Swimming

  • Author:
    Richard Weil, MEd, CDE

  • Editor: William C. Shiel Jr., MD, FACP, FACR
    William C. Shiel Jr., MD, FACP, FACR

    William C. Shiel Jr., MD, FACP, FACR

    Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.

View 7 Most Effective Exercises Slideshow Pictures

Introduction to swimming

Swimming is an activity that burns lots of calories, is easy on the joints, supports your weight, builds muscular strength and endurance. It also improves cardiovascular fitness, cools you off and refreshes you in summer, and is one that you can do safely into old age. In this article, I'll review the history of swimming, the benefits, the strokes, how to get started, what to wear, the equipment you need, where to swim, and more.

What is the history of swimming?

Human beings have been swimming for millennia. According to Wikipedia, Stone Age cave drawings depict individuals swimming and there are written references in the Bible and the Greek poems "The Iliad" and "The Odyssey" dating back 1,500 to 2,000 years. There are even Egyptian clay seals from 4000 BC showing four swimmers doing a version of the crawl, and the most famous swimming drawings were apparently found in the Kebir desert and were estimated to be from around 4000 BC.

According to the Encyclopedia of Traditional British Rural Sports, literature specifically related to swimming grew in the middle ages. It is believed that the first book devoted to swimming was Colymbetes by Nicolas Wynman written in 1538, and a more widely recognized text, De Arte Nantandi, was published in Latin by Everard Digby in 1587. The encyclopedia also reports that swimming was required of knights and that Romans built bathhouses and pools in the cities they conquered to serve as social clubs and places to exercise.

Organized swimming began in the 1800s and 1900s with the creation of swimming associations (for example, the Amateur Swimming Association in 1886) and clubs that competed against each other. There are reports from that era of swimming clubs in England, France, Germany, and the United States. High-profile events also contributed to swimming's visibility. For instance, Matthew Webb swam the English Channel in 1875.

Competitive swimming continued to grow in popularity during the 1800s and was included in the first modern Olympic Games in Athens in 1896. In 1904, the Olympics in St. Louis included the 50-, 100-, 220-, 440-, 880-yard and one-mile freestyle, the 100-yard backstroke and 440-yard breaststroke, and a 4x50-yard freestyle relay.

By the 20th century, swimming had become mainstream. Indoor pools were beginning to appear, most towns with populations over 20,000 had public outdoor pools, and swimming clubs became increasingly popular for recreation. Women participated for the first time in swimming in the Olympic Games in Stockholm in 1912, and Johnny Weissmuller (considered by many authorities to be the greatest swimmer of all time and who later went on to Tarzan fame in movies) became the first person to swim 100 meters in less than one minute.

Today swimming is the second most popular exercise activity in the United States, with approximately 360 million annual visits to recreational water venues. Swim clubs, recreation centers, Y's, and many other facilities feature swimming pools. Many high schools and colleges have competitive swim teams, and of course, swimming is one of the most popular Olympic sports. Millions of Americans are swimming each year. Are you one of them? If not, the following information may help get you started.

Quick GuidePictures of the 7 Most Effective Exercises to Do at the Gym or Home (and Tips to Improve Form)

Pictures of the 7 Most Effective Exercises to Do at the Gym or Home (and Tips to Improve Form)
Get helpful swimming safety tips.

Make Swimming Pools Safer

Medically Reviewed by Melissa Conrad Stöppler, MD

Nine people drown per day in the U.S. That's the average. It does not even include drownings from boat accidents. According to the CDC(Centers for Disease Control and Prevention), drowning rates have declined over the years, but drowning is still the second leading cause of injury-related deaths of children.

While most drownings of infants under a year of age occur in bathtubs, buckets, or toilets, most drownings of children 1-4 years of age occur in residential swimming pools. The facts surrounding the drownings of young children in residential pools can send a chill down any parent's spine:

  • Most children who drowned in pools were last seen in the home.
  • Most young children who drowned in pools had been out of sight for less than five minutes.
  • The majority of children who drowned in pools were in the care of one or both parents at the time.

