Chapter 13 Muscular Strength, Endurance, and Power ©2013, The McGraw-Hill Companies, Inc. All Rights Reserved Chapter Objectives After completing this chapter, you should be able to 1. Define muscular strength, dynamic strength, static strength, dynamic and static muscular endurance, and power. 2. State why muscular strength, endurance, and power should be measured. 3. Measure muscular strength, endurance, and power. 4. Describe responsibilities after the measurement of muscular strength, endurance, and power and prescribe activities to improve muscular strength and endurance. ©2013, The McGraw-Hill Companies, Inc. All Rights Reserved 13-2 Muscular Strength, Dynamic Strength, and Static Strength Muscular strength is the ability of a muscle or muscle group to exert maximum force. Dynamic strength is the force exerted by a muscle group as a body part moves (isotonic strength). Static strength is the force exerted against an immovable object; movement takes not take place (isometric strength). Both types of strengths are best measured by tests that require one maximum effort. ©2013, The McGraw-Hill Companies, Inc. All Rights Reserved 13-3 Dynamic and Static Muscular Endurance Dynamic muscular endurance is the ability of a muscle or muscle group to resist fatigue and to make repeated contractions against a defined submaximal resistance Static muscular endurance is the ability to maintain a certain degree of force over time. High-resistance, low-repetition program or lowresistance, high-repetition program? Must have some strength to develop endurance. ©2013, The McGraw-Hill Companies, Inc. All Rights Reserved 13-4 Muscular Power Muscular power is the ability to generate maximum force in the fastest possible time; ability to release maximum muscular force in an explosive manner. Power equal to the product of force times velocity. Force generated by muscular strength; velocity is the speed the force is used. Power usually measured by some type of jump, throw, or charge (vertical jump, shop put, or a charge at a blocking sled). ©2013, The McGraw-Hill Companies, Inc. All Rights Reserved 13-5 Why Measure Muscular Strength, Endurance, and Power? Muscular Strength 1. Strong muscles help protect the joints; less susceptible to sprains, strains, and other injuries. 2. Necessary for good posture (abdominal muscles, round shoulders, and low back pain). 3. Perform routine tasks more efficiently. 4. Increase changes for success in sports. 5. Decline in muscle strength can affect functions such as agility, balance, and coordination ©2013, The McGraw-Hill Companies, Inc. All Rights Reserved 13-6 Why Measure Muscular Strength, Endurance, and Power? Muscular Endurance 1. Perform daily tasks better; prevent end-of-day fatigue. 2. Maintain good posture; decrease likelihood of back problems and muscular injury while performing routine tasks. Muscular Power Often a characteristic of a good athlete, but is rarely necessary for performing daily tasks. ©2013, The McGraw-Hill Companies, Inc. All Rights Reserved 13-7 Responsibilities after Measurement • Should seek to help individuals who need to improve • Perform exercises on regular basis • Children usually do not need highly organized program; use activities that require them to move and lift body • Weight-training programs should be performed minimum of two days/week • Exercises and guidelines are provided at conclusion of chapter ©2013, The McGraw-Hill Companies, Inc. All Rights Reserved 13-8 Tests of Muscular Strength and Endurance In laboratory and rehabilitation setting, dynamometers, cable tensiometers, and electromechanical instruments may be used to measure muscular strength and endurance. Tests with Weight-Training Equipment Handgrip, knee flexion, foot placement, and all other considerations that may influence test performance must be standardized. Test must also be standardized for motivational considerations. ©2013, The McGraw-Hill Companies, Inc. All Rights Reserved 13-9 Tests of Muscular Strength and Endurance Conduct warm-up, avoid overworking, and observe safety precautions. American College of Sports Medicine states: 1.Participants should be familiarized with equipment and test procedures. 2. Participants should be provided a warm-up period. ©2013, The McGraw-Hill Companies, Inc. All Rights Reserved 13-10 Tests of Muscular Strength and Endurance ACSM (continued) 3. Standardization of performance position should be followed for all tests. 