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by Dr David Costill

March 23, 1993

Increasing arm strength in the pool

It has been estimated that more than half of one's success in sprint swimming is dependent upon upper body strength. At distances from 50 to 500 yards freestyle, the individual who has the greatest strength during the pull is able to overcome more of the drag created by his/her body.

In 1982 and '83 we tested the arm strength of 40 college and 60 Masters swimmers and found that we could accurately predict how fast they could swim the 50 to 500 yard freestyle events.

We have two ways to test the upper body strength, the first being performed out of the water using a Biokinetic Swim Bench, which allows the swimmer to simulate the pulling phase of the arm stroke. Though this test measures the strength of the muscles used during swimming, it fails to reflect the forces that can be exerted on the water while swimming.

For that reason we developed a second testing system that enabled us to record the swimmers' power in the water. Masters swimmers who have the highest swimming power also have the fastest time for a 25 yard sprint. To put it another way, if you are slow in a sprint, you probably have little arm strength and power.

What factors determine one's strength? The ability to exert force against the water appears to be dictated by (1) the size of your muscles, and (2) your ability to use that strength effectively. The number and size of the muscle cells in your upper arm and shoulders determine, to a large degree, the amount of force you can apply to the water with your hand and forearm. Unfortunately, as we grow older the body tends to reduce the muscle cell size, and to discard those muscle fibers that are not used regularly. Strength and swimming training, on the other hand, tend to slow this loss of muscle mass. It should be pointed out that the body has special hormones (e.g., testosterone) that enable the muscles to retain protein and grow bigger. These hormones are lower in females than in males, which partly explains the gender difference in muscle size and freestyle sprinting ability.

Having big muscles does not guarantee that you will be a good freestyle swimmer. If you are unable to use your strength effectively, then no amount of training will make you faster. We see this most often when we test triathletes who are strong and highly-trained, but lack the skills of a competitive swimmer. Their time and attention would better be spent on improving their swimming mechanics than on strength training.

Who benefits from strength training? Individuals who are subpar in upper body strength will certainly benefit from training that is geared toward maximal contractions (i.e., weight lifting and sprint swimming). The only way to know for certain if you are "subpar in strength" is to be tested, but that may be unnecessary. Whether you are strong or weak, you still need to contract the muscle with maximal effort during training in order to maintain or improve you swimming strength.

But is lifting weights the only way to improve strength? Probably not! There are three rules to follow when it comes to optimizing swimming strength and power.

First, the muscle must repeatedly contract with maximal force.

Second, the actions performed during these contractions should mimic the motions used in swimming. Our studies with college swimmers has clearly shown that swimming strength can best be achieved by doing power training in the pool. When you do a sprint workout, the muscles contract with maximal force and in a manner that is specific to the skill you are trying to develop.

The third rule relates to the number of sprints performed in each set and how many times each week you need to do this type of training. Though this point seems to vary from person to person, it is my impression that performing a set (5 to 10) of 25 to 50 yard sprints, with relatively long rest, two to three times per week, is sufficient to optimize freestyle sprinting strength. As with any strength training program, maximal muscle contractions are exhaustive. Consequently, these sprints should be repeated only so long as you can maintain good mechanics. Typical sprint/strength-oriented sets might be as follows:

10 to 20 times 25 yard sprints with 30 seconds rest, or
5 to 10 times 50 yard sprint with 1 to 2 minutes rest

Though we recognize that arm strength is only one of the determinants of success in swimming, it is one that the factors that can be improved with a well-designed training program.

Dr. David Costill is the director of Ball State University's Human Performance Laboratory and is current chairman of the USMS Sports Medicine, Health and Safety Committee. A Masters swimmer for the past 12 years, he has won numerous national freestyle and individual medley championships.


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