If you have a pool at home, be sure it is as safe as possible. Never, ever, leave a child unsupervised in or near a pool.

The American Red Cross recommends the following steps to maximize the safety of home swimming pools.

What are the swimming strokes?

Breaststroke, backstroke, butterfly, and crawl (freestyle) are the most popular swim strokes. The breaststroke and butterfly are more difficult to learn than the backstroke and crawl.

Breaststroke

The breaststroke involves exquisite timing, and in fact, you can be disqualified from competition if you miss even one stroke. The stroke involves form that causes your body to bob up and down as you glide forward through the water. This is a difficult stroke and not one to choose if you're just learning how to swim. The basics are that your arms pull, you breathe, you kick (arms alternate with the kick), and you glide. Here are details.

The leg kick:

  • Bring the knees to chest.
  • Thrust the legs backward and straight.
  • Snap the legs together to push the water and propel you forward (frog kick).

The arm stroke:

  • Start with the arms overhead.
  • Pull on the water, and bring arms toward the chest.
  • Keep the hands cupped.
  • Return arms to starting position.

The breathing:

  • Breathe every time you stroke with your arms.

Butterfly

Like the breaststroke, this is a difficult stroke and not recommended for beginners because it requires perfect timing and a good deal of strength. During the stroke, the legs move together in a dolphin kick (imagine a mermaid), the arms move together to push the water downward and backward, and the torso undulates like an earthworm as the body moves forward through the water.

The leg kick:

  • Bend the knees slightly, and keep them together.
  • Make a downward thrust by straightening the knees and whipping the feet downward.
  • There should be two kicks for every arm stroke.

The arm stroke:

  • Move the arms together, and pull through the water with the hands cupped.
  • Face the palms outward, and press down and outward.
  • Swing the arms forward above the water in a sweeping motion to complete the stroke.

The breathing:

  • Breathe at the end of the arm stroke.

Backstroke

The backstroke is easier than the butterfly or breaststroke and similar to the crawl in that you use an alternate windmill arm stroke and flutter kick. Two keys to a proper backstroke are that your arms move with equal strength, otherwise you will swim off to one side, and that your body rolls from side to side so that your arms catch enough water to propel you forward.

The leg kick:

  • Is a flutter kick where the legs kick in an alternating order.
  • Bend the knees slightly.
  • Relax the feet and ankles (they should be almost floppy).
  • Emphasize the up-kick for propulsion.

The arm stroke:

  • Move the arms in an alternating, windmill pattern as they rotate and pass your face.
  • Cup the hands, and the thumb leaves the water first.
  • Move the hands in an "S" pattern when they are pushing the water.

The breathing:

  • Keep your head back and eyes toward the ceiling.
  • You can find your own breathing pattern with the backstroke because the breathing is less coordinated with the arms and kick than other strokes since your head should always be out of the water.

Crawl (freestyle)

This is the most popular stroke and the easiest for beginners to learn. It is a simple flutter kick and windmill arm motion, like the backstroke, only on your belly. The most difficult part is coordinating the breathing since your face is in the water most of the time.

The leg kick:

  • It's a flutter kick where the legs kick in an alternating order.
  • Bend the knees slightly.
  • Relax the feet and ankles (the should be almost floppy).
  • Emphasize the down-kick for propulsion.

The arm stroke:

  • Move the arms in an alternating windmill motion.
  • Pull each arm through the water with equal strength and arm reach to ensure that you swim straight.
  • Pull arms underwater in an "S" pattern.
  • Cup the hands but keep the wrist and hand relaxed during recovery.