4. Adequate rest should be provided between tests. ©2013, The McGraw-Hill Companies, Inc. All Rights Reserved 13-11 Tests of Muscular Strength and Endurance Dynamic strength measured with one repetition maximum (1-RM). Relationship exists between body weight and weight lifted; maximum weight that can be lifted should be interpreted in relation to individual’s weight. Major muscle groups may be tested with the bench press, standing press, arm curls, and leg press. ©2013, The McGraw-Hill Companies, Inc. All Rights Reserved 13-12 Tests of Muscular Strength and Endurance Relative muscular endurance test - performer works with weight that is proportionate to the maximum strength of a particular muscle group or to body weight Absolute muscular endurance test - all performers work with the same amount of weight (the weight has no relationship to maximum strength or body weight of the test performer) ©2013, The McGraw-Hill Companies, Inc. All Rights Reserved 13-13 Tests of Muscular Strength and Endurance In a test for muscular endurance, weight should be lifted and returned without jerky movements. A 3-second cadence may be used to encourage continuous, smooth movement. A fixed percentage of 70% of the maximum strength may be used to test muscle endurance. Health fitness – should be able to perform 12 to 15 repetitions of each of the lifts tested Competitive athlete – should be able to perform 20 to 25 repetitions ©2013, The McGraw-Hill Companies, Inc. All Rights Reserved 13-14 1-Repetition Maximum (RM) Bench Press Test objective. Measure strength of arm extension muscles. Age level. Twenty through sixty-plus. Validity. Research shows 1-RM bench press is best weight lifting test for predicting total dynamic strength. Norms. Table 13.1 Scoring. Ratio; divide maximum weight lifted by performer’s weight in pounds. Free weight equipment preferred over Universal or Nautilus equipment. ©2013, The McGraw-Hill Companies, Inc. All Rights Reserved 13-15 1-Repetition Maximum (RM) Leg Press Test objective. Test strength of lower leg extension muscles. Age level. Twenty through sixty-plus. Face validity Norms. Table13.2 Scoring. Ratio; divide maximum weight pressed by performer’s weight in pounds. ©2013, The McGraw-Hill Companies, Inc. All Rights Reserved 13-16 YMCA Bench Press Test objective. Test dynamic muscle endurance of upper arm and shoulder girdle. Age level. Eighteen through 65-plus. Equipment. Metronome, 35-pound barbell, 80pound barbell, and weight bench. Norms. Table 13.3 Females use 35-pound barbell and males use 80pound barbell. 30 repetitions per minute. ©2013, The McGraw-Hill Companies, Inc. All Rights Reserved 13-17 Sit-ups and Curls-up • Sit-ups and curl-up tests described in this chapter emphasize speed of performance. • Similar tests described in chapter 15. • Few of the tests in chapter 15 require test be performed at a specified cadence. • Some specialists believe speed incorporates power; cadence procedure best measures muscular endurance. ©2013, The McGraw-Hill Companies, Inc. All Rights Reserved 13-18 Sit-Ups (Strength) Test objective. To measure strength of abdominal and trunk flexion muscles Age level. Twelve through college-age. Face validity; reliability and objectivity coefficients reported. Figure 13.1 illustrates the test. Johnson and Nelson (1986) provide norms for college students. ©2013, The McGraw-Hill Companies, Inc. All Rights Reserved 13-19 Sit-Ups (Endurance) Test objective. To measure abdominal strength and endurance Age level. Five through adulthood. Logical validity; reliability coefficient reported. Three types of sit-ups tests may be administered – arms crossed on chest, hands interlocked behind neck, or hands cupped behind ears . Figures 13.2 and 13.3 illustrate first two tests. Tables 13.4, 13.5, 13.6, and 13.7 report norms. ©2013, The McGraw-Hill Companies, Inc. All Rights Reserved 13-20 Abdominal Curls Test objective. To measure abdominal strength and endurance. Age level. Five through adulthood. Logical validity; reliability not reported. Table 13.8 reports norms for ages eighteen through thirty. ©2013, The McGraw-Hill Companies, Inc. All Rights Reserved 13-21 One Minute Curl Up Test objective. Measure abdominal strength and endurance. Age level. Five through sixty-plus. Face validity. Administered in same way as abdominal curl except test performer’s feet are held in place. Table 13.9 provides norms. ©2013, The McGraw-Hill Companies, Inc. All Rights Reserved 13-22 Pull-Ups Test for Strength Test objective. To measure arm and shoulder girdle strength. Age level. Twelve through college-age. Face validity; reliability and objectivity coefficients reported. Use weight plates and chair. Johnson and Nelson provide norms for college males. ©2013, The McGraw-Hill Companies, Inc. All Rights Reserved 13-23 Pull-Ups Test for Endurance Test objective. To measure arm and shoulder girdle strength and endurance. Age level. Nine through college-age. Face validity; reliability coefficient reported. Repeat pull-ups as many times as possible. Table 13.10 reports norms for males, ages nine through seventeen-plus. ©2013, The McGraw-Hill Companies, Inc. All Rights Reserved 13-24 Modified Pull-Ups for Endurance Test objective. To measure arm and shoulder girdle endurance. Age level. Ten through college-age. Face validity; reliability not reported. Figure 13.4 illustrates test. No