Swimming is often thought of as a key total body exercise, loaded with cardiovascular benefits and the ability to improve overall fitness. Yet, when discussing how to build muscle mass, there’s one debate that seems to be unanswered: is swimming truly effective for building muscle? Let’s dive into the topic to reveal the truth between swimming and muscle development.

Before exploring the impact swimming has on muscle growth, it is imperative to understand how muscles grow. Muscles are made up of muscle fibers, which are responsible for increased muscle size. 

Muscle growth is known as hypertrophy, and occurs when muscles obtain microscopic tears in the fibers in response to being put under stress. During recovery, muscle damage is repaired, and the muscle fibers adapt and strengthen to the new form of training.

Even though swimming primarily focuses on cardiovascular fitness, the ability to build muscle mass can be very different from traditional strength training. The natural resistance of water creates a unique challenge, and with consistency, visible, lean muscle hypertrophy can be accomplished. 

In swimming, water provides a natural resistance that provides a challenge for muscles throughout the entire range of motion of the stroke. 

Unlike exercises that are land-based where gravity, a machine, a cable, or bodyweight plays the main form of resistance, water creates challenges in every path, engaging muscles throughout each phase of the push and pull of the stroke.

Freestyle: The freestyle stroke involves a continuous motion of the arms and legs. The arms pull while the legs execute an up-and-down kick known as the flutter kick. This stroke engages the arms, shoulders, chest, back, core, and lower body muscles, requiring coordination of movement across the whole body.

Backstroke: A similar stroke to freestyle, backstroke engages the whole body in a synchronized manner. The alternating arm movements paired with the flutter kick and the core stability to stay afloat target the shoulders, neck muscles upper back, chest, abdominals, and legs, providing a full body workout.

Breaststroke: A unique stroke that involves a frog-like kick and a pull and push movement of shoulder muscles and the arms, breaststroke utilizes the chest, shoulders, arms, back, core, hips, and thighs. This stroke places a large emphasis on the chest, core muscles, hip flexors, and inner thighs, making it a powerful leg-driven movement.

Butterfly: Known for its forceful and demanding nature, the butterfly stroke requires a coordinated movement of the arms, resembling the motion of wings, combined with a dolphin kick. This stroke uses the muscles in the arms, shoulders, chest, back, core, and legs, demanding significant strength and endurance from the entire body. 

Due to the endurance-based nature of the sport, swimmers often exhibit a more streamlined physique, with well-defined muscles rather than larger, more bulkier ones seen in bodybuilders. Emphasizing muscle endurance promotes lean muscle development in multiple muscle groups rather than significant muscle mass development. Because of the sheer number of calories burned during swimming, the sport does not truly allow for muscles to grow exponentially. More lean mass is produced in muscle areas that are most involved. You often see the “swimmer's body”, with large, broad shoulders and a lean core.

Shoulders and arms: Focusing on building muscle size in the shoulders and arms, strokes such as freestyle, butterfly, and backstroke will provide the most benefit. These swimming strokes engage the deltoid and shoulder muscles, biceps (front of arms), and triceps (back of arms) through the repetitive motion of pulling through the water, creating resistance. The resistance effectively works these muscle groups.

Chest and Back: To build muscle in the chest and back areas, breaststroke and butterfly are the optimal strokes for these regions. Muscles such as latissimus dorsi (mid back), pectoral muscles (chest), and rhomboids (back of arm and shoulder muscles) are worked throughout the movement. The strokes involve powerful movements of the chest and back to create a forward drive and push through the water. Breaststroke, in particular, demands a forceful contraction of the chest and back muscles during the arm pull phase.

Core strength is necessary to maintain a streamlined body position while swimming. Flutter kicks and especially dolphin kicks in the various strokes engage the abdominal muscles (front of the stomach), building core strength. The side-to-side movements in strokes such as freestyle and backstroke activate the obliques (outer abdominal muscles), contributing to torso stability and strength. 