The breathing:

  • Raise one arm to begin the stroke. As the shoulder rises, turn the head to catch a breath.
  • Turn the head only enough to leave the water to breathe. Do not lift the head because it will slow you down.
  • Take as many breaths as necessary and then exhale through the nose and mouth when the head returns to the water.
  • Repeat the head turn to the other side in coordination with the beginning of the opposite arm stroke.

The freestyle flip turn (when swimming the crawl)

There are a couple of options for turning around when you reach the wall during lap swimming. You can simply touch the wall and turn around and start swimming again or you can do a flip turn. The flip turn is essentially a somersault in the water where you flip and turn and use your legs to power-kick off the wall. The flip turn, when completed properly, is fast, efficient, and time-saving. If you've ever watched Olympic swimming, you see the swimmers gracefully execute their flip turns. Here are the basics.

  • Start the somersault before reaching the wall by tucking the chin and pulling the knees into a tuck position.
  • Blow out air to avoid inhaling water.
  • Straighten out the body-tuck halfway through the flip and extend the legs toward the wall.
  • You will be on your back at this point.
  • Push off the wall.
  • Roll over onto the belly and glide toward the surface of the water.
  • Hold the glide until you break the surface of the water, and then start stroking immediately.

The flip turn takes practice, but with consistent work, you can master it. It's worth trying if you swim laps for exercise.

What equipment do I need for swimming?

Swimsuit

You'll need a swimsuit unless you plan on skinny-dipping! Like many other things, technology has entered the swimsuit arena as well. Fabrics are designed for minimal resistance through the water, they tend to last a long time, and they resist fading even when used repeatedly in chlorinated pools. Of course, not all of us would be comfortable in the skimpy racing suits that you see Olympians wear, but the good news is that you can find more modest suits at sporting goods and department stores as well as through a number of online vendors (see the resources section). Comfort is the most important quality in selecting a swimsuit. You're less likely to swim if you're uncomfortable in your suit.

Goggles

Goggles protect your eyes from chlorine (and anything else that may be in the water), and they help you keep your eyes open while you swim so that you can see where you're going. You can even get prescription swim goggles if you wear glasses (check with your optician for availability). To find the right pair of goggles, do the following:

  • Put the goggles over your eyes without slinging the strap over your head.
  • Press the goggles into your eye sockets and let go.
  • The goggles should stay in place.
  • Experiment until you find the pair that fits your eyes best.

Bathing caps

Bathing caps can serve several purposes. Some pool managers will require individuals with long hair to wear caps to keep hair from getting into the pool, and some people just like to protect their hair from the chlorine in the water. You may also decide to wear a bathing cap to cut down on resistance in the water. This really works, and so if you're looking to increase your time a bit, a bathing cap might help. Many caps are made of latex, although you can find silicone, neoprene (keeps you warm), and Lycra as well. Choose the one that fits your head and is most comfortable.

Flotation devices and other equipment

There are a number of flotation devices and other equipment available to help you learn how to swim, improve your swimming times if you start to get competitive, and add resistance to your water workouts to build muscular strength and tone. Flotation devices help keep you afloat so that you can slow down and work on your swim stroke without sinking or causing too much fatigue, and they help with confidence for individuals who don't know how to swim. Read on to learn more about floatation devices.

Kickboards

Kickboards are devices made of foam or other materials that float, and they come in a variety of shapes and sizes. The main purpose is for you to hold on and stay afloat while your legs do all the work. It's good exercise for coordinating your kicking, and it gives your arms a rest. One technique that I suggest to swimmers who want to keep swimming continuously without a break is to leave a kickboard at the end of the pool, and when they get tired, grab the kickboard and do a lap or two with it until they get their arm strength back, and then drop the kickboard off at the end of the pool and swim again until they need the kickboard again. Many pools have kickboards available to try out.

Pull buoys

Like kickboards, pull buoys are flotation devices that come in a variety of shapes and sizes, but unlike a kickboard, which gives the upper body a rest, pull buoys are placed between the legs to keep the legs afloat without kicking so that you can work your upper body. Pull buoys are excellent training devices for building upper-body strength, endurance, and cardiorespiratory fitness. They can also help you work on your form because you can swim slowly and deliberately without sinking.

