There are four competitive swimming strokes used in races worldwide: freestyle (front crawl), backstroke, breaststroke, and butterfly. Beyond those, several utility and historical strokes bring the total to around nine or ten distinct techniques, each with a different body position, kick pattern, and purpose in the water.
Freestyle (Front Crawl)
Freestyle is the fastest and most common swimming stroke. You lie face down in the water, alternating your arms in an overhead windmill motion while performing a flutter kick with your legs. Breathing happens by rotating your head to one side during the arm recovery phase. Most swimmers breathe every two or three strokes.
The stroke engages a wide chain of muscles during each pull: the lats, chest, biceps, and triceps do the heavy lifting in the water, while the core and obliques stabilize your body rotation. During the recovery phase, the upper back and shoulder blade muscles take over. For a 150-pound person swimming at a moderate pace, freestyle burns roughly 594 calories per hour, climbing to about 716 calories at a vigorous intensity.
Freestyle has deep roots. Overarm swimming techniques date back to the ancient Assyrians and Greeks, at least 800 years before Christ, and were the natural style of South Sea Island peoples and North American Indigenous swimmers. The modern version took shape after the 1912 Stockholm Olympics, when Hawaiian swimmer Duke Kahanamoku used a six-beat flutter kick to win the 100m freestyle gold. The name “front crawl” itself came from Australian swimmer Dick Cavill in the late 1800s, who described his technique as crawling through the water.
Backstroke
Backstroke is essentially a flipped version of freestyle. You float face up, alternating your arms in a windmill motion behind your head while flutter kicking. Because your face stays above water the entire time, breathing is unrestricted, which makes it a comfortable stroke for people who struggle with the timing of breathing in other styles.
The muscle activation pattern during backstroke closely mirrors front crawl. The lats, chest, biceps, and triceps generate force during the underwater pull, while the trapezius and shoulder blade muscles control the recovery. The core works throughout to keep you from rolling too far side to side. Calorie burn at a light to moderate effort is about 476 per hour for a 150-pound person, rising to around 680 at higher intensities.
Breaststroke
Breaststroke is the slowest of the four competitive strokes but one of the most intuitive for beginners. You start in a streamlined position face down, then sweep both arms outward and around in a heart-shaped pull while simultaneously drawing your knees up and kicking outward in a “frog kick.” Your head lifts forward to breathe at the top of each arm pull, then tucks back into the glide.
The glide phase is what makes breaststroke distinct. After each kick, you hold a streamlined position and coast before starting the next stroke cycle. This makes it feel rhythmic and manageable at low speeds, though racing breaststroke at full effort is surprisingly demanding. A moderate effort burns roughly 379 calories per hour, but vigorous breaststroke jumps to about 737 calories, actually surpassing freestyle at the same intensity. The kick places significant load on the inner thighs and knees, which is worth knowing if you have knee issues.
Butterfly
Butterfly is the most physically demanding stroke. Both arms sweep forward over the water simultaneously in a wide arc, while your body undulates in a wave-like dolphin kick. You breathe by lifting your chin forward as your arms exit the water. The timing is precise: two dolphin kicks per arm cycle, one as the hands enter the water and one during the pull.
The calorie cost reflects how hard this stroke works. At a moderate pace, butterfly burns approximately 748 calories per hour for a 150-pound swimmer. Push to vigorous intensity and that climbs to nearly 988 calories, making it the highest calorie-burning stroke by a wide margin. Butterfly requires strong shoulders, a flexible spine, and solid core control, which is why most swimmers only sustain it for shorter distances.
Butterfly has an interesting origin. It started as a variant of breaststroke in the 1930s, when swimmers discovered that bringing both arms over the water was faster than sweeping them underwater. Officials eventually separated butterfly into its own event because it was dominating breaststroke competitions.
Sidestroke
The sidestroke is swum entirely on one side. Your lower arm extends forward and pulls toward your chest while your upper arm pushes down along your body, and your legs perform a scissors kick. The whole motion is smooth and energy-efficient, which is why lifeguards still use a modified version to tow people to safety during water rescues.
Though it was once a competitive stroke, sidestroke fell out of racing use decades ago. It remains valuable as a practical, low-fatigue way to cover distance in open water.
Elementary Backstroke
Elementary backstroke is one of the first strokes many people learn in swim lessons. You float on your back with arms at your sides, then simultaneously sweep your arms up along your torso to shoulder height while drawing your knees up into a frog kick. After the kick and arm push, you glide in a streamlined position before repeating.
The technique is simple by design. Because your face stays above water and the movements are symmetrical, it requires almost no coordination compared to front crawl or butterfly. It’s a useful stroke for building water confidence and for swimming at a relaxed pace without tiring out quickly.
Combat Sidestroke
The combat sidestroke is a modified sidestroke developed for military use, most notably by U.S. Navy SEALs. It blends elements of freestyle, breaststroke, and sidestroke into a technique optimized for covering long distances efficiently with minimal surface disturbance. The low profile in the water was originally designed for tactical situations, but it has become popular among fitness swimmers who want an energy-efficient alternative to freestyle.
Trudgen and Double Overarm
The Trudgen stroke is a historical technique that bridged the gap between breaststroke and modern freestyle. In 1873, Englishman John Trudgen demonstrated it at the Lambeth Baths in London, swinging both arms alternately over the water while using a horizontal breaststroke kick. He said he had learned it from South African swimmers during his time living abroad. The stroke made him the fastest sprinter of his era, though his high head position and jerky kick look nothing like today’s front crawl.
During the 1890s, swimmers modified the Trudgen by replacing the breaststroke kick with a scissors kick performed on alternating sides. This became known as the double overarm stroke. It was a stepping stone toward the flutter-kick crawl that eventually took over competitive swimming in the early 1900s. Neither stroke is used today, but they played a critical role in how modern freestyle developed.
Dog Paddle
Dog paddle is the simplest swimming motion: you stay mostly upright or at a slight angle, head above water, paddling your hands in small alternating circles beneath the surface while performing a basic flutter or bicycle kick. It’s not efficient and won’t win any races, but it keeps your head above water and requires zero instruction, which is why it’s often the first thing children and untrained swimmers do instinctively.
Dog paddle has a surprisingly long history. It was the standard stroke across parts of continental Europe through the 1500s and persisted among some populations even as breaststroke and overarm techniques became dominant in competitive settings.
How the Strokes Compare for Exercise
If your goal is fitness, the stroke you choose significantly affects your workout. Here’s how a 150-pound person’s hourly calorie burn breaks down at moderate to vigorous effort:
- Butterfly: 748 to 988 calories
- Breaststroke: 379 to 737 calories
- Freestyle: 594 to 716 calories
- Backstroke: 476 to 680 calories
Butterfly tops the list but is difficult to sustain for a full workout. For most people, alternating between freestyle and breaststroke gives the best combination of calorie burn, muscle variety, and endurance. Backstroke is a good active recovery option between harder sets, and it gives your shoulders a break from the overhead position used in the other three competitive strokes.