Muscular Strength and Endurance

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Muscular Strength and Endurance. Muscular Strength ? The maximal force that a muscle can generate for a single maximum effort. It is usually assessed by measuring strength using a one-repetition maximum (1-RM) procedure with either free weights or some form of variable resistance weight machine.Mu

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Muscular Strength and Endurance

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1. Muscular Strength and Endurance/Flexibility Chapter 4 & 5

2. Muscular Strength and Endurance Muscular Strength – The maximal force that a muscle can generate for a single maximum effort. It is usually assessed by measuring strength using a one-repetition maximum (1-RM) procedure with either free weights or some form of variable resistance weight machine. Muscular Endurance – The ability of the muscle to exert a submaximal force repeatedly or continuously over time. Usually measured by determining the maximum number of repetitions that can be performed. (push-ups/curl-ups)

3. Basic Skeletal Muscle Characteristics Musculo-tendinious unit – consists of muscle belly and tendons. When a muscle contracts (shortens), it moves a bone by pulling on the tendon that attaches the muscle to the bone. Muscles consist of individual muscle cells or muscle fibers. They are connected in bundles. A single muscle is made up of many bundles of muscle fibers covered by layers of connective tissue that hold the fibers together. The muscle fibers are made up of smaller units called myofibrils. When the brain signals the muscle to contract, protein filaments within the myofibrils slide across one another causing the muscle fiber to shorten. (actin and myosin - Sliding Filament Theory)

4. Muscle Unit

5. Types of Muscle Fibers Muscle fibers vary in their structural and functional characteristics. Color of muscle fiber is one difference. CHICKEN vs DUCK

6. Types of Fibers Slow Twitch (Red) Type I – High capacity for aerobic energy supply. Very efficient in producing ATP. Fatigue resistant. Speed of contraction of slow twitch fibers is much slower than fast-twitch. They are adapted for low intensity, long duration activities. They utilize aerobic energy system for fuel. Fast Twitch (White) Type II – High capacity for rapid force development. Rely on anaerobic metabolism for fuel. They are explosive and powerful, but fatigue quickly.

7. Muscles Weight training causes the SIZE of the individual muscle fibers to increase by increasing the number of myofibrils. HYPERTROPHY– the development of large muscle fibers. Most muscles contain a mixture of slow and fast twitch fibers. Inactivity reverses the process called ATROPHY.

8. Motor Units To exert force, the body will recruit one or more motor units (nerves connected to fibers) to contract. There can be anywhere from 2 to 100’s of fibers in each unit. The number of motor units recruited depends on the amount of strength required. Small weight ? Few motor units Large weight ? More motor units Strength training improves the body’s ability to recruit motor units. (Muscle Learning), thus increasing strength even before muscle size increases.

9. Motor Units

10. BENEFITS OF RESISTIVE TRAINING Increased muscular strength, endurance Increased muscle size (hypertrophy) Increased flexibility or range of motion Decreased body fat Increased lean body mass Increased metabolism Improved physical appearance Increased performance in activities Assists in prevention of osteoporosis

11. Source: Karl Weatherly/Getty Images (courtesy of McGraw-Hill Higher Education) Source: Karl Weatherly/Getty Images (courtesy of McGraw-Hill Higher Education)

12. Assessing Muscular Strength and Endurance Muscular strength assessed by determining repetition maximum (1 RM), the maximum resistance that can be lifted once Muscular endurance assessed by counting the maximum number of repetitions of a muscular contraction

13. Training Principles Overload – A gradual increase in the frequency, duration, or intensity of the activity must occur is any physiological adaptation is going to occur. For resistive training, this principle specifically suggests that for greater gains in strength, endurance or power to occur there must be a manipulation of these factors. For endurance, increase the number of repetitions in a set, reduce the recovery time between sets or a combination of the two. For strength, increase the resistance or load, while restricting the number of repetitions in a set to 10 or lower. In each case, over time the muscle will adapt to the changes and alter its structure and/or function, leading to greater gains.

