HOW MUSCLES WORK (dated for archive retreat)

........I found this on Las Cruces Fire Department site. It's been removed but I found it in my cache. One of my favorite articles for basic muscle understanding.

Fitness & Health \ Principles of Physical Conditioning

Having a basic understanding of how the muscles work and basic principles of conditioning makes for the designing of workouts that are much more effective and personalized. A firefighter can style his/her own workouts to suit his/her interests, strengths, and goals.

How Muscles work
Everybody is born with the same muscles, but the muscles are composed of varying proportions of 3 different types of muscle fibers. The muscle fibers are classified according to the fuels they burn and the manner in which they contract. One type of muscle fiber is designed for endurance activities (slow-twitch muscle fibers). A second type of muscle fiber is designed for strength and speed (fast twitch muscle fibers). The third type of muscle fiber lies somewhere in between the endurance and the strength/speed fibers. An individual's anatomical make-up, in reference to the proportion of fast-twitch to slow-twitch muscle fibers, is genetically determined. Also, it explains why some individuals are naturally better suited for running marathons while others are better suited for power lifting. The types of muscle fibers a person has, as well as how he/she trains, determines level of success in different types of sports. The three types of muscle fibers are described below.

1. Slow-twitch oxidative fibers (SO): These muscle fibers are aerobic. They use oxygen to burn glycogen and fat for fuel. SO fibers come into play in endurance activities such as distance running, cross-country skiing, and biking. These fibers are fatigue-resistant. Their ability to contract is limited only by the availability of fuel and the abilities of the cardiovascular system and the respiratory system to supply oxygen and remove metabolic by-products. Aerobic training increases the quantity of glycogen stored in the muscles. Also, it increases the capacity and efficiency of the cardiovascular and respiratory systems. Therefore, the more you train, the farther you can go!

2. Fast-twitch glycolytic fiber (FG): These muscle fibers are anaerobic. They do not require oxygen to contract. FG fibers use phosphocreatine and ATP, derived from glycogen, for fuel. The ability of these muscle fibers to contract is limited only by the accumulation of lactic acid and the body's ability to tolerate oxygen debt. FG fibers come into play in speed and power activities that last less than 30 seconds, such as sprinting and weight lifting. These activities require the expenditure of enormous amounts of energy in short periods of time. Anaerobic training increases a firefighter's ability to break down glycogen into ATP quickly and to accumulate greater oxygen debt before muscle failure. Also, anaerobic training causes the FG fiber to grow stronger and thicker.

3. Fast-twitch oxidative-glycolytic fibers (FOG): These muscle fibers lie somewhere between the SO fibers and the FG fibers. They use the small amount of oxygen that is available in the muscle tissue to burn glycogen for their energy supply. The FOG fibers are active in all-out activities that last from 30 seconds to 2 minutes, such as the 200 and 400 meter sprints, running stairs, boxing, rope jumping, and many things done on fire scenes (pulling a crosslay, ventilating a roof, dragging a victim, etc.). The FOG fibers' ability to contract is limited by the quantity of oxygen and glycogen present in the muscle tissue. Training increases the amount of time the FOG fibers can contract before going into oxygen debt.
In order to maintain an all-ready-achieved level of physical fitness, a firefighter must consistently train at the intensity level at which he/she is comfortable. However, to improve one's level of physical fitness, be it in the area of strength, endurance, speed, or power, one must work at a higher intensity level. This is known as the overload principle.
The Overload Principle states that an activity must always be upgraded to a consistently higher level through maximum or near-maximum stimulation in order to reach a higher level of conditioning. A higher level may be achieved by increasing the intensity, the duration, or the frequency of the training activities performed.

Finally, before you go sprinting up A-Mountain or bench pressing all of the plates in the gym, be aware of a few conditioning rules.
Ten Cardinal Conditioning Principles: (from Modern Principles of Athletic Training by Daniel Arnheim)
1. Warming Up. Proper and adequate body warm-up procedures should precede all work-outs. Possible warm-up activities include jumping rope, slow jogging, or step-ups.
2. Gradualness. Add small daily increments of work. Remember: It takes 6 to 8 weeks to get into top-level condition.
3. Timing. Prevent overdoing. Relate all workouts to the firefighter's general level of conditioning. Remember: The tired firefighter is prone to injury.
4. Intensity. Stress the intensity of the work rather than the quantity. Often, firefighters fail to work themselves hard enough in terms of intensity. They make the mistake of prolonging the workout rather than increasing the tempo or the work load. As the degree of training increases, the intensity of training must also increase.
5. Capacity level. The firefighter must expect from him/herself performance that is as close to his/her physiological limits as health and safety factors will allow. Only in working to capacity will the desired results and progress be achieved.
6. Strength. Develop strength as a foundation and a means of minimizing injuries and producing greater speed and on-scene capacity to work.
7. Motivation. Motivation is a prime factor in sports conditioning. Throw small changes into the conditioning program occasionally to prevent staleness, boredom and progress plateaus. Find a good workout partner if you lose motivation when exercising alone.
8. Specialization. Exercise programs should include exercises for strength, endurance, and flexibility. In addition, exercise geared to the demands of the job should be used to develop the large muscle groups and to improve any personal weaknesses.
9. Routine. A daily routine of exercise, on-duty and off-duty, should be established. Include time and activities which allow for recovery, relaxation, and stress relief.
10. Consistency. To maintain fitness throughout a 20 year career and beyond, a firefighter cannot take a hit-or-miss approach to his/her conditioning program.

Any firefighter in his/her 40's who can still perform as well or better than those fresh out of high school is not in such great condition by accident. It takes daily devotion to sound fitness programs and healthy eating.


Ranjan said...

this is awesome. thanks.

Renatas said...