Fins

Fins fit on your feet and add propulsion to your kicks (think of a duck's webfoot). They are great training for your legs and will help you swim faster. They come in long fins for beginners who want to work on their stroke and build up leg strength and ankle flexibility and short fins to help you go faster without overworking your legs. Fins should fit snugly but not so tight that they cut into your foot or cut off circulation. Wear socks with your fins if that feels more comfortable.

Hand paddles

Hand paddles attach to your hands and add propulsion to your arm stroke because they move more water. They can be a lot of work for the arms and shoulders because of the resistance in the water, and for this reason, they are used in water aerobic classes to mimic the resistance exercises that you do on land with dumbbells (for example, biceps curls). Hand paddles make a water workout difficult, and so you should warm up in the water without them first, and then build up slowly like you would with any resistance exercise workout so that you don't overwork your arms and shoulder joints.

Gloves

Gloves, like hand paddles, also add resistance for your arms, although they are smaller than paddles and so the resistance is lighter. These might be a better choice than paddles if you're just starting out with resistance exercises in the water.

Water dumbbells

Some manufacturers produce dumbbells made of foam for use in the water. They add resistance like paddles or gloves, but you can release them quickly after a set and then grab them again when you're ready. Water creates lots of resistance, and so water dumbbells will make you stronger if you use them consistently. They're fun!

Noodle

A noodle is a flexible, tube-shaped flotation device that you can wrap under your arms or around your waist to keep you buoyant so that you can keep moving in the water (kids love to play with them). The advantage of being able to keep moving is that you can work on your stroke without fatigue and increase your strength and endurance.

Aqua jogger

Aqua jogger is a flotation device that you wear like a belt. Like a noodle, it permits you to keep on moving without fatigue, so that you can work on your stroke as well as your strength and aerobic fitness, but it's more heavy-duty than a noodle and will accommodate heavier people and create more resistance. Aqua joggers also allow you to participate in water aerobic classes and water running without having to know how to swim or break frequently.

Water treadmill

Did you read that right? Yep, water treadmill. There are two types. One is a device that you install in your pool that works with a propeller to create a current of water that you swim in place against (okay, it's not really a treadmill, but you do swim in place). This type is a great training aid and is also used for rehabilitation, but it is very expensive, depending on the model and whether you have it installed when your pool is being built or in an existing pool. The other type is a treadmill that is designed for use in water. You walk on it just like any land-based treadmill, only there is less strain on your joints because of the water. This type of treadmill is frequently used in rehabilitation. See the resources section or search online for "water treadmill" to learn more.

There is one other option for swimming in place, and it's inexpensive. Swim stretch cords attach to the side of a pool and to your body so you can swim without going anywhere, or they come with a drag belt (sort of like a mini-parachute) that catches water as you swim and drag it behind you. Both are fine options for getting a great workout.

Quick GuidePictures of the 7 Most Effective Exercises to Do at the Gym or Home (and Tips to Improve Form)

Pictures of the 7 Most Effective Exercises to Do at the Gym or Home (and Tips to Improve Form)

What are the benefits of swimming?

There are plenty of reasons to swim! Here's a list that should get you motivated.

Low impact

There's no ground impact when you swim, and so you protect the joints from stress and strain. In fact, the Arthritis Foundation strongly recommends swimming and water activities for this reason, so much so that they sponsor water classes all over the country (check http://www.arthritis.org for information). Water aerobics classes are also desirable for this reason, because even if you do jump and hit the bottom of the pool, you do so with less force because you're buoyant in the water. Not only that, but if you wear or hold a flotation device during a water aerobics class, the impact is even less.

