Muscles by Micro
The Computerized Exercise Machine has
added a sophisticated dimension to strength
training.
by Reginald D. Gates
C e.nturies ago, Milo the Wrestler was the first to use progressive resistance exercises to improve his performance. Legend says that he became able to lift an ox by lifting a baby calf each day until the calf reached its full growth. Since then, many advances have been made in our ability to develop muscular strength -- isotonic. ' isometric, and hiokinetic approaches all have their place. Now, work at the Coto Research Center in Southern California enables modern coaches to use a micro-computer to maximize the strength-training,-program for their teams.
The Computerized Exercise Machine (CEM) was developed at the centre under the guidance of Gideon Ariel, a former Olympic competitor (1960 and 1964) and chairman of the United States Olympic Committee on Computer Sciences and Biomechanics. It represents more than 10 years of effort to perfect an exercise machine that can function equally well as a diagnostic tool or a training device. The resulting device is designed to interact with the athlete and provide the user (and coach) with immediate feedback on the results of the exercise.
There are two versions of the
CEM, as shown in the illustrations. One is a chair-like device that is used for "leg" and "arm" work and the other resembles a large han
dlebar mounted above an adjustable curls, etc.
padded bench. The "handlebar"
machine is used to perform ex- ercises can be performed using ercises such as bench presses. lifts these two units. In each device, the or squats. Almost 70 different ex- resistance that works against the
20 Coaching Review
The "Handlebar" Unit is used for bench presses. frill squats, incline presses,
athlete's muscles is supplied by a hydraulic mechanism controlled by a micro-computer.
The computer senses the position and movement of the machine thousands of times a second via a special set of electronic "black boxes", and varies the resistance opposing the athlete by adjusting the hydraulic pressure through another set of electronic devices. This ability to dynamically sense and control the resistance during an exercise is the heart of the CEM. The machine can provide any pattern of resistance desired, varied according to both force and time. Dr. David Costill of the Human Performance Laboratory at Ball State University in Indiana says. "Its capability to be programmed for a variety of isometric, isotonic, biokinetic, and progressive resistance protocols is a unique quality found in no other form of equipment for muscular development".
The advantage of this approach can he seen best via an example. Suppose one of your players can bench press 90 kilograms using free weights. It's important to realize this this 90 kg. does not represent the maximum force that lie can exert at every point in the exercise -- it represent; the maximum that he can lift at his weakest point. The weakest point (in this case) is at the start, since that's where the biomechanical arrangement of his arms, hands, and shoulders give him the least leverage. At the point where he is the strongest biomechanically, the player may be able to exert 140 kg. of force.
After training for six weeks the player can now press 110 kg. He has increased his "minimum" by 25 per cent, but has he increased his niaximuni by 25 per cent, i.e., can he now exert a maximum force of 137.5 kg.? The answer is no. The player has increased his maximum some, since some of the same muscles are involved, but he did not stress his maximum beyond the "old" limit of 140 kg. He did not get nearly the same benefit from the training as measured by comparing the increase at the minimum to the increase at the maximum.
Using the CEM first as a diagnostic tool, we can find out the maximunl amount of force the player can exert at each point in the exercise. CEM is then instructed to train the athlete by varying the resistance so that at the weakest point the resistance is 90 kg. and at the strongest it's 140 kg. All positions,
both weak and strong. are overlooked and development occurs much more rapidly. if the force expended is graphed as a function of time, it would appear as shown in Figure I. The straight line shows the free weight force as a constant. while the curve shows the force exerted using the CEM.
With the CEM, the resistance may also be varied with time, in intervals as small as one hundreth of a second. This means that it doesn't matter how fast or slow you do an exercise using the CEM -- the computer adjusts accordingly. If you wish to train volleyball players to increase their height in the vertical jump. (as has been done with the U.S. Olympic women's volleyball team), you have several options. 1. Train the players using slow halfsquats to increase their strength at each "position" in the movement. 2. Train them with very rapid halfsquats, adjusting the CEM to their speed and overloading them slightly at each position during the exercise. 3. Put a "sticking point" in the squat at their weakest point, so that the CEM holds them at that point for three seconds to let their muscles
develop isometrically, and then let them complete the exercise.
4. Have them repeat rapid halfsquats until the total force during the most recent half-squat is fifty per cent of the force expended during the first repetition.: his is known as fatigue sensitive training. In fact, you could train different players using different approaches and then use the CEM to evaluate which method gave the "best" results.
