Chapter7

Muscular Strength and Muscular Strength and EnduranceEndurance

Chapter 7

ObjectivesObjectives Explain the importance of adequate muscular strength

levels in maintaining good health and well-being. Clarify misconceptions about strength fitness. Define muscular strength and muscular endurance. Identify the factors that affect strength. Understand the principles of overload and specificity of

training for strength development. Learn dietary guidelines for optimum strength

development. Become familiar with core strength training and realize

its importance for overall quality of life. Become acquainted with two distinct strength-training

programs – with weights and without weights.

Benefits of Strength Benefits of Strength TrainingTraining

Increased muscle strength and endurance Increased power Increased muscle tone Increased tendon and ligament strength Health benefits

Promotes weight loss and maintenance; Lessens the risk for injury; Prevents osteoporosis; Reduces chronic low-back pain and arthritic pain; Aids in childbearing; Improves cholesterol levels; Promotes psychological well-being; May help lower blood pressure and control blood sugar.

Muscular Strength and Muscular Strength and AgingAging

Importance for older adult population Contributes more to independent living

than any other fitness component (maintains ADLs)

Sarcopenia the loss of lean body mass, strength,

and function. (common as people age) helps to slow the age-related loss of

muscle function.

Muscular Strength and Muscular Strength and AgingAging

Enhanced quality of life It improves balance and restores mobility. It makes lifting and reaching easier. It decreases the risk for injuries and falls. It stresses the bones and preserves bone mineral

density, thus decreasing the risk for osteoporosis. Increases muscle mass or size, known as muscle

hypertrophy, thereby increasing metabolism Loss of muscle tissue as we age combined with

normal eating habits results in the formation of fatty tissue

Burns ~35 cal for every pound of muscle

Muscular Strength and Muscular Strength and AgingAging

Gender differences Endocrinological differences do not allow

women to achieve the same amount of muscle hypertrophy (size) as men

Men produce Testosterone Men also have more muscle fibers

Anabolic steroids and human growth hormones produce detrimental and undesirable side effects in women.

Change in Body Composition Change in Body Composition With Aerobic & Strength With Aerobic & Strength ProgramProgram

Changes in body composition Assess body composition regularly to monitor

changes in percent body fat rather than simply measuring changes in total body weight

Decreased adipose tissue is more obvious when combined with aerobic exercise.

Assessment of Muscular Assessment of Muscular Strength and EnduranceStrength and Endurance

Muscular strength The ability of a muscle to exert

maximum force against resistance Muscular strength is often determined

by the maximal amount of resistance (weight) an individual is able to lift in a single effort

one repetition maximum, or 1 RM Several body sites should be assessed

Muscular Strength: Muscular Strength: The Hand Grip TestThe Hand Grip Test

When time is a factor, the Hand Grip Test can be used to roughly estimate strength

An isometric test--involves a static contraction

If the proper grip is used, no finger motion or body movement is visible during the test

Assessment of Muscular Assessment of Muscular Strength and EnduranceStrength and Endurance

Muscular endurance Submaximal force repeatedly over time Depends on muscular strength

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

Muscular endurance test Upper body –

modified dip (men) or modified push-ups (women)

Lower body – bench jumps

Midbody – bent-leg curl ups or abdominal crunches

Muscular Endurance Muscular Endurance Scoring TableScoring Table

Assessment of Muscular Assessment of Muscular Strength and EnduranceStrength and Endurance

Muscular strength and endurance test Lift submaximal resistance as many

times as possible Six strength-training exercises

A strength/endurance rating is determined according to the maximum number of repetitions you are able to perform on each exercise

A Muscular Strength & A Muscular Strength & Endurance TestEndurance Test

Factors That Affect Strength Factors That Affect Strength – Neural Stimulation– Neural Stimulation

Motor unit Motor neurons control muscle activity A motor unit is a motor neuron and all

the muscle fibers it innervates As the number of fibers innervated and

frequency of stimulation increase, so does the strength of muscular contraction

Factors That Affect Strength Factors That Affect Strength – Neural Stimulation– Neural Stimulation

Motor units

Factors That Affect Strength Factors That Affect Strength – Neural Stimulation– Neural Stimulation

Types of muscle fibers Slow-twitch (red fibers)

Aerobic Fast-twitch (white fibers)

Anaerobic Proportion is determined genetically but

training can improve them Slow-twitch fibers are always recruited first.