Can be continued for a lifetime

Because there's no impact with swimming, it can be continued for a lifetime. If you check the United States Masters Swimming (http://www.usms.org/) Web site for age categories of their swim competitions, you will find a 100- to 104-year-old age group! And the master of fitness, Jack La Lanne, who died in 2011, reportedly still swam one hour every day at age 93!

Builds cardiorespiratory fitness

Swimming improves endurance. In one study of sedentary middle-aged men and women who did swim training for 12 weeks, maximal oxygen consumption improved 10% and stroke volume (the amount of blood pumped with each beat which indicates heart strength) improved as much as 18%.

Builds muscle mass

In a study of men who completed an eight-week swimming program, there was a 23.8% increase in the triceps muscle (the back of the arm). My take on muscle mass and swimming is that if you have been doing no resistance exercise at all and you start to swim, you will certainly get more toned and you may even gain mass like the men in this study. But even without the gain in mass, it's well worth the strength and tone that you will almost certainly gain.

An alternative when injured

When athletes are injured, particularly in the lower extremities, they are frequently told to swim to maintain their fitness level. Swimming helps them stay in shape, and it's even part of the rehabilitation. That's because the resistance of the water makes the muscles work hard without the strain or impact that is experienced on land.

It's a break from the summer heat

There's nothing like it during the hot days of summer, whether it's at the beach or in the pool. It's relaxing, the movements are smooth and rhythmic, and it's a great workout.

It's a family affair

Swimming and other water activities are something the entire family can share. With rising levels of obesity in children as well as adults in the United States, family physical activities and good role-modeling may be one way to stem the epidemic of inactivity and obesity facing our nation.

Burns calories

Swimming burns lots of calories, anywhere from 500-650 per hour depending on how efficiently you swim (you burn more flopping around than swimming cleanly!) and how buoyant you are (the more body fat you have, the more you float and the fewer calories it takes to swim). Very early and original research on swimming and calorie expenditure showed that swimming, regardless of the stroke, burned about 89% of the calories burned during running and 97% of the calories burned during cycling for the same time period. Stated another way, swimming burns about 11% fewer calories than running but only 3% fewer calories than biking. One important caveat about this data is that calorie expenditure is dependent on the intensity of exercise, and so it's entirely possible to burn more calories swimming than running in the same period of time as long as you swim hard enough, and particularly so if compared to running at light intensity.

How do I get started with swimming?

Take a lesson if you don't know how to swim! It's never too late to learn. Your local recreation center, Y, fitness center, or senior center might have a pool, and if they do, chances are they offer swim lessons (plus, if it's indoors, you can swim all year long!). You may have the choice of group or private lessons. Opt for a private lesson if you have a strong fear of the water and feel you need special attention, otherwise a group lesson will work just fine.

A qualified swim instructor will have some type of certification (for example, the American Red Cross-certified lifeguard and swim instructor) and will be willing to speak with you before you get started to explain how things work. Adults generally need one hour for beginning sessions, but that may vary based on your health and fitness level (children younger than 6 years of age need 15-30 minutes and 6- to 12-year-olds need 30-45 minutes). The instructor should use kickboards, float belts, or other flotation devices to assist you if necessary, and they should be sensitive to any fear of the water you might have. When you first start, you should expect to learn breathing and stroke techniques separately, and then the instructor will integrate your lessons as you get more comfortable and skilled. You might start in the shallow end where you can stand and work on breathing techniques, by the side of the pool and hold on while you kick, or perhaps hold on to a kickboard and kick across the pool to work on kicking strokes. Depending on your skill and comfort in the water, you might move quickly to a float belt or other flotation device and start working on your arm strokes and coordinating them with kicking. Your instructor will know how quickly to progress.

What if I already know how to swim?

That's easy! Join a local pool and get started. Swimming is a tough activity and even if you've been working out for years running and biking and using the elliptical, you may be surprised by how much endurance swimming requires. If that's the case, then it's probably due to poor stroke and breathing technique (swallowing water will slow you down every time!), which is to be expected if it has been years since you last swam. But it will come back with practice.

