In other words, to win an Olympic gold medal, the lifter must raise the barbell with more weight than the competitors. To accomplish this task, the knee joint motion must produce more force components in the vertical direction and minimize those in the horizontal direction.
To evaluate the forces on the knee, the most important information can be gleaned by calculating the moment arm. As the knee bends, the moment arm changes.
The goal is to minimize the shear force and maximize the vertical force component and quantification of the moment arm is particularly useful for this purpose. The changes in the moment arm of the joint should be considered when designing exercise equipment. Another vulnerable part of the body which is routinely exposed to shearing forces is in the lower back region between the fourth and fifth lumbar vertebrates.
For all of us who walk on two legs and also lift and carry packages, there is a risk of lower back pain and injury. For decades, there has been continued interest in the prevalence and etiology of lower back pain in industrial applications, injuries in the home, and sport-related problems. Back injuries are commonly associated with the lifting of weights.
Almost any weight lifting exercise, executed while standing with erect posture, is associated with great force on the vertebrate column. Researchers found a high incidence of scoliosis, prolapsed disc, and other injuries to the vertebral column and its associated structures in competitive weight lifters.
The risk of degenerative and traumatic lesions of the spine is not confined to those engaged in competitive lifting as athletes in many different sports routinely incorporate weight training as part of their training routines.
Young and inexperienced lifters represent another high-risk population. In a study of pressures in the trunk cavities when pulling, pushing, and lifting, it was found that with increased stress on the vertebral column, the abdominal muscles are very active in relieving the load on the lumbar spine.
Thus, the abdominal muscles counteract the shearing force to a certain extent. This factor illustrates the importance of well-developed abdominal musculature to aid in the prevention of low-back pain in weight lifting. The widespread use of the "waist belt" among weight lifters is not worn to support the back as many people believe. In , there were no exercise equipment companies familiar with biomechanical calculations or with the ability to design their products to accommodate the dynamically necessary changes.
Many manufacturers may have thought about the need to improve their designs but they did not have the data to actually build new equipment. It was, therefore, a unique situation to be approached by a major exercise manufacturer to help them design better equipment. It was another indicator of the creative and open-mindedness of Harold Zinkin of Universal Gym. He had been an innovator during his earlier years on Muscle Beach and now he was thinking of the future by seeking biomechanical improvements in his line of exercise equipment.
These exercise machines utilized an appropriate resistance lever arm in accordance with the requirements of kinesiology, human anatomy, and were based on dynamically quantified biomechanical information. The design automatically determined the moment of force in each exercise and simultaneously considered the muscular and the dynamic forces due to the motion. Following these biomechanical analyses, we designed a new system which was able to change the resistance for each separate exercise according to the dynamic needs of the person exercising.
In , Universal Gym introduced some of the DVR machines which incorporated the research and development biomechanical analyses which we had designed at CBA. Here are some of the new, scientifically designed equipment:. Bench press machine. The Universal variable resistance bench press station demonstrated an automatic loading effect enabling total muscle training throughout the range of motion because of the cam-bar arrangement.
Leg press and shoulder press stations. These new variable resistance leg and shoulder press stations optimized the resultant force in the appropriate direction and at the same time minimized the shearing force. As discussed previously, a shearing force represents the intra-articular stress on the joint. The unique development of the leg machine was to eliminate standing posture when executing the exercises. The exercise is performed while seated and the legs are exercised against a resistance applied in the horizontal direction.
By providing good support for the back, the press is executed on a seat with the motion restricted to both suit the exercise and, at the same time, to minimize the shearing factor. Thus, high shear forces on the lumbar region are eliminated. For nearly all of the newly designed Universal equipment, the total muscular performance exceeded 85 percent of maximum muscular movement involvement throughout the range of motion.
This extended range of motion permitted maximum training for each muscular group involved. After Universal Gym introduced the first few DVR machines and explained the biomechanical principles which I had taught them, the reaction from their competitors was immediate and fierce. I realized how difficult it must have been for Galileo when the soldiers locked him out of his house for telling the world his calculations indicated that the Sun rotated around the Earth. I am not trying to compare myself to Galileo, who was one of the greatest scientists of the last years.