Quadriceps and Hamstrings: Working the quadriceps (front of legs) and hamstrings (back of legs) can be accomplished by working on the kicking portion of the stroke. The flutter kick used in backstroke and freestyle engages these muscles to push forward while swimming. In breaststroke, further emphasis is placed on the adductor muscle (innermost part of the leg) and the gluteal muscles during the powerful kicking motion. 

Calves: The continuous kicking motion of all the types of kicks used in swimming engages the calf muscles, therefore contributing to the overall strength of foot muscles.

While swimming offers a unique set of benefits for both muscle tone and muscle-building potential, comparing it to traditional resistance training can provide valuable insights into its effectiveness.

Volume in Swimming: Compared to strength training, swimming often requires longer durations of exercise, with swimming sessions lasting anywhere from thirty minutes to an hour or more. The effort required during swim sessions improves muscular endurance and cardiovascular health. The fatiguing of the muscle groups may take longer than in formal resistance training but does overall contribute to muscle growth.

Intensity in Resistance Training: Traditional resistance training, like the programs found in Peak Strength, often involves more intense, shorter sessions with a focused target on a specific muscle group or various muscle groups. The excess load and resistance on targeted muscles may lead to quicker muscle fatigue and failure, which in turn will build muscle faster.

Swimming: The various strokes and movements in swimming ensure a more balanced engagement of muscles. Each stroke emphasizes different body parts, providing a full-body, comprehensive workout. The variety in swimming allows for a different workout every session, stimulating the unity of muscles that may not work together in resistance training. 

Resistance Training: The variety of exercises possible in resistance training allows for specific muscle groups to be targeted and isolated, unlike swimming where full-body movements are implemented.

Swimming: The absence of gravity and excessive load on the joints during swimming provide a low-impact nature. The resistance of water on the joints is much gentler, making the exercise more suitable for individuals with joint concerns and those prone to and recovering from injury. 

Resistance Training: Certain forms of training that involve heavy weights can lead to significant stress on joints. Those with joint issues may find swimming to be a more accessible option. 

Individuals considering swimming to build muscle should take a strategic approach to maximizing its benefits. 

Similarly to strength training, to witness noticeable muscle growth through swimming, consistency, and progressive overload are crucial to success. Establish a regular schedule, whether it is a few times a week or more to ensure ongoing progress. Start with manageable distances and gradually increase the intensity and duration of your swims. This approach allows the body to adapt to training, build muscle, and reduce the risk of overuse injuries.

The numerous strokes, drills, and equipment available to swimming ensure a balanced development of muscle groups in your swimming routine. Freestyle, backstroke, breaststroke, and butterfly all offer their own set of unique benefits. 

Mix up what strokes you are practicing each session, or incorporate all strokes into your workout. Add in interval training, or high-intensity swimming, such as short sprint sets to challenge your speed and muscular power. Balance the high intensity with periods of lower-intensity, longer swims to increase muscular endurance and cardiovascular fitness. Add in equipment such as kickboards to focus on lower leg muscles or paddles and pull buoys to place extra load on the upper body muscles to increase muscle tension and endurance.

Supplement your swimming routine with strength training exercises to ensure total body muscular growth. Use strength training with weightlifting or resistance exercises to target specific muscles and improve development. Include stretching and flexibility to complement the dynamic movements of swimming. This can help to curb muscle imbalances and improve overall mobility.

Swimming is one of the best exercises for its cardiovascular benefits. It improves lung capacity, elevates heart rate, and increases cardiovascular endurance. The benefits of swimming on cardiovascular health prove it to be worthy as an addition to any fitness regimen to increase performance.

In the search for an effective and enjoyable regimen for building muscle mass, swimming is a great contender for muscular hypertrophy. The combination of low-impact water resistance, full-body engagement, and targeting of different muscles makes swimming a unique and compelling option for individuals of all fitness levels. 

Although, if you want to maximize your strength gains specifically for swimming, use Peak Strength to get a personalized strength program for swimming. 

Whether you are a seasoned swimmer or a newcomer to the swimming pool, the potential for muscle growth is vast and varied. The combination of water resistance, full-body engagement, and low-impact nature makes swimming a unique and compelling choice for individuals of all fitness levels.