per set, number of

exercises – In general with new users initially focus on volume

progressions by increasing repetitions per set, and/or number of sets and/or number of exercises to increase training volume.

• Weekly training frequency – Consider overall weekly training load, fitness level, and goals– For most users 2 – 3 sessions per week are a good starting

point.

• Workout Session Duration – Consider goals for each particular workout; overall program

goals; current client fitness level, and overall weekly training load.

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Acute Training Variables Continued• One of the key acute variables is the Movement Speed Setting which is

controlled via the intensity knob• Slower motor speeds/lower intensity settings allow greater force production and tend

to more quickly fatigue a muscle or muscle group.• However because the movement speed is slow the user ends up performing less

repetitions than at higher speeds which also affects overall exercise intensity and Rate of Perceived Exertion (RPE).

• Higher motor speeds optimize the ability to produce force at higher speeds, but if goals include generating power with significant loads time must be spent working at slower speeds to maximize strength gains as well as sets/workouts done at higher speeds.

• Mixed speed workouts can also be very productive with some done starting with a higher movement speed progressing to a slower movement speed or more commonly starting with lower speed sets followed by higher speed sets.

• Work/Rest Ratio – as with all forms of training the ratio of work time to rest time is a key variable in determining exercise intensity and which energy system/systems are being engaged during an exercise session.

• In general for hypertrophy and endurance a higher work/rest ratio will produce the best results.

• While for maximal strength or power a much lower work/rest ratio will maximize gains.

• This ratio can be managed by doing timed sets with timed recovery or by doing specific number of repetitions per set with a set or variable recovery interval.

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Examples• Program Goal: “Toning and Weight Loss”

– As with hypertrophy focus on relatively high number of sets/reps/exercises and progression in these areas to maximize total work/caloric expenditure

– Use a relatively high work/rest ratio to maximize total work done while maintaining high metabolic intensity. Generally start with a 1:2 ratio and progress as able to 1:1 and eventually higher ratios

– Use varied intensity settings based on exercise selection and too keep client from plateauing – Deliberate heavy use of double concentric movements such as lat pulldown/overhead press

to maximize total work, calories burned and maintain high metabolic output.– Workout duration is only 20 – 30 minutes because this type of programming is metabolically

very intense – Workout Frequency – 2 to a maximum of 3 workouts of this type per week. NOTE: you can

add in other workouts with lower metabolic intensity that focus on Power or Strength more with lower volume, metabolic intensity, and lower work/rest ratios.

• Program Goal: Muscle Hypertrophy– High number of sets, reps and exercises– High work/rest ratio– Varied intensity settings to target and develop different muscle fiber types but more time

spent at moderate to high speed settings corresponding to mid-range to LOW intensity settings to maintain emphasis on high work rate

– Training frequency of 3 – 5 days per week with introduction of split routines focusing on particular muscle group or groups as client progresses

– Workout duration of 30 – 60 minutes

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Examples Continued• Program Goal: Maximal Power Development

– Volume should be kept low with much lower number of sets, repetitions per set, and total exercises per training session to allow for complete recovery between sets to maintain high power output because power development is NOT a fatigue generated adaptive response.

– Work/Rest Ratio will also be kept much lower to allow for complete recovery between sets of exercises. A decent starting point would be 1:2 for initial work/rest ratio but this can and should be adjusted based on athletes performance within the session.

– Movement speed will be kept high most of the time (lower intensity settings) to focus on high movement speed with overload.

– However at least 1 session per week will need to focus on maximal strength development if the ultimate goal includes increased power with high loads!

– Frequency is 1 – 3 sessions per week and each power session should only be done when athlete is in a recovered state to allow for maximum power/force output.

– Duration of workouts can be long because although there are less sets/reps/exercises the greatly decreased work/rest ration increases time between exercise sets.

• Maximum Strength Development – as above accept that the movement speed will be kept low (intensity high) to allow for maximum force generation.

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Bibleography• 1 – Isokinetics In Human Performance, Lee Brown – Editor –

Med, CSCS, Florida Atlantic University, Published by Human Kinetics Copyright 2000; 3 – 4.

• 2 – Tomberline, J.P., J.R. Basford, E.E. Schwen, P.A. Orte, S.C. Scott, R.K. Laughman, and D. M. Ilstrud. 1991 Comparitive Study of isokinetic eccentric and concentric quadriceps training. J of Orthepedic Sports Physical Therapy. 14: 31 – 36.

• 3 – Knapik, J.J., J.E. Wright, R.H. Mawdsley, and J. Braun. 1983. Isometric, isotonic, and isokinetic torque variations in four muscle groups through a range of joint motion. Phys. Therapy 63: 938-47.

• 4 – Bell, G.J., S.R. Peterson, J. Wessel, K. Bagnall, And H.A. Quinney. 1991. Adaptations to endurance and low velocity resistance training performed in sequence. Can J. Sport Sci. 16: 186-92

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Bibleography• 5 – Bell, G.J., and H. Wenger. 1992. Physiological

adaptations to velocity controlled resistance training. Sports Med. 13 (4): 234 – 44

• 6 – Davies, A.H. 1977. Chronic effects of isokinetic and allokinetic training on muscle force, endurance, and muscular hypertrophy. Dissertation Abstracts International. 38: 153A.