But, rather that we had each done something that was correct but revolutionary for its time. By and for years after, thousands of Universal Gym machines were sold around the globe. Universal hired CBA to send me around the World to present my research at various conferences. We both benefited from this relationship since they received publicity by a well-known biomechanist and I was able to present the CBA technology in conference settings.
My personal goal was to attract companies interested in our quantification technologies who would hire us to perform work on their products. We already had a proven track record of positive results and this was a wonderful opportunity to present us in favorable settings. I had never heard of Arthur Jones before that article was published but he blasted into my world like the meteorite that smashed into the Yucatan peninsula 65 million years ago contributing to the end of the dinosaurs.
Fortunately, Arthur Jones was more prehistoric than I. Journal Athletic The strategy was working well until one day when, unexpectedly, an article was published in the. Cover and first page of article. I soon discovered that Arthur Jones was the owner and the founder of the Nautilus Company.
Nautilus was a major commercial competitor of Universal. The article was seven pages in length and hurled many outlandish claims against both Universal and me. Jones was allegedly a wild character in his own right. The claim was that he always carried a gun and, according to urban legend, he had pistol-whipped people when he was provoked. He owned two airplanes which he used to fly his exercise equipment units from their manufacturing base in Columbia to the US for sale.
It was a popular show in America because it showed daring and exciting rescues of African animals which were in danger from situations such as environmental threats or poachers.
After he had left Africa, he returned to a small town in Florida, Lake Helen, where he had based his Nautilus Company. He had a collection of unusual pets including snakes, spiders, quails, and a big crocodile named Jack.
To the best of my knowledge, Jones never finished elementary school and, most certainly, had no advanced academic education whatsoever. Unfortunately, his machines were massive and extremely well made but were exactly backwards for the purpose of dynamic strength development. The machines had to be used at a slow, deliberate speed.
If the exerciser tried to move quickly, enormous inertia was generated which caused the weight stack to move upward rapidly. The result was that the exerciser could develop hypertrophy but not strength for dynamic athletic activities. Athletic activities require fitness training to be dynamic rather than slow and steady.
Nautilus equipment was fine for some activities but not for sports training. I did not meet him at that time but it was reported that he was extremely angry. The stories of his ranting and raving eventually became legendary. After the show, Jones began his attack on me and on Universal. However, I will present the statements that are relevant to this story. Journal Athletic In his. Think it is about time for somebody to make some very plain statements As well as utterly false claims and phony documentation.
Trying to "prove" their lies on the basis of research that never occurred. The field of exercise has been almost literally knee-deep in outright criminal fraud for the last thirty years The problem has been [and the problem remains] How do you know what to believe?
Or not to believe? The last was a good question, but one he forgot to ask himself. He was clearly entitled to his attitudes, ideas, and concepts although I did not agree with most of them. This is a free country and you are allowed to believe whatever you want to believe.
However, some of his complaints were probably hyperbole but they made him feel good to expound on them. But his personal and unjustified attacks on me and Universal were wrong, scientifically incorrect, and a mirror-image of his own claims. Ed Burke is a liar and, in due course, we will prove it in court; with a long list of witnesses that will put him in jail where he belongs Although he had not thrown far enough to win an Olympic medal, he remained the US champion.
Long after the events described here with Arthur Jones, Ed Burke resumed his training and decided to compete in the Los Angeles Olympics. He received the great honor of being elected by all of the American athletes to carry the flag as he led all of them into the Stadium in the Games Opening Ceremony.
In , Ed had been working for Universal for many years and I worked with him at shows presenting the Universal machines. Since I spent time with both of them over the years, I can say without dispute, that Ed Burke was and is an honorable, honest person. I cannot say the same about Arthur Jones.