14. Training Principles Specificity – The human body adapts to how it is being trained. The systems of the body will physiologically adapt, specifically to the type and nature of exercise training. How the body adapts, and how much it improves, is directly related to how hard, and in what manner, it is trained. Example – If you want a stronger upper body, you must train the chest, back, shoulders, and arms. If you want bigger quadriceps, you must train them! If you want to increase muscular strength, you need to follow the guidelines for strength development – more weight, less reps. For endurance, less weight, more reps.

15. Training Principles Reversibility – Periods of interrupted training will cause, in time, a reduction in strength/endurance. Muscle tissue will not retain, for any length of time, any gains in strength or endurance associated with resistive training if training is discontinued or drastically reduced. Atrophy – A reduction of muscle size. This is a result of reduced cross sectional area of individual muscle cells (size), from lack of training or a decrease in the number of cells, which is more associated with aging. Rate of atrophy due to detraining is approximately 1% per week, dependent on the nature and extent of detraining. For example, total bed rest could be more damaging than just quitting your resistive training program.

16. Types of Muscular Contractions Isometric (Static) – Contractions that generate muscle tension, but no change in the length of the muscle or movement of a joint. Example – tighten the abdominal muscles while sitting still. Isometric exercises develop strength only at or near the joint angle where they are performed, not through the entire joint ROM. Used to strengthen muscles after injury or surgery when movement of a joint could delay healing. For maximum gains hold the isometric contraction for 6 seconds and repeat 5-10 times.

17. Types of Muscular Contractions Isotonic (Dynamic) – Involves applying force with movement. Muscle contractions occur while muscles change length. Most popular type of exercises for increasing strength. Can be performed with free weights, machines, or your own body weight. Concentric – Contractions that occur when a muscle shortens a “positive” contraction. Eccentric – Contractions that occur when a muscle lengthens – a “negative” contraction.

18. Factors Affecting MS&E Training Muscle size Strength training does not increase the strength of contraction of the muscle cells, but rather increases in strength result from a proportional increase in the diameter or size of the muscle cell. Gender Women will not experience as much hypertrophy as men will. This is due to lower levels of testosterone. Age Loss of skeletal muscle tissue is associated with aging, however the greatest losses are related more to physical inactivity and sedentary lifestyle and may be preventable and/or reversible.

19. FITT PRINCIPLES Frequency – Training with weights should be 2-3 nonconsecutive days/week. Muscles require a 24-48 hour rest between workouts. Intensity – The amount of weight (resistance) lifted. This determines how your body will adapt to weight training and how quickly changes will occur. For strength, may use 80% of 1RM for 1-8 repetitions. Higher amount of weight ? Less Repetitions For endurance, use 40-60% of 1RM for 15-20 repetitions. Lower amount of weight ? More Repetitions For general fitness, use 70% of 1 RM for 8-12 repetitions.

20. FITT Principle for Strength Training Figure 4.4 Figure 4.4

21. FITT PRINCIPLES “Time” of Exercise (Repetitions and Sets)- to improve fitness, you must do enough repetitions of each exercise to FATIGUE your muscles. The number of repetitions needed to cause fatigue depends on the amount of weight lifted. For a general fitness program for both strength and endurance, complete 8-12 repetitions of 8-10 different exercises, balancing the muscle groups. (Ab and calf exercises may require more repetitions.) Set – Refers to the number of repetitions of an exercise. Start with 1-2 sets, and build up to increase strength. Allow enough rest time between sets for the muscles to work at a high enough intensity. Can work a different muscle group during the rest period to save time.

22. Type or Mode of Exercise – For overall fitness include exercises for your neck, upper back, shoulders, arms, chest, abdomen, lower back, thighs, buttocks, and calves – about 8-10 exercises in all. Balance between agonist (the muscle contracting) and antagonist (the opposing muscle which must relax and stretch) muscle groups. Example – If you do leg extensions (quadriceps), also do leg curls (hamstrings). Work the large muscle groups or multiple joints before working small muscle groups. Example – A chest press (chest, arms) should be performed before a lateral raise (deltoids). See back of chapter for exercises.

