1. Chapter 7 Muscular Strength & Endurance
Outline:
Benefits of Strength Training
Changes in Body Composition
Assessment of Muscular Strength & Endurance
Strength-Training Prescription
Strength Gains
Strength-Training Exercises
Dietary Guidelines for Strength Development
Core Strength Training
Exercise Safety Guidelines
Setting Up Your Own Strength Training Program
Chapter 7 Muscular Strength & Endurance

2. Muscular Strength & Endurance
A well-planned strength-training program will help to improve and maintain everyday functional physical capacity
Strength-training leads to increased muscle strength and endurance, muscle tone, tendon and ligament strength, and bone density

3. Benefits of Strength Training
Increasing strength:
Increases or maintains muscle and a higher resting metabolic rate
Encourages weight loss and maintenance
Decreases the risk for injury
Prevents osteoporosis
Reduces chronic back pain and alleviates arthritic pain
Aids in childbearing
Improves cholesterol levels
Promotes psychological well-being
May help lower the risk of high blood pressure and diabetes

4. Muscular Strength & Aging
Muscular strength may be the most important health-related fitness component in the older adult population
Good strength contributes more to independent living than any other fitness component
Older adults with good strength levels can successfully perform most activities of daily living

5. Muscular Strength & Aging
A common occurrence in aging is sarcopenia - the age-related loss of lean body mass, strength, and function
Gradual loss of muscle mass and frailty lead to falls and loss of function
Strength training helps to slow the age-related loss of muscle function
In some older adults, protein deficiency contributes to loss of lean tissue

6. Muscular Strength & Aging
Data indicates that strength training can enhance quality of life
Improves balance and restores mobility
Makes lifting and reaching easier
Decreases the risk for injuries and falls
Stresses the bones and preserves bone mineral density, decreasing the risk for osteoporosis
Increases muscle mass or size, known as muscle hypertrophy, thereby increasing metabolism

7. Selected Detrimental Effects from Using Anabolic Steroids

8. Changes in Body Composition
People, especially women, often become discouraged because they do not see quick results on the scale
Regularly determining body composition to monitor changes in percent body fat can offset discouragement

9. Assessment of Muscular Strength & Endurance
Muscular strength: The ability of a muscle to exert maximum force against resistance
Muscular endurance: The ability of a muscle to exert submaximal force repeatedly over time

10. Assessment of Muscular Strength & Endurance
Muscular endurance or “localized muscular endurance” largely depends on muscular strength as weak muscles cannot repeat an action several times or sustain it
Strength tests and training programs have been designed to measure and develop absolute muscular strength, muscular endurance or both

11. Assessment of Muscular Strength & Endurance
Muscular strength is often determined by the maximal amount of resistance (weight)--one repetition maximum, or 1 RM--an individual is able to lift in a single effort
1 RM is determined through trial and error
A true 1 RM might be difficult to obtain the first time an individual is tested as fatigue becomes a factor

12. Assessment of Muscular Strength & Endurance
Muscular endurance is often established by the number of repetitions an individual can perform against a submaximal resistance or by the length of time a given contraction can be sustained
In strength testing, several body sites should be assessed because muscular strength and endurance are both highly specific
A high degree of strength or endurance in one body part does not necessarily indicate similarity in other parts, so no single strength test provides a good assessment of overall strength
To make valid comparisons, you should use the same test for pre- and post-assessments

13. Strength-Training Prescription
Muscle cells can exert more or less force according to the demands placed upon the muscular system
If muscle cells are overloaded as in a strength-training program, the cells hypertrophy or increase in size
If demands on muscle cells decrease as in sedentary living or required rest because of illness or injury, the cells atrophy and lose strength
Muscular strength is important to develop and maintain fitness, health, and total well-being

14. Factors that Affect Strength
Physiological factors combine to create muscle contraction and subsequent strength gains
Neural stimulation
Type of muscle fiber
Overload
Specificity of training
Basic knowledge of these concepts is important to understand the principles involved in strength training

15. Types of Muscle Fiber The body has two basic types of muscle fibers:
Slow-twitch or red fibers
Fast-twitch or white fibers
Slow-twitch fibers have a greater capacity for aerobic work
Fast-twitch fibers have a greater capacity for anaerobic work, produce more overall force for quick, powerful movements as in strength-training activities

16. Types of Muscle Fiber
Genetics determines the ratio of slow- and fast-twitch fibers
Training increases the functional capacity of both fiber types
Strength training increases their ability to exert force
During muscular contraction, slow-twitch fibers are always recruited first
As force and speed of the contraction increase, fast-twitch fibers become important
Intense, powerful activity activates fast-twitch fibers

