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Applying Biomechanics to Fitness Gains Research

This article first appeared in the October 1983 issue of AB with the headline, “Biomechanics: The New Frontier in Weight Training.”


For the past several years, researchers at major universities around the country and world have been spending an increasing amount of time analyzing weight training and conditioning.

Often in the past, their work hasn’t made it into the hands of those who need it most—those responsible for implementing and supervising weight training programs. And, in many cases, the major purpose of the scientists’ work has been to determine whether equipment A or equipment B did the best job of improving one’s strength.

More recently, though, there has been an expanding focus of significant research especially by those involved in the study of biomechanics. It is shedding light on such new frontiers in weight training as: individualized programs based on a scientific prediction of what an individual should be able to accomplish; new training regimens more closely resembling “interval” training; and predicting the levels and types of forces the joints can handle before injury risks increase.

One of the leaders in biomechanics is Marlene Adrian, Ph.D., newly-appointed head of biomechanics at the University of Illinois. Previously, Adrian was a professor of physical education at Washington State University.

According to Adrian, the three major areas of advancements in biomechanics and weight training can be summarized as follows:

1. More efficient assessment of work and power done, and relating these to the program being studied, rather than merely looking at gains made doing one particular program. This has particular application in developing truly individualized training programs.

2. More biomechanical input into the development of new weight training machines and programs, including the introduction of interval training as a comprehensive method of improving strength and endurance, and minimizing injury.

3. Experimentation in mathematical modeling and film analysis, for the purposes of determining and analyzing the forces placed on the various joints by weight training, and studying how individuals automatically adjust their movement pattern to distribute stress.


What’s the Best Way of Achieving Training Gains?

According to Adrian, a noticeable shift has occurred in the direction of weight training research.

“Most of the previous work has been done basically testing particular programs, and determining whether they produced gains or not. Now, we’re starting to investigate why the gains are being made, and how best to make the gains,” she explained.

“From a biomechanical point of view, the idea is one of trying to more scientifically equate the programs, with respect to work and power, making it much easier to compare the gains and the reasons for the gains—so that one doesn’t merely say that a program is better than another program, when the programs are completely unequal in terms of work involved.

“It’s an assessment of mechanical work and power, in order to equate the different test programs, rather than to merely look at the gains accomplished using different types of programs.”

Adrian gives this example of how “work” and “power” are now being studied—in terms of the load being lifted, and the distance that it is being lifted.

“Let’s say you have a person lift 50 pounds, 10 times. If you have everyone else doing that—50 pounds, 10 times—you’d think everybody’s doing the same thing. That’s not true. If a person has longer arms, they’re doing more work than the person with short arms, because they’re lifting the weight a longer distance each time.

“We have not yet done enough work on the whole idea of individualization (of training programs). We tell everybody to lift 10 times, do 10 push-ups, 20 sit-ups, etc. Yet every time they’re lifting something, including their own body weight, people with different body sizes will lift things different distances.”

Adrian predicts that the age of truly individualized weight training programs is coming—slowly. One reason they haven’t come out yet, she says, is because “It’s far too complicated. Too many people want the cookbook, the easy way.

“My opinion is that with the use of the computer, we’re going to be able to feed in the anthrometric data—body size and shape, muscle girth, length of levers—an estimation of who that body is that’s doing the work. And then the goals can be set up more on an individual basis.”

Eventually, she says, “We might be able to predict what the person ought to be able to do, based on the information we’ve entered on the body itself.”


Biomechanics Input into Development of Equipment

One major advancement that is already evident is that many weight training devices have been tested or developed by biomechanics people. They are trying to develop machines that will do a more complete kind of a program, combining some of the benefits of one type of system with another.

Along with that, Adrian says, there is more effort to scientifically “cover” the entire body—to develop machines to work more muscle groups than previously. “There are some muscles we really have forgotten. By looking at all the different ways the body can move, we find ways to develop all the muscles of the body,” she said.

By far the most novel contribution of biomechanics people is the development of programs for using the various weight training systems. Prime among these, says Adrian, is the concept of interval training, similar to interval training for runners.

Instead of having someone start with 10 repetitions this week, then go to 20, then 30; or staying with 10 reps throughout and increasing the weight, researchers are toying with programs whereby the lifter might, in this order:

  • increase the load;
  • increase the frequency;
  • increase both load and frequency;
  • decrease one or the other, or both;
  • then increase again then decrease, etc.

“It involves doing a little bit more changing of intensities, durations and numbers of repetitions, in different ways, to try to get a more comprehensive strength and endurance program—one that will make greater gains, and avoid some of the ‘staleness’ and muscle soreness that might otherwise take place,” says Adrian.

“It’s just in its infancy stage right now, but things are happening.”


What Limits Are We Taking the Body To?

The final area of advancement, says Adrian, is mathematical modeling techniques, film analysis and other types of evaluation of the forces of weight training.

Their purpose, she says, is to “try to actually determine what are some of the reactive forces at the joints—moments of force, torsion, or torque at the joint. And trying then to estimate, given a certain situation, how a person performing the activity reacts; how dangerous it could be, and what are some of the basic possibilities of potential injury at different joints.”

Such work utilizes the computer, basic mathematical assumptions, film analysis or force platform analysis, and sometimes even force transducers, placed on the hands.

By measuring forces, acceleration rates, etc., and using mathematical modeling and simulation, it’s possible to estimate not only what the forces are at the joints themselves, but what would be the kind of training that needs to be developed in specific situations, and what limits we’re taking the human body to.

Although there is a fair amount of published research in this area, Adrian says, “we need much more individualized data.

“We can’t just say, if I lift 20 pounds, then 30, then 40, that my muscle effort is going to increase proportionally with the weight. This does not happen. Research has shown that the speed at which you lift, as well as the load, is going to change how we actually perform the lift.

“In other words, as the load changes, we sometimes change how much we flex at the hip joint, how much we lean over with the trunk. People make different adjustments, and when the loads get heavier, they may adjust their body and transfer the muscle forces and efforts at different joints, to protect the most vulnerable joints,” she explained.

“They change the whole movement, so you can’t say the load will go proportionally at the knee joint, and will produce greater and greater forces at the knee joint, and be more dangerous. Because the lifter may immediately transfer some of that load to the hip joint or the back therefore making the lift easier on the knee joint.

“You can’t just make the assumption that if you increase the load, you’ll increase the benefits for a particular muscle group, because the lifter will change their movement patterns. And they change them individually; we don’t have enough data to say there’s a common way that they change.”

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