23. Systems of Training SET SYSTEM – Most popular type of training. Person does an exercise for a given number of repetitions, or a set, then rests before performing another set. SUPERSETS – An exercise set for a particular muscle group is followed by an exercise for the opposing muscle group. (biceps/triceps) SUPER MULTIPLE SET – Same concept as supersets, but the lifter completes all of the sets for a given muscle group, then completes the same number of sets for the opposing muscle group. SPLIT ROUTINE – Requires a great amount of time and work. Lifter alternates muscle groups worked each day, and works out more days/week. Example – M, W, F work arms, legs and abs; T, Th, Sa, work chest, shoulders and back.

24. Systems of Training PYRAMID SYSTEM – Adding weight until the lifter can complete only one repetition. Example – Bench press with a set of 10 reps, then add weight, complete 8-9 reps, add weight, complete 6-7 reps continuing until the final set is 1 repetition. (Light to Heavy) Can also pyramid down from heavy to light weights, increasing the repetitions as weight is removed. NEGATIVES – Emphasis is placed on the eccentric part of the exercise. Slower repetitions are suggested. (Muscle soreness is usually a result.) SUPER SLOW – Both concentric and eccentric movements are slowed down to achieve maximum contractions.

25. To start: Choose a weight with which you can do 8–12 repetitions with good form To progress, use the “two-for-two” rule: If your goal is 8-12 repetitions, add resistance when you do more than 14 repetitions at your previous two workouts Maintain good form at all times Track your progress

26. Safety Considerations 1. WARM up prior to the workout. 2. Breathe properly. Breathe out with strenuous position, and in with less strenuous position. DON’T HOLD BREATH. 3. Use spotters with free weights in any exercise where you could lose control of the weight. 4. Always use lock-collars on bar ends so plates don’t fall off. 5. Use proper lifting techniques

27. Machines ~Safe ~Convenient ~Easy to Use ~Don’t need spotter ~Rapid, effortless change of resistance ~Controlled range of motion ~Provide both positive and negative resistance ~Expensive ~Require a lot of space Free Weights ~Requires more balance, coordination ~Allow for a free range of motion ~Versatile ~Provide positive and negative resistance ~Require a number of muscle groups to work together when lifting ~May require a spotter ~Require time and effort to adjust resistance.

28. Muscular System Figure 4.6aFigure 4.6a

29. Muscular System Figure 4.6BFigure 4.6B

30. A Caution About Supplements and Drugs

31. A Caution About Supplements and Drugs Supplements taken to increase muscle growth Anabolic steroids Human chorionic gonadotrophin (HCG) Growth hormone Dehydroepiandrosterone (DHEA) and androstenedione Insulin and insulin-like growth factor (IGF-1) Beta-agonists Protein, amino acid, and polypeptide supplements and so-called metabolic optimizing meals

32. Side Effects of Anabolic Steroids Liver damage and tumors Reduced HDL High blood pressure, heart disease, cancer Depressed immune function Psychological disturbances Depressed sperm and testosterone production; breast development in males Masculinization in women and children Premature closure of bone growth centers

33. A Caution About Supplements and Drugs Supplements taken to speed recovery from training Creatine monohydrate Chromium picolinate Substances taken to increase training intensity and overcome fatigue Amphetamines Caffeine

34. A Caution About Supplements and Drugs Substances taken to increase endurance Erythropoietin Darbepoetien Substances taken to aid weight control Diethylpropion, phentermine Caffeine, PPA, ephedra Dinitrophenol Diuretics

35. Evaluating Dietary Supplements Do you need a supplement at all? Is the product safe and effective? What studies have been done? What has the research shown? Can you be sure that the specific product is of high quality?