Ed Burke in the Olympics. Which variable resistance, of course, was "exactly correct. Well the facts are that Gideon Ariel is an outright fraud When I first saw their initial ads, concerning the new Centurion line of Universal machines that supposedly provided variable resistance, I simply could not figure out how it was supposed to VARY. So I approached the great doctor, Gideon Ariel, and I asked him I said, "Tell me in figures, so a dumb guy like me can understand.
What percentage does it increase? Then I offered to bet him a thousand dollars that his machine didn't vary at all, that the resistance remained absolutely constant in every position. He refused to bet. If he really believed his statements, then he was almost unbelievably stupid. And if he was aware that his statements were lies, then he was guilty of criminal fraud. Take your pick; there is no other choice, fool or fraud.
Jones was right. He did not understand how the mechanism worked on the DVR machines. His ignorance and outrageous hatred was staggering.
The most amazing part of the entire attack was that he was wrong about all of his scientific claims and, therefore, guilty of exactly what he was accusing others of doing or being. At this point, I should not have been surprised to read that one of my old adversaries from the University of Massachusetts, Dr. Plagenhoef, would come back to haunt me through the distorted lens of Arthur Jones. I invited Professor Stan Plagenhoef of the University of Massachusetts to come to the Trainers convention in Kansas City for the purpose of confronting the great doctor Ariel.
Professor Plagenhoef, you see, was Gideon's former teacher Then I said Plagenhoef, stood up for you And he assured me that you were For your part, be you coach, trainer, doctor or athlete I was not surprised that my old adversary, Dr.
Plagenhoef, was attacking me even with the likes of Arthur Jones. What did shock me was that my Professor, the one who had taught me biomechanics and accused me of not knowing enough about engineering to have my own company, was unable to understand how the mechanism that I had devised for the Universal machine varied the resistance.
An engineering professor of mine, Paul Tartaglia, and I had designed a sleeve mechanism which we attached to the bar. This mechanism consisted of a roller that always applied the force perpendicular to the bar. What this accomplished was that when the bar was pushed, the moment arm became longer and the resistance increased. A diagram illustrating this system is shown below:.
It was understandable that Arthur Jones did not have sufficient engineering education to make the appropriate calculations to realize the force applications made possible by the DVR mechanism. But when Professor Plagenhoef was unable to make the correct assessment, I could only surmise that he did not want to recognize the simplicity and cleverness of the device.
Based on the accusations, despite the craziness of source, we concluded that it would be a good strategy to have the machines tested by an independent professional testing equipment company. One of the leading companies for this task was Truesdail Laboratories. I was familiar with the company since they had been instrumental previously in the Johnny Carson case. Truesdail Laboratories agreed to test the equipment and provide detailed results.
Universal provided the machines for testing with the specific purpose to determine whether they varied in resistance as I had calculated. There was no question that the resistance changed. However, the primary issues were the accuracy of my calculations and the functionality of the equipment to perform as desired.
The machines did, indeed, vary as the person exercised exactly as they had been advertised to do. Now, Universal had an independent third-party confirmation regarding their claims.
Step one was to print and circulate the Truesdail results in a handout available at all of the trade shows. The cover of this brochure is shown below and the text is available in its entirety in the appendix.
After the Truesdail results had been published, Harold Zinkin again asked me to come to Fresno as soon as possible. Cliff had served in the US Marines in Vietnam and was a war hero with chest covered with medals.
On the way to the Universal office, Cliff told me that Universal was launching an incredibly important project and that he had been selected to head this initiative. I was pleased to hear that Cliff was going to be placed in a leadership role. For the past several years, I had come to know him and was very impressed with his abilities as a planner and leader. Harold Zinkin sat at the head of the conference table with one of the Universal engineers, Dennis Kiser, their sales manager, Ed Burke, and the president of Universal, Chuck Cocker.
Cliff Coker, the head of research and development, and I sat down at the table and all eyes focused on Harold. I imagined that this environment must be what every campaign resembles before the combat begins. Universal is going to file a multimillion dollar lawsuit against the Nautilus Corporation and individually against Arthur Jones. We want to know specifically and scientifically what the Nautilus machines actually do with regard to their claims of providing resistance as well as whether the other performance parameters they claim are correct.