As speed and force increase, fast-twitch fibers become more important.

Factors That Affect Strength Factors That Affect Strength – Overload – Overload

Achievement of strength gains Through increased ability of individual muscle

fibers to generate a stronger contraction. By recruiting a greater proportion of the total

available fibers for each contraction 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

Factors That Affect Strength Factors That Affect Strength – Overload – Overload

Procedures to overload in strength training

Increasing the resistance, number of repetitions, speed of repetitions, and volume.

Decreasing rest interval for endurance improvements or lengthening the rest interval for strength gains.

Using any combination of the above.

Factors That Affect Strength Factors That Affect Strength – Specificity of Training– Specificity of Training

Training must be specific to obtained desired effects Specific adaptation to imposed demand

(SAID) training 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

Principles Involved in Principles Involved in Strength TrainingStrength Training

Mode of training Isometric training

muscle contractions produce little or no movement as in pushing or pulling against an immovable object

A critical component of health conditioning programs for the back

Dynamic training muscle contractions produce movement as in leg extensions Strength is gained through the full range of motion

Consists of two phases: Concentric (positive resistance): the muscle shortens

as it contracts to overcome the resistance. Eccentric (negative resistance): the muscle lengthens

to overcome the resistance, allowing us to lower weights in a smooth, gradual, and controlled manner.

Principles Involved in Principles Involved in Strength TrainingStrength Training

Mode of training Isokinetic training Variable-resistance or

isokinetic machines equipped with mechanical devices that provide differing amounts of resistance, with the intent of overloading the muscle group maximally through the entire range of motion.

Principles Involved in Principles Involved in Strength TrainingStrength Training

Free Weights Require that the individual

balance the resistance through the entire lifting motion.

Are cheaper, allow variety of use, can be transported more easily, require balancing by using stabilizing muscles, and fit all exercisers.

Weight machines Are safer, provide some

exercises not possible with free weights, can program variable resistance, isolate muscles better, require less time to select weight, can limit range of motion for rehabilitation, and require less skill than free weights.

Principles Involved in Principles Involved in Strength TrainingStrength Training

Resistance A resistance of approximately 80 percent

of the maximum capacity (1 RM). 80 percent of 1 RM varies by repetitions

according to type of exercise (Table 7.4). Once the person can lift the resistance

more than 12 times, the resistance is increased by 5 to 10 pounds and the person again should build up to 12 repetitions. This is referred to as progressive resistance training.

Principles Involved in Principles Involved in Strength TrainingStrength Training

Sets Number of repetitions performed for a

given exercise 1 to 3 sets for the starting exerciser

Recovery time Needed to replenish ATP-CP system Usually 3 minutes for strength training. About 2 minutes for health-fitness training

Circuit training Alternating exercises by performing them in

a sequence of three to six or more exercises

Principles Involved in Principles Involved in Strength TrainingStrength Training

Frequency Strength training can be done through a total body

workout two or three times a week or more if a split body routine (upper body one day, lower body the next) is used

The muscles should be rested for about 2-3 days after a maximum workout to allow recovery

If not, the person may be overtraining and not reaping the full benefits of the program

Eight consecutive weeks of training are required to obtain significant strength gains

Guidelines for Various Guidelines for Various Strength-Training ProgramsStrength-Training Programs

Training VolumeTraining Volume Sum of all repetitions multiplied by the

resistances during a training session Used to quantify the amount of work

performed in a given training session Sets x Reps x Weight

High training volumes and low intensities are used to achieve muscle hypertrophy.

Low volumes and high intensities are used to increase strength and power.

Training VolumeTraining Volume Periodization

Used by athletes to achieve peak fitness and prevent overtraining.