17. Overload Strength gains are achieved in two ways:
Increased ability of individual muscle fibers to generate a stronger contraction
Recruiting a greater proportion of total available fibers per contraction
These two factors combine in the overload principle - demands placed on a system must be systematically and progressively increased over time to cause improvement or development
Strength training is also called progressive resistance training

18. Overload Procedures used to overload in strength training:
Increasing resistance
Increasing number of repetitions
Increasing or decreasing speed of the normal repetition
Decreasing the rest interval for endurance gains or lengthening the rest interval for strength gains
Increasing the volume (total reps performed multiplied by the resistance used)
Using any combination of the above

19. Specificity of Training
Principle of specificity of training – for a muscle to increase in strength or endurance, the training program must be specific to obtain the desired effects
The principle is commonly referred to as SAID training (specific adaptation to imposed demands)
The SAID principle suggests that to improve specific sport skills, the strength training exercises performed should closely resemble the movement patterns used in that specific sport or activity
Understanding neural stimulation, muscle fiber types, overload, and specificity is required to effectively design a strength training program

20. Principles Involved in Strength Training
Principles necessary to develop a strength training program:
Mode
Resistance
Sets
Frequency
Volume of training
Key factor for success in muscular strength development is the individualization of the program according to these principles, the person’s goals, and the magnitude of the individual’s effort during training

21. Mode of Training
Two types of training methods are used to improve strength:
Isometric (static)
Dynamic
Isometric training: muscle contractions produce little or no movement as in pushing or pulling against an immovable object
Dynamic training: muscle contractions produce movement as in leg extensions
To increase isometric versus dynamic strength, static instead of dynamic training must be used

22. In isometric training, muscle contraction produces little or no movement

23. Dynamic Training Most popular mode for strength training
Strength is gained through full range of motion
Improvements are measured easily by the amount lifted
Dynamic training has two action phases when an exercise is performed
concentric or positive resistance
eccentric or negative resistance

24. Dynamic Training
Concentric phase - the muscle shortens as it contracts to overcome the resistance
Eccentric phase - the muscle lengthens to overcome the resistance
Both motions work the same muscle against the same resistance
Eccentric contractions work to lower weights in a controlled manner
Eccentric contractions are more effective in producing muscle hypertrophy but result in greater muscle soreness

25. Free Weights vs. Machines in Dynamic Training
Plate-loaded barbells (free weights) were the most popular weight training devices until the 1970s when strength-training machines became more popular
A debate rose over which of the two training modalities was better
Free weights require the lifter balance the resistance through the entire lifting motion, raising assumptions that additional stabilizing muscles are required to balance the resistance as it moves through the range of motion
Research has not shown any differences in strength development between the two exercise modalities
Muscles do not know the source of the resistance
Strength development is determined by the quality of the program and the individual’s effort during the program

26. Strength training can be done using free weights

27. Advantages of Free Weights
Cost - free weights are less expensive than most machines
Variety - can be used to perform many exercises to strengthen most muscles in the body
Portability - can be moved from one area to another
Balance - requires the lifter balance the weights through the entire range of motion
One size fits all - can be used by most everyone, whereas not everyone can use machines such as small women and adolescents

28. Advantages of Machines
Safety - rarely need spotters
Selection - a few exercises can only be performed with machines
Variable resistance - provided by most machines; free weights provide fixed resistance
Isolation - isolates individual muscles because stabilizing muscles are not required

29. Advantages of Machines
Time - less time is required because the resistance can be set quickly
Flexibility - provide resistance over a greater range of motion, contributing to more flexibility in the joints
Rehabilitation - small loads can be selected easily through a limited range of motion
Skill acquisition - learning a new exercise and performing it correctly are faster because the machine controls the direction of movement

30. Resistance Resistance or intensity is the amount of weight lifted
General recommendation for strength development
Resistance of about 80% of maximum capacity (1 RM); example, 1 RM is 150 lbs., resistance should be 120 lbs. (150 x 0.80)
Repetitions performed at a certain percentage of the 1 RM - depends on the amount of muscle mass involved and if it is a single or multi-joint exercise
Large muscle mass involvement and multi-joint exercises allow more repetitions

31. Resistance
Progressive resistance training - a gradual increase of resistance over a period of time
Individuals perform between 3 and 12 repetitions maximum for strength gains
If a person can not lift the resistance more than 12 times because volitional fatigue is reached before 12 repetitions, the weight is adequate for strength development
When the person can lift the weight more than 12 times, the resistance is increased by 5-10 pounds and the person again builds to 12 repetitions