norms reported. ©2013, The McGraw-Hill Companies, Inc. All Rights Reserved 13-25 Baumgartner Modified Pull-Ups Test objective. To measure arm and shoulder girdle, endurance, or both. Age level. Elementary through college. Face validity and construct validity; reliability coefficient reported. Figure 13.5 illustrates test. Table 13.11 reports norms for ages six through college-age. ©2013, The McGraw-Hill Companies, Inc. All Rights Reserved 13-26 Modified Pull-Ups Test objective. To measure upper body muscular strength and endurance. Age level. Five through eighteen. Figures 13.6a and 13.6b illustrate test. No norms reported. ©2013, The McGraw-Hill Companies, Inc. All Rights Reserved 13-27 Flexed-Arm Hang Test objective. To measure arm and shoulder girdle endurance. Age level. Nine through college-age. Face validity; reliability and objectivity coefficients reported. Table 13.12 reports female norms for ages nine through seventeen-plus. ©2013, The McGraw-Hill Companies, Inc. All Rights Reserved 13-28 Dip Test for Strength Test objective. To measure arm and shoulder girdle strength. Age level. Twelve through college-age. Face validity; reliability and objectivity coefficients reported. Johnson and Nelson (1986) provide norms for college males. ©2013, The McGraw-Hill Companies, Inc. All Rights Reserved 13-29 Dips Test for Endurance Test objective. To measure arm and shoulder girdle endurance. Age level. Ten through college-age. Face validity; reliability coefficient reported. No norms reported. ©2013, The McGraw-Hill Companies, Inc. All Rights Reserved 13-30 Push-Ups Test objective. To measure arm and shoulder girdle endurance. Age level. Ten through adulthood. Face validity; reliability not reported; objectivity coefficient reported. Table 13.13 reports norms for males ages twenty through sixty-nine. Some tests require that pushups be performed in a cadence or rhythmic pace. ©2013, The McGraw-Hill Companies, Inc. All Rights Reserved 13-31 Modified Push-Ups Test objective. To measure arm and shoulder girdle endurance. Age level. Ten through adulthood. Face validity; reliability coefficient reported. Figure 13.7 illustrates test. Table 13.13 reports norms for females ages twenty through sixty-nine; Canadian Physical Activity Fitness and Lifestyle Appraisal also includes norms. ©2013, The McGraw-Hill Companies, Inc. All Rights Reserved 13-32 Tests of Muscular Power Two types of muscular power may be measured : athletic power and work power. Athletic power – distance the body or an object can be propelled through space Work power – extraneous movements are controlled or eliminated, so that maximum effort must be put for by muscle groups being tested. Only three power tests presented. ©2013, The McGraw-Hill Companies, Inc. All Rights Reserved 13-33 Vertical Jump Test objective. To measure explosive leg power. Age level. Nine through adulthood. Validity, reliability, and objectivity coefficients reported. Table 13.14 reports norms for ages ten through seventeen-plus and table 13.15 reports norms for ages twenty through fifty-nine. ©2013, The McGraw-Hill Companies, Inc. All Rights Reserved 13-34 Standing Broad Jump Test objective. To measure explosive leg power. Age level. Six through college-age. Face validity; reliability coefficient reported. Table 13.16 reports norms for ages nine through seventeen-plus. ©2013, The McGraw-Hill Companies, Inc. All Rights Reserved 13-35 Medicine Ball Put Test objective. To measure upper body power. Age level. High school through adulthood. Validity and reliability coefficients reported. No norms reported. ©2013, The McGraw-Hill Companies, Inc. All Rights Reserved 13-36 Exercises to Develop Muscular Strength and Endurance The following guidelines should be observed when performing exercises to develop muscular strength and endurance. 1. Perform stretching and warm-up exercises before attempting muscular effort. 2. Perform the exercises that provide a mild overload first and gradually progress to the more difficult ones. ©2013, The McGraw-Hill Companies, Inc. All Rights Reserved 13-37 Exercises to Develop Muscular Strength and Endurance Guidelines (continued) 3. Unless otherwise indicated, begin with ten repetitions and add two or three repetitions each week until the desire number is reached. 4. Perform the exercises 3 to 5 days per week. ©2013, The McGraw-Hill Companies, Inc. All Rights Reserved 13-38 Exercises to Develop Muscular Strength and Endurance Exercises to develop muscular strength and endurance are described in text. The exercises require no special equipment and can be performed by children and adults. The exercises are for the: Posterior Upper Arms, Shoulders, Chest, and Upper Back Anterior Upper Arms, Shoulders, Chest, and Upper Back Abdomen; Lateral trunk; Lower Back and Buttocks; Lateral Hips and Thighs; Upper Legs; Lower Legs ©2013, The McGraw-Hill Companies, Inc. All Rights Reserved 13-39