One way to get started is to pace yourself with intervals. By that I mean swim for five to 10 minutes, or as long as you can manage without stopping, take a breather, then get right back to it and swim again until you need another break, and then go again. Or you could do as I suggested earlier with kickboards by leaving it on the pool deck and swimming until you're tired, but instead of stopping, pick up the board and continue to kick. Or you could use a float belt or similar device to help you float so that you can continue to swim or slow down to work on technique. Be creative!

Whatever method you choose to get back into it, swim consistently, and in just a matter of weeks, your fitness for swimming will improve.

Quick GuidePictures of the 7 Most Effective Exercises to Do at the Gym or Home (and Tips to Improve Form)

Pictures of the 7 Most Effective Exercises to Do at the Gym or Home (and Tips to Improve Form)

Are there swimming organizations that I can join?

Check your local pool to see if they have a club that you can join. You can also check out United States Masters Swimming (http://www.usms.org/), a national, nonprofit organization with 500 clubs in 53 regions throughout the United States that organizes workouts, competitions, clinics, and workshops for adults ages 18 and over, with members as old as 100!

Can my young child start swimming?

There are many clubs and pools that offer swim lessons for infants and children, but parents should be cautious. The American Academy of Pediatrics (AAP), a medical organization of 55,000 primary care pediatricians and pediatric medical specialists that sets guidelines for pediatric health in the United States, states that children are not developmentally ready for formal swimming lessons until after their fourth birthday. According to the AAP and its policy statement "Swimming Programs for Infants and Toddlers," drowning is a leading cause of unintentional injury and death in the pediatric age group and that drowning rates are highest among toddlers ages 1 to 2 years of age. They note that while an estimated 5-10 million infants and preschool children participate in aquatic programs, these should not be promoted as a way to decrease the risk of drowning. They emphasize that parents should not feel secure that their child is safe in water or safe from drowning after participating in an aquatic program. Ultimately, the conclusion is that, "Whenever infants and toddlers are in or around water, an adult should be within an arm's length, providing 'touch supervision.'"

What about triathlons?

Triathlons combine swimming, running, and biking into one big event. Distances for each event vary with six-mile runs up to full marathons, 25- to 100-mile bike rides, and half-mile lake, river, or pool swims to two-mile ocean swims. Triathlons are growing in popularity across the United States and combine the athletic challenges of strength, endurance, determination, and discipline. Check out the USA Triathlon Web site at http://www.usatriathlon.org/ to learn more about triathlons.

What about swimming with disabilities?

Water is a great equalizer. It supports body weight, and with proper flotation devices, most anyone can exercise in the water no matter what the physical disability. Check locally at Y's, recreation centers, and other pools for opportunities in your area, or click on the USA Swimming Web site (http://www.usaswimming.org/) to learn more (click on the "swimmer" tab and then "disability"). In addition to recreational swimming, the United States Paralympics Swim Team offers athletes with disabilities (amputees, blind/visually impaired, spinal-cord injured/wheelchair, cerebral palsy/brain injury/stroke) the opportunity to compete internationally in swimming. Swimming is an activity for virtually anyone who has the will and desire to do so.

Summary

There you have it. Swimming is an activity that builds strength, endurance, and muscle tone. It's an activity that you can do all year long, inside or outside, burning lots of calories. You can share it with your family, it's low-impact (just in case your bones are creaky), and you can do it until you're 100! It's not too late to start if you never learned how (learning new stuff is cool even when you're adult!), and for those of you who can swim and would like to compete, that's available as well. All in all, swimming is a winner, and if you have the inclination, I suggest that you go for it!

