Many people make the mistake of only ever training one muscle fiber type. We are all born with different proportions of 3 muscle fiber types, which give us all different body shapes and abilities, notably important in athletics and whether your body is geared more towards endurance or power activities. For the exercise enthusiast and health conscious. Training the full spectrum of your muscle mass is important to developing your lean mass and warding off fat mass. Type 1 fibers are also referred to as slow twitch muscles. They have a high oxygen carrying capacity, which aids slow sustained contractions of moderate output, endurance. Training these fibers includes endurance activities such as steady state cardio, and resistance training programs above 20 repetitions at a lower weight and speed.
Type 2 fibers, also known as fast twitch, allow rapid contractions of high intensity for a short amount of time, power. Activities include explosive movements, such as strength and power lifting with repetitions below 6, anaerobic activities like sprinting, jumping, etc for intervals less than 60 seconds or so. These fibers have been categorized further into type 2a and type 2b, but we will not get into that in this blog.
Suffice to say we are all built to have a greater proportion of one fiber type than the other. Allowing us to be better at certain activities than others, with some over lap. For the average exerciser, its important to train and develop both of these fiber types to stimulate the full spectrum of your lean mass. The goal being to develop lean mass to increase metabolism, resting energy expenditure, burn more fat, and store less. Most of us today would like a lean athletic physique. However, alot of exercisers either do excessive amounts of muscle wasting cardio, which I discussed in my Cardio vs. Resistance Training blog, or they do too many repetitions of less than stimulating resistances. Nobody wants to "bulk up" these days. Bulking up, requires high calorie consumption, good genes, and great training. Conventional wisdom however, training light resistances to achieve slim lean looks, is not supported by science. High reps, low weight does not mean high reps, no weight. You need to stimulate your type one and two fibers by attacking their specific energy system. To do this, type 1 fibers need to be trained to fatigue with repetitions schemes of 15-25 repetitions or 20-60 seconds. Type 2 fibers should be trained at high loads appropriate to reach failure within 6 or less repetitions or 20 or less seconds. Stimulating both fibers and training within both energy systems is more stimulating to your body and your mind. For better muscle tone trying adding more resistance and fewer reps to your routine.