We will send an official request directing you to conduct this research see appendix. This project required some subterfuge, though. We had to take films of the machines without alerting Arthur Jones or any of his sales staff.
Fortunately, Ed Burke and Cliff Coker had many contacts in the exercise and fitness world so they were able to find all of the Nautilus equipment which we were able to film. After we had the film, it was business as usual, biomechanically speaking. We used all of the CBA equipment, personnel, and technology to evaluate how the Nautilus machines performed. After we had the data on the Nautilus, we compared them with the Universal Machines.
CBA provided a detailed, in-depth report to Universal Gym. The report included details about each Nautilus machine and a specific comparison with the appropriate Universal equipment. It was lengthy and filled with scientifically calculated biomechanical results obtained under dynamic conditions.
Following the receipt of the report from CBA, Universal prepared a large brochure to detail the findings we had made. Needless to say, the DVR on the Universal equipment provided more resistance throughout more of the exercise stroke. These strengths were specifically identified. For the Nautilus machines, on the contrary, the limitations were shown in detail. The message presented in the section was to make it clear that any resistance which a muscle had to overcome would be beneficial in the development of muscular force.
There were differences of opinions between the two companies with regard to training principles and the relative effectiveness.
There are two types of muscular contractions within the human body: concentric and eccentric. Concentric contractions are when the muscles pull one limb segment towards another which reduces the angle between the two segments. With concentric contractions, the muscle becomes shorter. For example, holding a weight in the hand and moving the arm so that the forearm moves upwards towards the upper arm will reduce the internal angle at the elbow.
Eccentric contractions are the opposite movements. The muscle lengthens and the angle between the segments increases in size. Holding a weight in the hand, with the weight touching the upper arm, an eccentric contraction would lower the lower arm resulting in increasing the internal angle at the elbow.
Daily life activities and sports are all blends of these two types of muscle contractions. Walking is an excellent example which requires bending and flexing of the leg joints, the stabilization of the torso, and balance is assisted with arm motions. Exercise training can focus on many levels. Many people are merely trying to produce strength for a healthy daily life while others are attempting to win Olympic medals or achieve other maximum goals. There were major differences between Universal and Nautilus to achieve these varying goals.
The philosophy of their training principles and the relative conditioning effectiveness had the same ultimate goal of strength development and fitness. The manner and construction of the equipment for each significantly effected how they attempted to accomplish these training goals.
One of the most obvious differences was the emphasis on concentric positive force with the Universal equipment compared to the heavier reliance on eccentric negative force with Nautilus. This was manifested primarily through the construction of the machines.
Universal employed the DVR device which allowed the exerciser to maximize the concentric contraction throughout most of the exercise stroke. Nautilus advocated negative resistive training or eccentric motion and they recommended slow movements in both directions.
It is unknown whether the slow speed was recommended because of the belief that strength was developed most readily with this exercise technique or rather that slowness was necessary because of the equipment design.
The design of the equipment of the weight stack and cam arrangement on the Nautilus equipment precluded rapid movements. The result was that very little initial effort resulted in large displacement of the weights. In order to exercise more of the musculature, the exercise action had to be slow so that the weights were moved by the person rather than by inertia. Negative resistance training, that is eccentric, is simply the exertion of maximum muscular effort while lowering a weight from the extended or ending position back to its original starting point.
In the previous example, when the weight in the hand was lifted up to touch the upper arm bicep curl this constituted the concentric portion of the exercise. Returning the weight downwards to the starting point would be the eccentric phase of the exercise.
Although there is a natural muscular system of concentric-eccentric action, Nautilus placed greater emphasis on the lowering or negative phase of the movement. Furthermore, the performance which they espoused was to execute the exercise strokes, in both directions, with slow, controlled speed.