What resources are available to people interested in swimming?

http://www.usms.org/

http://www.ymca.net/ (Click on aquatics to learn more about infant-parent classes, preschool classes, classes for people with disabilities, classes for teens, and competitive swimming for people 18 and over.)

http://www.arthritis.org/ (Check for water classes in your area.)

http://www.usaswimming.org/ (Click on the "swimmer" tab and then "disability.")

http://www.usswimschools.org/

http://www.swimoutlet.com/AquaJogger

http://www.swimmingworldmagazine.com/

http://www.usatriathlon.org/

http://www.junonia.com/home.htm (large-size swimsuits for women)

http://www.wholesomewear.com/slimmer-c.html (large-size swimsuits for women)

http://www.bigmen.com/ (large-size swimsuits for men)

http://www.big-tall.com/ (large-size swimsuits for men)

http://www.bigandtallguys.com (large-size swimsuits for men)

http://www.swimoutlet.com/ (swim gear)

http://aquajogger.com/default.htm (swim gear)

http://www.shapeupshop.com/aqua/hand_buoys.htm (water dumbbells)

http://www.power-systems.com/ (water dumbbells)

http://www.activeforever.com/ (water treadmill)

http://www.endlesspools.com/index.html (water treadmill—propeller method)

http://www.americanswimmingassociation.com/

Medically reviewed by Avrom Simon, MD; Board Certified Preventative Medicine with Subspecialty in Occupational Medicine

REFERENCES:
http://www.olympic.org/uk/athletes/profiles/bio_uk.asp?PAR_I_ID=50419 July 23, 2007
http://www.aap.org/advocacy/archives/aprswim.htm July 27, 2007.
http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5222a1.htm
http://www.jacklalanne.com/ July 26, 2007.
Encyclopedia of Traditional British Rural Sports, Routledge; first edition, August 9, 2005, pp 255-6.
Holmér, I. Oxygen uptake during swimming in man. J Appl Physiol. 1972 Oct;33(4):502-9.
Lavoie, J.M., et al. Skeletal muscle fibre size adaptation to an eight-week swimming programme. Eur J Appl Physiol Occup Physiol. 1980;44(2):161-5.
Martin, W.H., et al. Cardiovascular adaptations to intense swim training in sedentary middle-aged men and women. Circulation. 1987 Feb;75(2):323-30.
Pediatrics, Vol. 105 No. 4, April 2000, pp. 868-870.
U.S. Bureau of the Census. Statistical abstract of the United States: 1995. 115th ed. Washington, DC: U.S. Bureau of the Census, 1995.

Subscribe to MedicineNet's Weight Loss/Healthy Living Newsletter

By clicking Submit, I agree to the MedicineNet's Terms & Conditions & Privacy Policy and understand that I may opt out of MedicineNet's subscriptions at any time.

Reviewed on 5/20/2015
References
Medically reviewed by Avrom Simon, MD; Board Certified Preventative Medicine with Subspecialty in Occupational Medicine

REFERENCES:
http://www.olympic.org/uk/athletes/profiles/bio_uk.asp?PAR_I_ID=50419 July 23, 2007
http://www.aap.org/advocacy/archives/aprswim.htm July 27, 2007.
http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5222a1.htm
http://www.jacklalanne.com/ July 26, 2007.
Encyclopedia of Traditional British Rural Sports, Routledge; first edition, August 9, 2005, pp 255-6.
Holmér, I. Oxygen uptake during swimming in man. J Appl Physiol. 1972 Oct;33(4):502-9.
Lavoie, J.M., et al. Skeletal muscle fibre size adaptation to an eight-week swimming programme. Eur J Appl Physiol Occup Physiol. 1980;44(2):161-5.
Martin, W.H., et al. Cardiovascular adaptations to intense swim training in sedentary middle-aged men and women. Circulation. 1987 Feb;75(2):323-30.
Pediatrics, Vol. 105 No. 4, April 2000, pp. 868-870.
U.S. Bureau of the Census. Statistical abstract of the United States: 1995. 115th ed. Washington, DC: U.S. Bureau of the Census, 1995.

Health Solutions From Our Sponsors