Sprinters require strong fast-twitch muscles.
If you're average, roughly half of your muscle fibers are categorized as slow twitch and half as fast twitch. But the ratio can vary a great deal. For example, fast-twitch fibers make up about three-quarters of a world-class sprint swimmer's muscles, according to USA Swimming. If you're a sprinter, it makes sense to perform exercises geared to your fast-twitch fibers, to help increase your speed.
Resist the Kickboard
Kickboard exercises are nothing new for swimmers. You typically hold the board so it's roughly parallel with the water's surface and start kicking. To build fast-twitch strength, particularly in your legs, hold the board perpendicular to the surface, with the flat side forward, and kick against the board's resistance. Swim eight 25-meter lengths of the pool while you hold the board in front of you, below the water's surface.
Train your fast-twitch fibers outside of the pool by lifting weights. You can select from a wide variety of exercises, but activities such as squats, lunges and deadlifts are good choices to build your calves, thighs and core. Perform lat pulldowns and bench presses to strengthen your chest, shoulders and upper arms. Determine your one-repetition maximum -- the heaviest weight you can lift one time -- for each exercise. Lift at least 60 percent of your one-rep max for each activity. Try to do one set at 75 percent of your one-rep max to recruit your largest fast-twitch fibers. Perform eight to 12 reps per set of each exercise or work up to that level.
Plyometric exercises involve explosive moments that help develop speed and power. Additionally, plyometrics provide another method for strengthening fast-twitch muscles. Perform forward bounds and hops or do depth jumps by standing on a raised platform, hopping down while landing flat on both feet, flexing your knees and then jumping vertically as high as possible. Perform the entire depth jump in one continuous motion. Do four to five sets of three reps per set.
Get Into Intervals
Interval training alternates bursts of high-intensity activity with a lower-intensity recovery period. Sprint swimmers, in particular, can perform a series very short intervals to further develop their fast-twitch fibers. Do a set of 20- to 25-second intervals by swimming your selected stroke as fast as possible for 20 meters. Glide forward or float for the remainder of the interval time to complete one repetition. Do 20 reps.
Warm Up First
No matter what type of training you perform, warm up with five to 10 minutes of aerobic exercise first. If you're in the pool, for example, swim slowly to warm up. Train your fast-twitch muscles two to four times per week, but don't work the same muscles two days in a row.