Not all swimming strokes are created equal. Some torch calories. Some build muscle. Some are gentle enough for anyone. Picking the right stroke for your goals makes the difference between a mediocre pool session and a genuinely effective workout.
Here’s an honest comparison of every major swimming stroke — what each one does for your body, how many calories it burns, and who should use it.
The Big Four: Competitive Strokes
Freestyle (Front Crawl)
Difficulty: Beginner-friendly
Calories burned per hour: 400-700 (depending on intensity and body weight)
Primary muscles worked: Latissimus dorsi, deltoids, triceps, core, hip flexors, quadriceps
Freestyle is the workhorse of lap swimming. It’s the fastest stroke, the most efficient, and the one you’ll see in almost every lane at every pool. The alternating arm pull and flutter kick create a full body workout with an emphasis on the back, shoulders, and core.
The reason freestyle dominates isn’t just speed. It’s sustainability. You can swim freestyle for 30, 45, or 60 minutes without the kind of fatigue that other strokes create. That sustained effort translates to serious calorie burn over time.
Best for: Overall fitness, endurance building, weight loss, anyone who wants to swim laps consistently
The catch: Breathing technique takes practice. Most beginners struggle with the head rotation and timing. But once you nail it, freestyle becomes second nature.
Backstroke
Difficulty: Beginner-friendly
Calories burned per hour: 350-600
Primary muscles worked: Latissimus dorsi, trapezius, deltoids, glutes, hamstrings, core
Backstroke is freestyle’s mirror image — you’re on your back with alternating arm pulls and a flutter kick. The calorie burn is slightly lower because the body position creates less resistance, but the muscle engagement is significant.
The big advantage for exercisers is the breathing. Your face never goes underwater. If breathing is the thing holding you back from swimming, backstroke solves that problem entirely.
Backstroke also hammers the posterior chain — upper back, glutes, and hamstrings — muscles that freestyle doesn’t target as aggressively. Swimming both strokes creates a more balanced physique.
Best for: Beginners, posture improvement, back strengthening, anyone who hates face-down breathing
The catch: You can’t see where you’re going. Wall collisions happen. Use the lane lines and overhead flags to navigate.
Breaststroke
Difficulty: Moderate
Calories burned per hour: 350-650
Primary muscles worked: Pectorals, inner thighs, hip adductors, quadriceps, hamstrings, glutes, calves
Breaststroke is the outlier. While freestyle and backstroke rely on flutter kicks and arm pulls, breaststroke uses a wide frog kick and a sweeping arm motion that targets completely different muscles. Your inner thighs, chest, and hips do most of the heavy lifting.
It’s slower than freestyle, but the muscle recruitment is unique. No other stroke works the inner thighs and hip adductors the way breaststroke does. For people looking for lower body emphasis, it’s unmatched.
Breaststroke also allows natural breathing since your head lifts above water on every stroke cycle. The pace is slower, which makes it feel less intense, but the calorie burn is still substantial because of the large muscle groups involved.
Best for: Lower body toning, chest development, knee-friendly swimming (if done correctly), social swimming
The catch: Breaststroke puts stress on the knees and inner knee ligaments if your kick technique is off. Learn proper frog kick form to avoid knee issues.
Butterfly
Difficulty: Advanced
Calories burned per hour: 600-900
Primary muscles worked: Pectorals, deltoids, trapezius, latissimus dorsi, abdominals, hip flexors, glutes, quads
Butterfly is the calorie incinerator. It burns more energy per minute than any other stroke. The simultaneous arm pull, dolphin kick, and undulating body motion create a workout that’s closer to high-intensity interval training than steady-state cardio.
The entire anterior chain fires during butterfly — chest, abs, hip flexors, quads. Combined with the back and shoulder work from the arm recovery, it’s arguably the most complete full-body exercise in the pool.
Best for: Maximum calorie burn, core strength, experienced swimmers who want intensity
The catch: Butterfly is exhausting. Even competitive swimmers rarely do more than a few hundred meters of butterfly in a single workout. Most people use it in short bursts mixed with other strokes. If you’re new to swimming, file butterfly under “later.”
Stroke Comparison Table
| Stroke | Calories/Hour | Difficulty | Best For | Primary Focus |
|---|---|---|---|---|
| Freestyle | 400-700 | Beginner | Endurance, weight loss | Back, shoulders, core |
| Backstroke | 350-600 | Beginner | Posture, breathing ease | Back, glutes, hamstrings |
| Breaststroke | 350-650 | Moderate | Lower body, chest | Inner thighs, chest, hips |
| Butterfly | 600-900 | Advanced | Max calorie burn, power | Chest, core, full body |
Calorie estimates based on a 155-pound person. Actual burn varies with weight, intensity, and fitness level.