37. FLEXIBILITY Flexibility – Defined as the range of motion (ROM) of a single joint or a group of joints. It is specific to each joint. The amount of movement is largely determined by the tightness of muscles, tendons, and ligaments that are attached to the joint. Benefits: Reduce muscle soreness Reduce muscle tension Reduce risk of low back pain Improve muscle performance Improve posture Improve muscle coordination Reduce the risk of injury

38. Source: DynamicGraphics/JupiterImages (courtesy of McGraw-Hill Higher Education) Source: DynamicGraphics/JupiterImages (courtesy of McGraw-Hill Higher Education)

39. Types of Flexibility Active (Dynamic) Flexibility – “The degree to which the force of a muscle contraction can move a joint.” A muscle is stretched by a contraction of the opposing muscle. Involves movement. Dynamic shoulder flexibility would affect your ability to swing a golf club. Important for daily activities and sports. Passive (Static) Flexibility – Refers to the ability to assume and maintain an extended position at one end or point in a joint’s range of motion. It involves no muscle contraction. An outside force or resistance provided by yourself, a partner, gravity or a weight helps the joints move through their ROM. Easier to measure than dynamic flexibility and is usually how we refer to flexibility.

40. What Determines Flexibility? Joint structure—joints vary in direction and range of movement Joint capsules = semielastic structures that give joints strength and stability but limit movement Muscle elasticity and length Collagen = white fibers that provide structure and support Elastin = yellow fibers that are elastic and flexible Titin = muscle filament with elastic properties

41. Muscle Elasticity and Length

42. Factors That Affect Flexibility Joint Structure and related connective tissue – One cannot change the joint structure and the range of motion of each joint will vary. But, the length of the resting muscle fibers can be developed. Soft Tissue – Muscle tissue, connective tissue, skin, scar tissue, fat tissue can all affect flexibility. Age – Aging decreases the natural elasticity of the muscles, tendons and joints resulting in stiffness. Sedentary lifestyles, common with aging, also affect flexibility. Gender – The differences tend to be joint specific and do not always favor women, which is a common perception. Muscle temperature – Warmed muscles stretch better than cold muscles and are less prone to injury. Pregnancy – Due to release of relaxin, there is a change in the elastic properties which improves muscle and joint flexibility.

43. FITT PRINCIPLES FREQUENCY – minimum of 2-3 days/week; 5-7 days/week may be better. INTENSITY – Slowly stretch warm muscles to the point of slight tension or mild discomfort. TIME – Hold the stretch for 10-30 seconds; repeating 3- 5 times. Relax and breath. TYPE – Stretch the major muscle groups exercised. Refer to the end of the chapter for exercises.

44. Proprioceptive Neuromuscular Facilitation (PNF) Most popular PNF stretching is the contract-relax stretching method, in which a muscle is contracted before it is stretched. The muscle being stretched is held in an isometric contraction first, then passively stretched. This also works when the opposing muscle is contacted prior to the passive stretch. Example – Stretching the hamstring – Contract the hamstrings, relax the hamstrings, contract the quadriceps, stretch the hamstrings. PNF is an effective way to increase flexibility. Usually requires a partner. PNF protocol should include 4 repetitions of each stretch, 3-5 days/week.

45. Static vs Ballistic Stretching Static stretching is the preferred method of stretching. A stretch is held to the point of slight tension or mild discomfort, but not pain. This allows for the development and retention of muscular flexibility. Ballistic (Bouncing) Stretching is the most dangerous of the stretching procedures. It may lead to muscle soreness or injury.

