Resistance to Aquatic Motion

Most of a swimmer’s energy is used to overcome resistance. Even world-class swimmers spend more than 90 percent of their swimming energy overcoming resistance, and less than 10 percent translates into forward motion. For less accomplished swimmers, as little as 2 percent of expended effort yields forward progress. Much of your swimming improvement will come from learning how to combat (or, more accurately, avoid) several types of resistance. To do this, though, you need to understand more about resistance and about the general strategies you’ll employ to minimize its effects.

External Resistance

Because water is roughly 800 times denser than air, it offers strong resistance to a body moving through it. There are three major types of resistance, or drag, acting on a swimmer: form drag, wave drag, and surface drag. Form drag is the resistance that results from the shape of an object moving through the water (figure 4.1a). Reducing the front surface area that meets the oncoming water reduces form drag (figure 4.1b). This means always keeping the body balanced as close to horizontal as possible, as well as keeping it long and narrow, while swimming. It also means eliminating unnecessary motions. If you are perfectly streamlined, any motion you make increases form drag, so avoid any movement other than the minimum necessary to propel yourself. Just as a boat builder shapes long, tapered hulls instead of flat, square hulls for a racing boat, you want to taper the form and profile of your body for traveling through the water—and you want to maintain that form as you swim. A swimmer who understands and applies the concepts of balance and streamlining can dramatically reduce form drag.

Wave drag is the result of creating a wake. For the body to move forward through the surface of the water, it must move water out of the way. This creates a wave that travels away from the body. Cutting a wider path through the surface means that the water must be pushed further and faster to get it out of the way, which creates a bigger wave. The bigger the wave, the more energy the swimmer gives away to the water. In freestyle, you try to cut a narrow path through the surface by maximizing the time you spend on the sides of your body rather than flat on the belly.

Surface drag is the resistance caused by the frictional force of a moving body in water. You can reduce surface drag not through technique but through preparation and equipment. Properly fitting swimsuits and swimming caps help achieve this result. For competition, shaving body hair and wearing special high-tech, low-drag swimsuits are common practices.

Use your senses to give you feedback about places on your body where you are fighting the water. Listen for splashing or kerplunking sounds and try to eliminate them. Try to make smooth, flowing movements, instead of bulldozing movements, with every part of your body. Look for large or numerous bubbles in the water around you. They are a sure sign that you are causing turbulence.

Figure 4.1The largest source of resistance in swimming is form drag (a). Reducing the front surface area that meets the oncoming water (b)can dramatically reduce form drag.

The technique work presented in this book will help you reduce or eliminate these drag indicators and thereby stop wasting energy.

Internal Resistance

Drag is not the only type of resistance with which a swimmer contends. There are three kinds of internal resistance as well: passive resistance, active resistance, and inertia. Passive resistance is caused by the soft connective tissues that surround joints and restrict a swimmer’s range of motion (ROM). Effective swimmers move through, or stretch to, the ends of their ranges of motion, where connective tissues begin to oppose and limit further motion.

Active resistance occurs when muscles work against each other. When first learning new skills, or when improving established skills, your neuromuscular system fires many more muscle fibers than are necessary to complete the desired actions. Many of these extra fibers work antagonistically against each other—a bit like a bunch of guys trying to push one car in several different directions. In addition, some people are, by nature or disposition, tenser than others. The person who is always wound up like a tight spring, bouncing and vibrating with just-waiting-to-be-unleashed energy, will have lots of muscle fibers working against others.

Inertia is the tendency for a body at rest on the couch to remain at rest on the couch—instead of grabbing the swim bag and heading to the pool. ’Nuff said.

The internal resistance of unwanted muscle tension or of poor range of motion will be reduced as you refine your stroke technique to avoid ineffective ranges of motion and improve your flexibility by regularly stretching into effective ranges. As you get better at performing skills in a relaxed and fluid manner, the neuromuscular system will fire fewer unnecessary muscle fibers, thus reducing the amount of energy lost to active muscular resistance. If you are like most athletes who undertake a planned program, the anticipation of improving will do wonders for overcoming couch inertia.

The drills and training approach in this book will help you to minimize resistance of all kinds in your swimming. The less resistance you work against, the more efficient you will be. You will have greater control over your workout, look more proficient as a swimmer, have more fun, and feel better about doing it all again.