Swimming requires both muscular strength and endurance. While endurance is the ability of the muscles to perform repeated submaximal contractions over time, strength is the amount of force that your muscles are able to produce. In swimming, muscular strength dictates how much force your muscles are able to apply to the water, which in turn propels your body forward.
Building Strength for the Novice Swimmer
For novice swimmers, swimming alone can effectively build muscular strength. According to former swimming professional Janet Evans, the water acts as resistance that the muscles have to overcome. Therefore, with consistent swimming, the muscles adapt and become stronger. Those who have been swimming consistently for months, however, will find that because of their muscle adaptations, the water resistance no longer provides enough of a stimulus to challenge their muscles and develop more strength. At that point, those who are looking to improve their swimming performance can incorporate strength-training exercises into their regimen to continue to build strength.
Main Muscles Involved in Swimming
Swimming recruits muscles throughout the entire body. However, there are specific muscles that are primarily responsible for producing the force that propels you through the water. The latissimus dorsi, which is the largest muscle in the back, pulls your arms down to your side and back behind you. The latissimus dorsi is a heavy contributor to all of the types of swimming strokes. Your shoulders and your pectorals, which are the major muscles in your chest, squeeze your arms together as you prepare for the next stroke. In the lower body, your gluteus maximus, hamstrings and quadriceps handle most of the force production at the hips and legs.
The Core Muscles Get Involved Too
Although your upper and lower limbs take on most of the force production, your swimming performance will be limited if you lack strength in your core muscles. Your lower back and abdominals keep your torso stabilized during all the strokes. When you're performing the free style and backstroke, your obliques are heavily involved in rotating your torso. The hip flexors, at the front of your upper legs, contribute to the kick.
Additional Strength Work
To develop greater muscular strength with the intention of improving your swimming performance, schedule two weight-training workouts per week. Perform each exercise for two to three sets of six to 10 reps. For your latissimus dorsi, incorporate lat pulldowns and seated rows. Strengthen your chest and shoulders with pushups and shoulder presses. For your hips, quadriceps and hamstrings, complete deadlifts and squats. Develop strength in your abdominals and obliques with bicycle crunches and front planks. Build up your lower back with back extensions and glute raises.