Arguments have continued, before and after that time, concerning the efficacy of concentration on eccentric contractions for athletic achievements. There appears to be no scientific basis that training in a negative or eccentric fashion will improve the strength for athletic performance.
There does seem to be more bases for training all of the muscles for dynamic, or explosive, performances. Athletic events are primarily concerned with the development of "Functional Strength. In other words, the athlete should be able to generate the maximum amount of force at every point of the movement rather than slowly under control.
Negative training over a long period of time may actually produce impaired coordination as well as a reduction in athletic ballistic efficiency speed of the movement.
There may as well be reductions in the biochemical activities within the muscle although this remains to be proven.
Every athletic activity has its own unique muscular demands. For example, some activities may require greater leg strength while others require greater arm strength.
In addition, they also may differ in the direction in which the force is applied. In general, a high jumper needs more leg strength to be applied while a long jumper requires greater leg strength for translation in a horizontal direction.
Each of these jumping events requires leg strength but the performance criteria for each event are different. Strength development must be developed appropriately in conjunction with the correct performance technique. The ability to exert a maximum force at only one isolated joint angle, such as with an isometric contraction, has no bearing on the efficiency of either of these sporting performance. It would appear rather obvious that maximum athletic performances cannot be achieved through negative training, isometric programs, or exercising all athletes with the same fitness protocols.
The advantage that the Universal DVR equipment was that the exercise motions more nearly reflected the anatomical and neurological system in the human. There was a natural lifting ratio was maintained while the resistive intensity instantaneously adjusted to accommodate the mechanical changes. The adaptive mechanism which the DVR provided, allowed for maximum muscular efforts throughout the entire range in motion.
I had maintained confidence in the calculations that CBA and the Universal engineers had made and in the product that had resulted from them. But it was wonderful that an external, unbiased third party had made it official. Eventually, the report reached Arthur Jones. Apparently, his response was rapid. His urgent communications to Universal reflected an obvious desperation since his previous behavior was nothing if not belligerent. He asked me to come as soon as possible to Fresno in order to discuss the future steps regarding Arthur Jones.
The next day I was once again flying for hours across America to meet about Arthur Jones and Nautilus. This was prior to the long lines and extensive security checks so the length of time was spent flying.
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Offers is valid once to a customer and excludes previously placed orders. Offers are not valid at retail stores or outlets. Offers valid for a limited time only. Menu Close Homepage. The free weights area is full of big, grunting men which can be intimidating while the machines are being hogged by Lycra-clad women doing strange leg movements.
But which is best for you? We take a look. There is a significant difference between free weights and resistance machines, both in how they work and the results they will give you. The free weights are the barbells and dumbbells in the gym, while the machines are any resistance-based workout machines such as the leg press, assisted chin up machine, or lat pull down. There are two types of resistance machine: plate loaded and pin loaded.
The plate loaded machines work by the user adding weighted plates to a stack in order to increase the resistance. This can be tricky if it's a busy gym as you may struggle to find the plates that you want and the weight cannot be changed easily. Pin loaded machines have a stack of weights already part of the machine and the user changes the resistance by simply moving a pin up or down. This is better for working on pyramid sets or drop sets when you need to change the weight quickly, and means you don't need to leave the machine in order to change the weight resistance.
The primary difference between free weights and machines is that machines are fixed in place and only move in certain directions whereas free weights can be moved in any way the user chooses. Free weights force you to use more stabiliser muscles in order to control the weight, whereas resistance machines can help you with the move by keeping you in place. In general, free weights activate more muscles than machines and therefore are better for building muscle in the long-run.
However, towards the end of your session when your muscles are tired and your form is starting to suffer, machines are safer and can help you to continue training safely. Not only this, machines can help you to train weaker muscles more safely and help them to get as strong as your dominant areas. For example, a squat is a free weight exercise. However, if you are quad-dominant, your hamstrings will start to lag behind. Therefore, you could use the hamstring curl machine after doing your squat sets in order to target your hamstrings separately.
The best way to build muscle is to use free weights for most of your workout and then use the machines for accessory exercises.
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