1. L E S S O N 1
Muscle Fitness Facts
Lesson 1

2. Can You . . .
. . . explain the differences between strength, muscular endurance, and power?
. . . describe how exercise principles apply to muscle fitness?
. . . describe the different types of muscle contractions?
. . . describe the characteristics of different muscle fiber types?

3. How are strength, muscular endurance, and power different?

4. Definitions Strength is the amount of force that a muscle can exert.
Muscular endurance is the ability to contract muscles many times without tiring or to hold a muscle contraction for a long time without fatigue.
Power is the ability to produce force quickly (strength × speed = power).

5. Physical Activity Pyramid

6. Key Terms for Muscle Fitness
Repetitions (reps): the number of consecutive times you do an exercise
Sets: one group of repetitions
Example:
Perform 8 push-ups, rest, perform another 8 push- ups, rest, and finish with 8 more push-ups
3 sets of 8 reps (push-ups)

7. Does building strength require different numbers of reps than building muscular endurance?

8. Muscular Endurance–Strength Continuum

9. Key Terms Muscle hypertrophy: growth in the size of muscles
1-repetition maximum (1RM): the amount of weight you can lift one time (best assessment of strength)
Calisthenics: exercises that use your body weight as the resistance

10. How would you apply the basic fitness training principles (overload, progression, specificity, rest and recovery) to muscle fitness?

11. Principle of Overload Do more than before!
Muscle fitness application: to become stronger and improve muscular endurance, strength, and power, a muscle must contract harder than normal

12. Principle of Progression
The amount and intensity of your exercise should be increased gradually.
Muscle fitness application: Gradually increase load or resistance over time in order to best improve your muscle fitness.
If you try to use too much resistance too soon, you can injure yourself.

13. Principle of Specificity
You get what you train for!
Muscle fitness application: The specific type of training that you perform determines which part of muscle fitness you build (strength, endurance, or power).
(continued)

14. Principle of Specificity (continued)
You build specific muscles by doing exercises specifically for those muscles.
Strength, muscular endurance, and power each have their own FIT formula.

15. Principle of Rest and Recovery
You need to give your muscles time to rest and recover after a workout.
Muscle fitness exercises for a specific muscle group are typically performed on only two or three days per week.

16. What are the two different types of muscle contractions?

17. Muscle Contractions
Isometric contractions occur when muscles contract and pull with equal force in opposite directions so that no movement occurs.
Isotonic contractions pull on your bones to produce movement. There are two types:
Concentric contractions: when the muscle shortens
Eccentric contractions: when the muscle lengthens

18. What are the different types of muscle fitness exercises?

19. Muscle Fitness Exercises
Isometric exercise
Pressing hands together, plank
Isotonic exercise
Biceps curl, push-up, bench press, squat
Plyometrics
Explosive jumping
Isokinetic exercise
Velocity of movement is kept constant by a machine

20. What are the different kinds of muscle fibers?
Describe the characteristics of each.

21. Muscle Fibers Slow twitch: less force, resist fatigue
Fast twitch: more force, fatigue quickly
Intermediate fibers: characteristics of both fibers
(continued)

22. Muscle Fibers (continued)
All muscles have a blend of the different muscle fibers.
Muscle with more slow-twitch fibers have better muscular endurance capabilities.
Muscles with more fast-twitch fibers have better strength and power capabilities.

23. Heredity and Muscle Fibers
Genetics (heredity) determine the muscle fiber composition of muscles.
People who inherit a large number of fast-twitch muscle fibers are especially likely to be good at activities requiring sprinting and jumping.
People who inherit a large number of slow-twitch muscle fibers are likely to be good at activities requiring sustained performance, such as distance running and swimming.
(continued)

24. Heredity and Muscle Fibers (continued)
Training can affect muscle fiber function.
Specific (anaerobic, strength, power) training can shift slow-twitch fibers to have characteristics more like intermediate fibers.
Specific (aerobic) training can shift fast-twitch fibers to have characteristics more like intermediate fibers.
Regardless of your genes, you can increase your strength, muscular endurance, and power with proper training.

25. Absolute vs. Relative Strength
Absolute strength is your 1RM score (the most amount of force you can produce).
Larger people typically have higher absolute strength.
Absolute strength is important for some athletic positions.
Relative strength is your strength adjusted for body size (1RM divided by body weight).
Relative strength is important for most athletes because carrying too much body weight (even muscle) can impair performance.

26. Science in Action: Resistance Exercise Among Youth
Not so long ago, some experts thought that muscle fitness exercises were unsafe and inappropriate for preteens and teens.
Experts now provide evidence that, when done properly, PRE provides health benefits for teens similar to those for adults.
(continued)

27. Science in Action: Resistance Exercise Among Youth (continued)
Benefits of muscle fitness:
Being able to work and play with little fatigue
Reduced risk of chronic disease
Reduced risk of injury and muscle pain or soreness,
Improved muscle fitness and sport performance
Psychological well-being
Improved bone fitness that reduces the risk of osteoporosis
Reduced risk of back pain
Improved posture (look your best)