• 7 – Ciriello, V.M, W.C. Holden and W.J. Evans. 1983. The effects of two isokinetic training regimens on muscle strength and fiber composition. In Biochemistry Exercise, ed. Knuttgen. H., Vogel, J., and Poortmans, J. 787-93 Champaign, IL: Human Kinetics.

• 8 – Fleck, S. J. and W.J. Kraemer 1997. Designing resistance training programs. 2d Ed. Champaign, IL: Human Kinetics.

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• 9 – Bell, G.J., G.D. Snydmiller, J.P. Beary, and H.A. Quinney. 1989 The effect of high and low velocity resistance training on anaerobic power output in cyclists. J. Hum. Move. Studies 16: 173 – 81.

• 10 – Hinson, M., and J. Rosentswieg. 1973. Coparitive electromyographic values of isometric, isotonic, and isokinetic contraction. Res. Quart. 44(1): 71-78.

• 11 – Lander, J.E., B.T. Bates, J.A. Sawhill, and J.A. Hamill. 1985. Comparison between free weight and isokinetic bench pressing. Med Sci Sports Exerc. 17(3): 344-53.

• 12 – Lacerte, M., B.J. deLateur, A.D. Alquiest, and K.A. Questad. 1992 Concentric verus combined concentric-eccentric isokinetic training programs: Effect on peak torque of human quadriceps femoris muscle. Ach. PHys. Med. Rehab. 73: 1059-62

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• 13 – Mannion, A.F., P.M. Jakemans, and P.L.T. Willan. 1992 Effect of isokinetic training of the knee extensors on isokinetic strength and peak power output during cycling. Eur. J. Appl. Phys. 65: 370-75.

• 14 – Jenkins, W.L., M. Thackaberry, and C. Killlian. 1984. Speed-specific isokinetic training. J. Orth. Sport Phys. Ther 6: 181-83.

• 15 – Fleck, S.J. 1979. Varying frequency and intensity of isokinetic strength training. Dissertation Abstracts International. 39: 2126A.

• 16 – Coyle, E., D.C. Feiring, T.C. Rotkis, R.W. Cote, F.B. Roby, W. Lee, and J.H. Wilmore. 1981 Specificity of power improvements through slow and fast isokinetic traiing. J. Appl. Phys. 51: 1437-42.

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• 17 – Moffroid, M.A. and R.H. Whipple. 1970. Specificity of speed of exercise. Phys. Ther. 50: 1693-99.

• 18 – Kaneshisa, H., and M. Miyashita. 1983. Effects of isometric and isokinetic muscle training on static strength and dynamic power. Eur J. Appl. Phys. 50: 365-71.

• 19 – Behm, D.G., and D.G. Sale. 1993. Intended rather than actual movement velocity determines velocity-specific training response. Sport Med. 15: 374-88

• 20 – Weltman, A., C. Janney, C. Rians, K. Strand, B. Berg, S. Tippit, J. Wise, B. Cahill, and F. Katch. 1986. The effects of hydraulic resistance strength training in pre-pubertal males. Med. Sci, Sport Exerc. 18: 629-38

• 21 – Ellenbecker, T.S., G.J. Davies, and M.J. Rowinski. 1988. Concentric versus eccentric isokinetic strengthening of the rotator cuff. Am. J. Sports Med. 16(1): 64-69.

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• 22 – Pipes, T.V., and J.H. Wilmore. 1975. Isokinetic vs. isotonic strength training in adult men. Med. Sci. Sports 7(4): 262-74.

• 23 – Narici, M.V., G.S. Roi, L. Landoni, A.E. Minetti, and P. Cerretelli. 1989. Changes in force, cross-sectional area, and neural activation during strength training and detraining of the human quadriceps. Eur J. App. Phys. 59:310-19.

• 24 – Moffroid, M.A., and R.H. Whipple, J. Hotkosh, E. Lowman, and H. Thistle. 1969. A study of isokinetic exercise. Phys. Ther. 49: 735-47.

• 25 – Thistle, H.G., H.J. Hislop, M. Moffroid, and E.w. Loman. 1967. Isokinetic contraction: A new concept in resistive exercise. Arch. Phys. Med. Rehab. 48: 279-82.

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• 26 – Page, PA, Lamberth, J, Abedie, B, Boling, R, Collins, R, and Linton, R. 1993 Posterior rotator cuff strengthening using theraband in a functional diagonal pattern in collegiate baseball pitchers. J. Athletic Training 28(4): 346, 348-50, 352-54.

• 27 – Perrin, D.H. 1993. Isokinetic exercise and assessment. Champaign, IL: Human Kinetics.

• 28 – Kovaleski, J.E., and R.J. Heitman. 1993. Interaction of velocity and progression order during isokinetic velocity spectrum exercise. Isokinetics and Exercise Science 3: 118-22.

• 29 – Kovaleski, J.E., and R.J. Heitman. 1993. Effects of isokinetic velocity spectrum exercise on torque production. Sports Medicine, Training, and Rehabilitation 4:67-71

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• 30 – Kovaleski, J.E., R.J. Heitman, F.M. Scaffidi, and F.B. Fondren. 1992. Effects of isokinetic velocity spectrum exercise on average power and total work. Journal of Athletic Training 27: 54-56.