Combining Slow Twitch & Fast Twitch Workouts

Woman stretching in forest

Muscle-building workouts can be helpful for sports as well as preparing for physically demanding jobs, but not all muscle-focused workouts are the same. Your muscles are comprised of two types of fibers -- slow twitch and fast twitch. As the names suggest, fast twitch muscles are effective for quick bursts of strength, but they have less ability to sustain power over time than slow twitch muscles, which are better for endurance activities. For the best of both worlds, you can combine slow twitch and fast twitch workouts for highly effective, multi-disciplinary training.

Visit your doctor for a physical evaluation prior to beginning your workout program. If your training in the past has concentrated on just one type of muscle fiber, you may have some physical limitations around which you will have to plan your training. Explain to your doctor your goals and your injury history so he can provide comprehensive recommendations for you.

Create a workout schedule based on your desired goals and availability. Decide whether you want to split your workouts based on muscle group, muscle fiber type, movement -- push or pull, for example -- or muscle location, such as upper body and lower body. If you prefer to improvise, you should at least determine which days you will exercise and which you will leave for rest.

Include endurance activities for your slow twitch muscle fibers. Choose an activity such as running, cycling and rowing for a duration of 30 to 45 minutes to improve slow twitch muscle fiber endurance. If you do not enjoy long cardio sessions, perform your slow twitch exercises at the beginning and end of your workout sessions for 15 minutes each.

Perform plyometric exercises such as clap push-ups, medicine ball slams, squat jumps and bounding for your fast twitch muscle fibers. Perform these exercises on padded materials to reduce your risk of injury. Alternate between lower and upper body exercises to battle fatigue.

Fill in the rest of your workouts with resistance exercises such as the bench press and pull-down for your upper body and squats for your lower body. Vary the number of sets and repetitions you perform to focus on slow and fast twitch fibers. Use heavier weights and fewer repetitions for fast twitch fiber training, and lighter weights with higher numbers of repetitions for your slow twitch fibers.

Assess your progress by analyzing your exercise performance. Track improvements in your slow twitch muscle fibers by comparing your longest cardio durations and best paces. Assess your fast twitch muscle fiber improvement by tracking how much weight you can lift for a set number of repetitions, such as six or eight, in a variety of exercises.

Alter your workout program based on your strengths and weaknesses. Prioritize cardio workouts if your slow twitch fibers are lagging behind. Set aside entire workouts for cardio rather than leaving cardio for warming up and cooling down around your weight workouts. Cut back on endurance activities and concentrate more on weight training if your fast twitch muscle fibers are not showing improvement.


Always exercise with supervision.

If you feel any muscle pain, stop working out immediately.

Progress at a comfortable pace -- trying to do too much too quickly can result in an injury.