Involves cycling of one's training objectives (hypertrophy, strength, and endurance).

With each phase of the program lasting 2–12 weeks.

Increases the volume no more than 5 percent from one phase to the next.

Plyometrics Plyometrics Explosive jump training incorporating

speed and strength training to enhance explosiveness

Objective Generate the greatest amount of force in

the shortest time Requires a solid strength base Higher risk for injuries than the

conventional modes of progressive resistance training

Strength GainsStrength Gains How quickly can strength gains be

observed? Studies reveal that most strength gains are

seen within the first 8 weeks of training Improvement is related to previous training

status 40% in individuals with no previous strength-

training experience 16% in previously strength-trained people 10% in advanced individuals

Strength Training Strength Training ExercisesExercises

Strength training without weights (Exercises 1–14, pages 256–260).

Strength training with weights (Exercises 15–37, pages 261–270). Exercises 15–27 are recommended for a

complete workout. Exercises 28–37 are supplemental or can

substitute for certain exercises numbered 15–27.

Stability ball exercises (Exercises 38–46, pages 270–273) Can be used to complement your workout.

Strength Training Strength Training ExercisesExercises

Changing exercises should be done to continue to challenge the muscles Can vary range of motion Create difficulty of exercise Avoiding monotony of doing the same

exercises over and over and over…

Major Muscles of the Human Major Muscles of the Human BodyBody

Dietary Guidelines for Dietary Guidelines for Strength Development Strength Development

During periods of intense strength training Increase protein intake from 0.8 g/kg body

weight to 1.5 g/kg body weight/day Additional 500 calories/day – complex

carbohydrates Snacks: carbohydrates + protein

Pre-exercise (30-60 minutes before exercise) Immediately following strength training 1 hour after training Post-exercise: ratio of 4-to-1 g carbohydrate

to protein

Core Strength TrainingCore Strength Training The "core" of the body includes the trunk

(spine) and pelvis. Core muscles include muscles of the

abdomen, hip, and spine. Many of the major muscle groups of the

legs, shoulder, and arms attach to the core.

A major objective of core strength training is to exercise the abdominal and lower back muscles in unison.

Pilates Exercise SystemPilates Exercise System A training program that uses exercises designed

to help strengthen the body’s core by developing pelvic stability and abdominal control coupled with focused breathing patterns Originally developed in the 1920s by Joseph

Pilates Exercises are performed either on a mat (floor) or

with specialized equipment to increase strength and flexibility of deep postural muscles

Intended to improve muscle tone and length, instead of muscle hypertrophy

Pilates training should be conducted by certified instructors with extensive Pilates teaching experience

Stability Exercise Balls and Stability Exercise Balls and Elastic-Band Resistive Elastic-Band Resistive ExerciseExercise

Stability exercise balls 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

Elastic-Band Resistive Elastic-Band Resistive ExerciseExercise

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

Sample Elastic-Band Sample Elastic-Band Resistive ExercisesResistive Exercises

Exercise Safety GuidelinesExercise Safety Guidelines Select exercises to involve all major

muscle groups Select exercises to strengthen the core Never lift weights alone Use proper lifting technique Maintain proper body balance while lifting Exercise larger muscle group before

smaller muscle groups

Exercise Safety GuidelinesExercise Safety Guidelines Exercise opposing muscles Breathe naturally Avoid holding your breath while

straining to lift Allow adequate recovery time Pay attention to any discomfort or pain

Exercise Safety GuidelinesExercise Safety Guidelines Use common sense Stretch after any strength-training

workout Consult physician before you start

Real Life StoriesReal Life Stories

Real Life Stories Real Life Stories Critical Thinking Critical Thinking QuestionsQuestions

1. What mistakes did Nathan make with his strength-training program?

2. Have you mastered proper technique in all of your strength- training exercises? Are there mistakes in form you have seen others make in the weight room? Can you list potential pitfalls of using improper form during strength training?

3. Discuss your personal feelings regarding strength training, including benefits and possible drawbacks for you from such a program.