Two More Strokes Worth Knowing
Sidestroke
Calories burned per hour: 250-450
Sidestroke is a survival and lifeguard stroke, not a competitive one. You swim on your side with a scissor kick and asymmetric arm pull. It’s slow but incredibly efficient and easy to sustain for long periods.
For exercise purposes, sidestroke is useful as an active recovery stroke or for people who find the competitive strokes too demanding. It also works the obliques and lateral muscles that other strokes miss.
Elementary Backstroke
Calories burned per hour: 250-400
Think of this as the relaxed version of backstroke. Arms sweep out to the sides and back (like making a snow angel), legs do a frog kick. Your face stays up and the pace is gentle.
Elementary backstroke is perfect for beginners who aren’t ready for full backstroke or freestyle. It builds water confidence and provides low-intensity exercise while you develop comfort in the pool.
Which Stroke Burns the Most Calories?
Butterfly wins on a per-minute basis. But here’s the reality: nobody swims butterfly for an hour straight. In practical terms, freestyle burns the most calories in a typical workout because you can sustain it longest.
A 45-minute freestyle session burns more total calories than 15 minutes of butterfly followed by 30 minutes of rest. Volume matters more than intensity when it comes to total caloric output in the pool.
For the absolute maximum burn, mix strokes. A workout combining freestyle with breaststroke and short butterfly sprints will torch more calories than any single stroke alone. Check out swimming workouts that burn more calories than running for specific routines designed to maximize calorie expenditure.
Choosing a Stroke for Your Goal
Weight loss: Freestyle for sustained effort, with butterfly intervals for intensity spikes. Track your output with how many laps you should swim based on your fitness level.
Muscle building: Alternate between butterfly (upper body), breaststroke (lower body), and freestyle (balanced). Variety recruits more total muscle.
Joint-friendly exercise: Backstroke and freestyle with a relaxed kick. Both are easy on the joints while still providing meaningful exercise. See our guide to pool exercises for weight loss for more low-impact options.
Cardiovascular fitness: Freestyle intervals. Swim 100 meters fast, rest, repeat. Progressively reduce rest intervals as fitness improves.
Posture and back pain: Backstroke. It strengthens the posterior chain and counteracts the forward-hunched posture that desk work creates.
How to Use Multiple Strokes in One Workout
The best swimming workouts mix strokes. Here’s a simple framework:
Warm-up (200m): Easy freestyle or backstroke
Main set: Alternate strokes every few hundred meters. Example: 4×100 freestyle, 4×50 breaststroke, 4×25 butterfly
Cool-down (200m): Easy backstroke or elementary backstroke
Mixing strokes prevents overuse injuries, works more muscle groups, and keeps sessions interesting. It’s the equivalent of doing a full-body gym circuit instead of just bench press for an hour.
FAQ
What is the easiest swimming stroke for beginners?
Backstroke and elementary backstroke are the easiest because your face stays above water and breathing is never an issue. Freestyle is the most useful stroke to learn but requires practice with breathing technique. Most swim instructors start adults with freestyle because of its versatility, but there’s no shame in starting with backstroke if breathing is a barrier.
Can you lose weight just by swimming one stroke?
Yes. Any sustained swimming burns calories regardless of stroke. Freestyle is the most practical for weight loss because you can maintain it for longer sessions, resulting in higher total calorie expenditure. A person swimming freestyle for 45 minutes three times per week will see meaningful results when combined with reasonable nutrition.
How long does it take to learn butterfly?
Most people need several months of consistent practice after they’re comfortable with freestyle. Butterfly requires coordination between the arm pull, dolphin kick, and breathing that takes time to develop. Start by practicing dolphin kick separately, then add the arm pull. Don’t rush it — bad butterfly technique is exhausting and can strain your lower back.
Should I swim the same stroke every workout?
Mixing strokes is better for overall fitness and injury prevention. Swimming only freestyle, for example, can lead to shoulder overuse issues. Adding backstroke and breaststroke works different muscles and gives your freestyle muscles recovery while still getting exercise. Even adding 200 meters of a different stroke to your routine makes a difference.
Which stroke is best for bad knees?
Freestyle and backstroke are the safest for knee issues because the flutter kick involves minimal knee bend and no lateral stress. Breaststroke is the riskiest for knees due to the frog kick’s rotational force on the knee joint. If you have knee problems, stick to flutter-kick-based strokes and avoid aggressive breaststroke kicking.