46. Stretching Techniques

47. A Flexibility Workout Figure 5.2 Figure 5.2

48. The Lower Back Low Back Pain has a direct relationship to lifestyle and wellness behaviors. Proper lifestyle choices can help prevent LBP. Sedentary lifestyles contribute to loss of muscular strength, endurance, and a limited ROM. Low Back Pain is the number one physical complaint by individuals ages 25-60 in the U.S. Second most common ailment for job absenteeism for ages 30-60. It contributes for 25% of days lost for the entire work force. LBP will affect 60-80% of the American and European population at some point. $50 billion will be spent each year by government and industry for LBP (job absenteeism, disability payments, worker’s compensations, disability insurance, medical and legal fees) Most pain occurs in the lumbar (lower) and sacral region because it bears the majority of your weight.

49. Low-Back Health Function of the spine Provides structural support for the body Surrounds and protects the spinal cord Supports body weight Serves as attachment site for muscles, tendons, ligaments Allows movement of neck and back in all directions

50. Skeletal System

51. Structure of the Spine 7 cervical vertebrae in the neck 12 thoracic vertebrae in the upper back 5 lumbar vertebrae in the lower back 9 vertebrae at the base of the spine fused into the sacrum and the coccyx (tailbone)

52. Structure of the Spine Figure 5.3Figure 5.3

53. Vertebrae Vertebrae consist of a body, an arch, and several bony processes Intervertebral disks = elastic disks located between adjoining vertebrae; consist of a gel- and water-filled nucleus surrounded by fibrous rings; serve as shock absorbers Nerve roots = base of pairs of spinal nerves that branch off the spinal cord

54. Vertebrae and Intervertebral Disk Figure 5.4Figure 5.4

55. Core Muscle Fitness Core muscles include those in the abdomen, pelvic floor, sides of the trunk, back, buttocks, hip, and pelvis Core muscles stabilize the spine and help transfer force between the upper body and lower body Lack of core muscle fitness can create an unstable spine and stress muscles and joints Whole body exercises and exercises using free weights or stability balls all build core muscle fitness

56. Causes of LBP The most common cause of LBP is physical inactivity! Poor posture Faulty body mechanics Stressful living and working habits Weak musculature – especially the abs Poor flexibility in the lower back and hamstrings Smoking

57. Prevention of LBP Exercise regularly to strengthen your back and abdominal muscles. Lose weight, if necessary, to lessen strain on your back. Avoid smoking (which increases degenerative changes in the spine). Lift by bending at your knees, rather than the waist, using leg muscles to do most of the work. Receive objects from others or platforms near to your body, and avoid twisting or bending at the waist while handling or transferring it.

58. Avoid sitting, standing, or working in any one position for too long Maintain a correct posture (sit with your shoulders back and feet flat on the floor, or on a footstool or chair rung. Stand with head and chest high, neck straight, stomach and buttocks held in, and pelvis forward). Use a comfortable, supportive seat while driving. Use a firm mattress, and sleep on your side with knees drawn up or on your back with a pillow under bent knees. Try to reduce emotional stress that causes muscle tension. Be thoroughly warmed-up before engaging in vigorous exercise or sports. Undergo a gradual progression when attempting to improve strength or athletic ability.

59. Treatment of Low Back Pain Physical Activity – Only 1% of all back patients need surgery. Most rehabilitation and prevention is lifestyle related. Maintain a normal weight. Excess abdominal weight can lead to lordosis and poor posture. Participate in regular aerobic exercise. Participate in regular muscular strength and endurance activities, especially for the abdominal and back regions. Incorporate lower back and hamstring flexibility exercises. Work all the planes of motion.

60. Managing Acute Back Pain Sudden back pain usually involves tissue injury Symptoms: Pain, muscle spasms, stiffness, inflammation Treatment: Ice, then heat OTC medication (ibuprofen or naproxen) Moderate exercise

61. Managing Chronic Back Pain Considered chronic if lasts longer than 3 months Symptoms: Stabbing or shooting pain, steady ache accompanied by stiffness, pain that is localized or that radiates to other parts of the body Treatment: Many options, including medication, exercise, physical therapy, massage, acupuncture, education, and surgery

62. Tip of the Day Results in training occur with consistency and effort – a lifestyle habit!

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