According to Danny Saar, research done at the Coto Center shows that using CEM not only develops muscular strength but also produces better aerobic training than other methods. During one project they trained four groups as follows. Group I did a fixed amount of work on the CEM. Group 2 exercised on the machine until they reached a 50 per cent fatigue level. Group 3 jogged for 45 minutes (about 10 kilometres), and Group 4 was the control group and did nothing. When the groups were tested using a standard set of non-machine exercises. Group I improved 28 per cent in aerobic capacity in relation to the control group. Group 2 im
Coaching Review 21
140
Illustration I CEM Unit
90
Free Weights
45
I ? 3 4
Duration (in seconds)
Typical force curves for a bench press using free weights vs. a bench press on the Computerized Exercise Machine (CEM ). The CEM will resist the user with the maximum "weight" he can lift at each point during the press. When the biomechanical arrangement of his body permits the user to exert more force, CEM increases its resistance.
proved 33 per cent and Group 3 (the joggers) improved 19 per cent. Interestingly, Group 3 actually decreased in muscle strength during the project. Dr. R.A. Berger of Temple University concurs with their findings and reports. "... work can he uninterrupted between lifts so that no recovery occurs. As a result. the stress on the circulatory system is maintained".
One of the best features of the CEM is that it is designed to give the user immediate audio and visual feedback on their performance. The computer produces a color bar chart display on a monitor visable to the athlete during the exercise. The user can tell at a glance the amount of work done (e.g.. the number of repetitions) andd see the force expended versus the desired force pattern. In addition, an audio signal is produced by the computer at the completion of each movement and at the completion of a set. The computer stores the results of each set and can produce a printout comparing today's results against the previous results for the same set. This provides an objective record of progress in training, that can he reviewed at any time.
One of the obvious uses of the comparative ability of C:EM is in diagnosis and rehabilitation, where the normal force pattern or the force pattern for the athlete prior to the injury is compared to the results after rehabilitation. The CEM can also he used to measure the effectiveness of one training regimen over another. In this connection, the Canadian Forces Base t)ownsview. Ontario have purchased two units to he used for diagnosis in their research work.
The comparison ability of the
CEM also permits it to be used in insurance invest igat ions. A person suspected of "faking" a shoulder injury is asked to repeat certain exercises with the CEM, using minimal force to determine the range of motion. With a real injury, the "shape" of the force pattern is almost identical for each repetition. since it depends upon a biomechan
ical factor. For a fake. the pattern The nrm and Leggy (Ini1. Is used 10r leg extensions and jlesicms, and exercises
shows wide variations as the subject involving the cams (e ., '. ..loremin curls).
tries to imitate what he did on the
previous repetition.
The Coto Research personnel them. All types of exercise have program for your team, the Cornemphasize that the CEM is an their place in the training program puterized Exercise Machine has advancement on previous training (and their proponents). However, definite advantages that should be methods. not a replacement for when evaluating the total training considered.
22 Coaching Review
F/E:__100 ___342
Y R E C D L Y EI 1 536 : 370
! FL 1 546 : 466
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Y P F: TIME EI 1 346 1 360
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� PERFORMANCE PROFILE REPORT _09/15/83__;
� USER: J.WISE
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� TEST DATE: 09/12/83 $
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The Coto Research Center is located in Trabuco Canyon, midway between Los Angeles and San Diego in Southern California. The center provides biomechanical analysis using a variety of machines and techniques, including the Kistler Force Platform and the Selspot 11 system. as well as the Computerized Exerise Machine. They have analyzed many Olympic teams for coaches in the United States and other countries such as Germany. England. France. Italy and Spain. The sports involved included swimming. gymnastics. cycling. fencing. volleyball and diving.
The Computerized Exercise Machine is built around the Radio Shack. Color Computer. modified to provide the electronic interface to the hydraulic components. The computer can be used for other purposes. e.g., scheduling. budgets, and inventory tracking using the wide variety of software available for this personal computer, A complete exercise unit costs approximately $15,000.
An in-depth discussion of the theory behind the Computerized Exercise Machine is found in the article "Resistive Training", published in Clinics in Sports Medicine. Vol. 2 No. I . March 1983. The article was written by Gideon Ariel and contains an extensive bibliography on strength training.
The Pertornianee Profile Report contains a Iyealth o/ daui regarding thelei e.iiensio,zs done by ./i,n Wise. For ev(:In/)le ii' u'e look crrthe average polrer row. Ire can see that his right /e,L' is approximately 50 per cent stronger than the 7ee%t in extensions using (134 kg. (165 lb.) it-eight. Hou�ei er. t/re /1e.tion readings (ir�e appro.virnately the same. This men� indicate an over-development (perhaps a ri,J ht-bonded shot-pictter:' 1 or all in1.ur v 1o the left leg. 0/ course, multiple readings nnrst be e'veditatcel before an) -final determination is made.
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Coaching Review 23
