Chapter 7
Principles of Muscular Strength Assessment and Prescription

1. Introduction

• Strength is crucial for performance in daily activities
• Strength also improves posture, personal appearance, and self image
• Strength also helps:
  1. Maintain muscle tissue
  2. Maintain higher resting metabolism
  3. Lesson the risk of injury
  4. Prevent lower back pain
  5. Prepare for childbearing

2. Strength and Metabolism

• Metabolism- The energy and material transformation within living cells
• An increase in strength means an increase in muscle mass
• Muscle tissue uses energy even at rest
• As muscle size increases do does resting metabolism
• Each pound of muscle tissue increases resting metabolism by 35 calories per day
• Strength may be the most important health-related component for older adults (helps with independent living)
• Metabolism doesn't have to slow with age -- We slow, NOT our metabolism!
• As lean body mass decreases, metabolism decreases
• If calorie intake stays the same and activity decreases, fat increases

3. Gender Differences
   • The average women is incapable of building large muscle mass through weight training (Due to the lack of testosterone and the number of muscle fibers)
   • Women with a natural physical advantage are more inclined to participate in sports
   • People associate this physical advantage with weight training causing them NOT to participate in weight training
   • Women bodybuilders "pump" extra blood into muscles by lifting immediately before competition
   • The muscles appear larger for several hours after "pumping"
   • About 80% of women bodybuilders have used steroids to develop muscle mass
   • Anabolic steroids- synthetic versions of testosterone
   • Side effects of steroids:
     • hypertension
     • fluid retention
     • decreased breast size
     • deepening of the voice
     • facial whiskers and body hair
4. Another benefit of strength training is a reduction of fatty tissue around muscles
   • People may often NOT loose weight weight or even gain weight
5. Assessment
   1. Strength- ability to exert maximum force against resistance
   2. Strength is assessed through determining the maximum amount of resistance one can lift with a single effort
   3. Endurance- ability to exert submaximal force repeatedly over time
   4. Endurance is assessed through determining the number of repetitions one can perform at a given submaximal resistance
   5. In strength training, several sites should be tested
6. Factors that affect strength
   1. Neural stimulation
      • A motor neuron (nerve) attaches to muscle fibers
      • Motor unit- A motor neuron and the fibers it stimulates
      • Stimulation of a motor unit causes fibers to contract "all-or-none"
      • Strength of contraction is determined by the number of fibers stimulated and the frequency of the stimulation
   2. Types of fiber
      • Slow-twitch (red)- A fiber which has a greater capacity for aerobic work
      • Fast-twitch (white)- A fiber which has a greater capacity for anaerobic work
      • The proportion of slow- and fast- twitch fibers is genetically determined
   3. Overload principle
      • Strength gains are achieved through an increased ability of the muscle fiber to generate a stronger contraction
      • Gains are also achieved by engaging a greater proportion of total available fibers
      • Overload principle- for strength to improve, demands placed on a muscle must be increased gradually (Strength training is also called "progressive resistance training")
   4. Specificity training
      • for a muscle to increase in strength or endurance, training must be specific to the desired outcomes
7. Principles involved in strength training
   1. Mode of training
      • Two types of training improve strength:
        • Isometric- A muscle contraction which produces NO movement (Pushing against an immovable object)
        • Isometric training doesn't require much equipment but strength gains are specific to the angle of contraction
        • Isotonic- A muscle contraction which produces movement (Moving a resistance)
        • Isotonic training is the most popular for strength training
          • Most daily activities are Isotonic
          • Can be conducted with or without weights
          • Movement is through a full range of motion
        • Other types of training
          • Variable resistance- overloads the muscle through the entire range of motion
          • Isokinetic- speed of the contraction is kept constant
   2. Resistance- weight lifted (This depends on whether the objective is strength or endurance):
      • Strength- 80% of maximum capacity (3 - 12 repetitions) -- Once 12 repetitions are achieved, increase the resistance
      • Endurance- 60% of maximum capacity (12 - 20 repetitions) -- Makes muscles look larger
   3. Set- A specific number of repetitions for a given exercise
      • As the number of sets increases so do fatigue and recovery time
      • A recommended program for beginners is 3 heavy sets proceeded by at least one warm-up set (warm-up at 50% of maximum capacity)
      • Recovery time between sets is about 3 minutes
      • Supersetting- working different muscle groups while others recover
   4. Frequency (how many sessions per week)
      • A total body workout is needed 3 times per week
      • A split-body routine can be done more frequently (upper body/lower body)
      • Muscles must be rested 2 or 3 days for recovery
      • 8 weeks of training are needed to see strength gains
      • 1 training session per week is needed for maintenance
8. Plyometrics- A training method which incorporates speed and strength to enhance explosiveness
   1. Attempts to take advantage of the stretch-reflex characteristic of the muscle (complimenting the muscle contraction)
   2. Has a higher risk for injuries as compared to other training methods
   3. Example exercises: (1)Box jumping, (2) Medicine ball
9. Setting up your own strength training program
   1. Muscle strength -- up to 12 repetitions
   2. Muscle endurance -- greater than 12 repetitions
   3. Exceptions are the abdominal and calf muscles (require more than 20 reps)
   4. Do three training sessions per week (on non-consecutive days)
   5. Do three sets of at least 6 - 10 exercises involving the major muscle groups
      • Quads
      • Hamstrings
      • Pecs (chest)
      • Biceps
      • Triceps
      • Deltoids (shoulders)
      • Abdominals
      • Calfs

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