People frequently write or talk about the physiological differences between muscle fibers (fast twitch versus slow twitch, oxidative capacity, etc.), but this information is generally not very useful to the typical fitness and health enthusiast. Some understanding of how your muscles work is certainly important, but most people don’t need to know all of the physiology in depth. Instead, I believe that understanding the basic functional differences between muscles provides more practical information than you would by learning a lot about muscle physiology.
When looking at the functional differences between muscles, you can certainly go very deep and examine how all the muscles in each joint work, but in the end, muscles generally fall into two different functional categories: prime movers and stabilizers. The prime movers are the muscles that actively create movement, while the stabilizers provide balance and support to your body.
Core muscles are usually the largest muscles in the body and include muscle groups such as the quadriceps and hamstrings (upper thigh), pectorals (chest), lats (back), biceps and triceps (arms), etc. They connect to your bones (via tendons) and create movement around a joint. For example, the biceps connects the upper arm to the lower arm (forearm), crossing the elbow joint, and when the biceps contracts, it brings the forearm closer to the upper arm. Since the biceps contraction creates this movement, it is considered a prime mover.
Stabilizers, as the name suggests, are more about stabilizing your body than creating movement. The stabilizers are smaller muscles, and in many cases, they are not even visible because they are so small or so deep below the superficial muscles. These muscles help keep your bones, joints, and muscles in proper alignment both during movement and while standing still.
Stabilizing muscles are also essential for maintaining good posture throughout life. For example, the stabilizing muscles of the mid and upper back work to keep the shoulders back and in line with the rest of the body. If those muscles become too weak or the chest and front shoulder muscles become proportionally too strong or tight, the shoulders will begin to round forward. If the stabilizing muscles are not strengthened to the point where they can reverse this change, then the rounding of the shoulders will progress and your posture will worsen over time, leading to additional problems.
Both prime movers and stabilizers play valuable roles in your body, and any complete training program will include exercises or workouts to improve both types of muscles. It’s also important to note that since prime movers and stabilizers have different muscle functions and demands, they need to be trained differently. Unfortunately, many people try to train stabilizers as if they were prime movers and possibly an increasing number of people don’t realize that stabilizers need to be trained at all.
This isn’t really surprising, because most people in the fitness industry and the media still focus on using exercise to improve the appearance of their bodies and rarely take the time to explain how training can improve the way they feel. your body works. It’s a common assumption that training will always improve the way your body works, but this is only partially true. A well balanced program will improve the way your body functions, but many programs are unbalanced or ignore important aspects that actually lead to physical dysfunction.
Improving stabilizer muscles is an example of something that is often left out of the average training program. Since stabilizers are so small, training them usually doesn’t cause any dramatic changes to your body’s appearance, so they don’t get much attention and are often ignored entirely. It’s very tempting to only train the prime movers, because they are responsible for most of the calorie burn and physical change. While most of your training time can be spent on prime movers, at least some stabilization training should also be included.
When doing resistance training (lifting weights, using exercise bands, etc.), the prime movers are typically trained by performing sets of exercises where each set typically contains between 3 and 15 repetitions, depending on your goals. of training. In general, lower reps and higher weight result in more strength gains, while higher reps and lower weight result in greater local muscular endurance. However, in both cases, the muscles are trained for a certain number of repetitions, usually until fatigued, and then there is a rest period so they can recover for the next set.
This type of training is effective because the prime movers generally only work for shorter periods (with the exception of long duration events), but the stabilizers often have to contract for hours every day. The difference is that the stabilizer muscles are designed to produce small, sustained contractions for prolonged stabilization as opposed to the brief, strong contractions of the prime movers. As a result, it is not necessary to train the stabilizer muscles to produce a greater amount of force for a short period of time.
The good news is that you can train your stabilizer and prime mover muscles at the same time, depending on the exercises you use. For example, using machines to work the leg muscles (leg press, leg extension, etc.) provides little benefit to the leg stabilizers, but exercises performed standing in a split position (one leg out forward and one leg back), on one leg, or on balance devices (Bosu, inflated discs, etc.) will challenge the stabilizer muscles along with the prime movers.
One thing to keep in mind is that when you do exercises that challenge your stabilizers, your prime movers won’t be challenged as much, because you won’t be able to use as much weight or perform as many repetitions as when you don’t use the stabilizers. This is because the energy that would be used to contract the prime movers is spent on stabilization and movement control. Also, her stabilizers may fail before her prime movers, if the stabilization demand of the exercise is high enough.
However, for most people, the benefits of including stabilization training far outweigh the negatives of having slightly less improvement in major movers. Unfortunately, there isn’t much incentive for people to include stabilization exercises, because they often don’t realize the importance of stabilizer muscles, at least not until they begin to experience problems associated with stabilizer malfunction. Furthermore, these problems generally do not begin to occur until mid-to-late life and are often considered normal parts of aging, rather than preventable or reversible muscle and joint problems.
For example, let’s go back to my previous example of a person who has rounded shoulders. It is common for older people to have rounded forward shoulders along with excessive curvature in the upper back and spine. In most cases, this is not a normal part of aging and is actually caused by a combination of poor muscle stabilizing function, lack of flexibility, general lack of muscle use, and postural changes that result from these problems.
When people make an effort to stay active, maintain their flexibility, and practice good posture throughout their lives, rounding of the shoulders and other postural changes can usually be avoided. Fortunately, if you haven’t done everything you should have done when you were younger, there is still hope. A comprehensive training program, including stabilization training that targets problem areas, can go a long way toward reversing and preventing many of the muscle, bone, and joint problems typically associated with aging.