32. Resistance
Strength development can occur using less than 80% of 1 RM and working below 3 RM or above 12 RM
ACSM recommends a range between 3 RM and 20 RM
The individual may chose the number of repetitions based on personal preference
Elite strength athletes work between 1 and 6 RM and vary number of repetitions
Bodybuilders use 60%-85% of 1 RM with 8-20 repetitions
General fitness requires about 10 repetitions to produce good results in strength, endurance, and hypertrophy

33. Sets Set is the number of repetitions performed for a given exercise
General fitness recommends one to three sets per exercise
Some data indicates that increases in strength, endurance, and hypertrophy occur between single and multi-set training, as long as the single set or at least one of the multi-sets is a heavy set performed to volitional exhaustion using an RM zone (8-12)

34. Sets
There is a limited number of sets the exerciser can do because of muscle fiber characteristics
Strength gains may be lessened by performing too many sets
Single set programs are preferable if time is a factor
Multi-sets can be used for multi-joint exercises and a single RM zone for single-joint exercises
Beginners should perform 1-2 light warm-up sets per exercise using about 50% of the 1 RM followed by 1-3 sets to near fatigue per exercise

35. Sets
Circuit training: Alternating exercises by performing them in a sequence of three to six or more exercises
To maximize strength gains, the program will be more time-effective if two or three exercises are alternated that work different muscle groups
The bench press, leg extension, and abdominal curl can be combined so that the person can go almost directly from one exercise set to the next without resting 2-4 minutes before preceding to a new set of a different exercise

36. Frequency
A minimum of 8 weeks of consecutive training is necessary to achieve significant strength gains
Once an individual has achieved a recommended health fitness strength level, one training session per week is sufficient to maintain it
Highly trained athletes must train twice a week to maintain their strength levels

37. Training Volume
Volume is the sum of all the repetitions performed multiplied by the resistances used during a strength-training session
It is used to quantify the amount of work performed in a training session
The total training volume can be obtained by totaling the volume of all exercises performed
An individual who performs three sets of six repetitions with 150 pounds has performed a training volume of 2,700 (3 x 6 x 150) for this exercise
Training volume can be modified by changing the total number of exercises performed by changing the number of sets per exercise or the number of repetitions performed per set
High training volumes and low intensities achieve muscle hypertrophy
Low volumes and high intensities increase strength and power

38. Training Volume
Periodization divides the season into cycles using a systematic variation in intensity and training volume for athletes to achieve peak fitness and prevent overtraining
Overtraining: An emotional, behavioral, and physical condition marked by increased fatigue, decreased performance, persistent muscle soreness, mood disturbances, and feelings of staleness or burnout as a result of excessive physical training
To avoid overtraining during periodization, the volume should not increase by more than 5% from one phase to the next
Periodization is becoming popular among fitness participants who want to achieve higher levels of fitness

39. Plyometrics
Plyometric exercise is explosive jump training incorporating speed and strength training to enhance explosiveness
Objective is to generate the greatest amount of force in the shortest time
Requires a solid strength base
Popular in sports that require powerful movements--basketball, volleyball, sprinting, jumping, gymnastics

40. Core Strength Training
The trunk (spine) and pelvis are the “core” of the body
Core muscles include abdominal muscles, hip muscles, and spinal muscles
These muscle groups are responsible for maintaining the stability of the spine and pelvis
Many major muscle groups of legs, shoulders, and arms attach to the core

41. Core Strength Training
A strong core allows a person to
Perform activities of daily living with greater ease
Improve sports performance through a more effective energy transfer from large to small body parts
Decrease the incidence of low back pain
Contributes to better posture and balance

42. Stability Exercise Balls
Large, flexible, inflatable ball used for exercises that combine Pilates with core strength training
Exercises are designed to develop abdominal, hip, chest, and spinal muscles by addressing core stabilization while the exerciser maintains a balanced position over the ball
Emphasis is placed on correct movement and maintenance of proper alignment
Primary objective is core strength and stability
Many stability exercises can be performed to strengthen other body areas

43. Elastic-Band Resistive Exercise
Elastic bands and tubing can be used as constant-resistance training
Help increase strength, mobility, functional ability, aid in rehab in injuries
Advantages include
Low-cost
Versatility - use at almost all angles/directions of range of motion
Large number of exercises to work all joints
Can be packed in a suitcase
Add variety to routine

44. Setting Up Your Own Strength-Training Program
Consult a physician if you have concerns regarding your ability to safely participate in a program (not advised for people with advanced heart disease)
Determine your stage of change
Choose training program
Keep a record of your training sessions
Base the resistance, number of repetitions and sets on your current strength-fitness level and available time for your workout