Muscle Development

What is it?

• Frequency - How often an individual lifts weights must be managed appropriately in order to see gains in muscle mass. If one should lift too frequently, they will not have time to recover and then rebuild stronger muscles. If one should fail to lift frequently enough, there will not be enough stimulus to illicit long term gains in muscle.
• Sleep - The body performs most of its recovery while sleeping. An individual who is not getting enough sleep will not be providing enough opportunity for recovery and will find it difficult to gain muscle.
• Intensity - How hard one works in the weight room effects how effective they are at recruiting all of their muscle fibers. The greater the number of fibers recruited, the greater the growth stimulus, assuming appropriate recovery is provided for.
• Genetics - The ratio of slow twitch to fast twitch muscle fibers plays a large role in how much muscle an individual is capable of developing. Someone with a majority of fibers that exhibit slow twitch characteristics will have high endurance, but the potential to develop only moderate muscle mass. An individual with a majority of fibers with fast twitch characteristics will have the potential to develop considerable muscle mass, but low endurance.
• Diet - A poor diet can prevent muscle growth. In this model we assume perfect diet.

Understanding the model

This model attempts to simulate these effects with a cross sectional portrayal of a muscle at the level of the muscle fibers. When the observer activates a muscle fiber through resistance training, the fiber releases a chemical signal that results in a surge of hormones at the location of the fiber. These hormones affect the fiber development as mentioned above and will dissipate over time.

In this model there is one turtle breed, the MUSCLE-FIBERS.

The patches may be thought of as the cellular fluid that contains the anabolic and catabolic hormones. The brighter the green, the more anabolic (muscle building) the environment. The brighter the yellow, the more catabolic (muscle destroying) the environment.

How to use it

• SETUP: Sets up the model
• GO: Runs the model

• LIFT?: Decides whether or not the person is actively weight lifting

• INTENSITY: How hard the lifter is working. The greater the intensity, the greater the number of muscle fibers that will be fatigued each workout session.
• HOURS-OF-SLEEP: The amount of sleep a person gets effects how quickly the body breaks down the hormones.
• DAYS-BETWEEN-WORKOUTS: The frequency of the workouts effects how much time the body has to recover and then over-compensate from the last workout
• %-SLOW-TWITCH-FIBERS: How likely each fiber is to possess slow twitch characteristics.

• MUSCLE DEVELOPMENT VS. TIME: The sum of all fiber sizes over time
• HORMONES VS. TIME: The average hormone content of each patch

Things to Try

1. Run the model at its default settings. What eventually happens to the amount of muscle mass? Why?
2. Overtraining occurs when the body is not allowed to recover completely from the last exercise session before being trained again. This causes stagnation of muscular development, and in extreme cases, muscle loss. What types of conditions can lead to overtraining? What is the best way to recover from overtraining? What steps can be taken to avoid it?
3. Many undertake weight training in an effort to build the maximum amount of muscle they are capable of. Find the best method for achieving this. How must it vary over time? Why is it important to take one's current level of condition into consideration when choosing a resistance training program?
4. An issue rarely addressed in conventional training is that of genetic ability. A major factor effecting this the proportion of slow twitch vs. fast twitch muscle fibers a person possesses. Slow twitch fibers provide for greater endurance, fast twitch greater strength and size.
5. Attempt to obtain maximal muscular development with the %-SLOW-TWITCH slider set at 90% and then 10%. How do the results one can obtain vary with genetic ability? Training methods? What does this suggest about the average person following the routines of genetically gifted professional bodybuilders?

Extending the Model

1. In order to ensure you have achieved maximum muscular development, add a pen entitled MAX-MUSCLE to the MUSCLE DEVELOPMENT plot. Now modify the DO-PLOTTING procedure to use the MAX-MUSCLE pen to plot the sum of the MAX-SIZE value of all MUSCLE-FIBERS.
2. Nutritional quality can have a major influence on the results obtained from training. Modify the model to allow for this influence. Add a NUTRIENT variable to the MUSCLE-FIBER breed. Add a NUTRITIONAL-QUALITY slider to the model. Now modify the GO procedure to call a OBTAIN-NUTRITION function that releases nutrients into the patches. Finally, alter the GROW procedure to use the available nutrients when adding size to a muscle fiber.
3. Real life creates many inconsistencies in the average person's strength training program. Add a variance function to the model that randomly generates nights of less sleep and extra rest days between workouts to reflect these inconsistencies. Add a switch to allow the user to turn this variance on or off. Add a slider to allow the user to adjust the level of variance. What effect do these inconsistencies have on muscular development?

Design Tradeoffs

Credits and References