4 questions | Applied Sciences homework help

1. Be prudent about the amount of exercise per- formed. Do not attempt an overly intense exercise

program. Progress gradually at the start. High‑resistance exercises should not be done more often than roughly every 36 hours—every other day is a practical guideline. Any stretching should be done after warming up. 5. Add physical activity to your daily routine. When- ever possible, for example, walk instead of riding and climb stairs instead using an elevator or escalator. 6. It is advantageous to have specific goals that can be evaluated periodically. These could include achiev- ing or maintaining a specified body weight, resting heart rate, blood pressure, or blood lipid profile or achieving a specified level on a field test (e.g., a 15‑minute run, 25 pull‑ups, 75 pounds bench‑pressed). Some experts believe that aerobics has been oversold at the expense of muscle‑building. ACSM suggests that, in addition to aerobic exercise, individuals should engage in weight training at least twice a week, performing 8 to 10 different exercises to strengthen the large muscles of the chest, arms, back, and legs. When done correctly, this can increase strength, speed, flexibility, and muscle endurance. It can also improve a person’s appearance and confidence. Many people have difficulty sustaining an exercise program. Changes in schedule (e.g., vacations, special events), illnesses, bad weather, and other interruptions can scuttle a program. The key to maintaining a healthful lifestyle is not “willpower” but motivation. People are more apt to sustain an exercise program if they exer- cise for the sake of personal appearance (bodybuilders, weight‑control enthusiasts); to maintain or improve their ability to perform at sports (avid skiers, mountain climbers, rock climbers, swimmers, tennis tournament players); to recover health (cardiac rehabilitation pa- tients, women recovering from the effects of childbirth); because their social life centers around activities which are improved by keeping fit (bowling, golf, curling, softball); or because their job description requires that they pass periodic fitness tests (firefighter, police officers, military personnel). Most sports activities alternate in intensity with bursts of energy and periods of relative inactivity. Table 13‑3 indicates how various sports activities relate to fit- ness goals. This type of information can be misleading, however. For instance, the contribution that swimming makes to cardiovascular fitness can vary greatly. Com- petitive swimmers gain cardiovascular fitness from their intense training, but recreational swimmers may not. Some people stop exercising out of boredom. Bore- dom can be prevented by careful activity selection and timing. Some people prefer certain times of the day. Some enjoy seeing the sun rise or set. Some prefer the effects of exercise in the morning, whereas others like Chapter Thirteen Fitness Concepts, Products, and Services 265 phYsiCal aCtivitY guidelines For aMeriCans: KeY reCoMMendations8 Table 13-2 For Safe Physical Activity

• Understand the risks but be confident that physical activity is safe for almost everyone.
• Choose to do types of physical activity that are appropriate for their current fitness level and health goals, because some activities are safer than others.
• Increase physical activity gradually over time whenever more activity is necessary to meet guidelines or health goals. Inactive people should “start low and go slow” by gradually increasing how often and how long activities are done.
• Protect against injury by using appropriate gear and sports equipment, looking for safe environments, following rules and policies, and making sensible choices about when, where, and how to be active.
• People with chronic conditions and symptoms should consult their health‑care provider about the types and amounts of activity appropriate for them.

For Pregnant and Postpartum Women

• Healthy women who are not already highly active or doing vigorous‑intensity activity should get at least 150 minutes of moderate‑intensity aerobic activity a week during pregnancy and the postpartum period. Preferably, this activity should be spread throughout the week.
• Pregnant women who habitually engage in vigorous aerobic activity or are highly active can continue physical activity during pregnancy and the postpartum period, provided that they remain healthy and discuss with their health‑care pro- vider how and when activity should be adjusted over time.

For Adults with Disabilities

• If able to do so, get at least 150 minutes a week of moderate‑ intensity, or 75 minutes a week of vigorous‑intensity aerobic activity, or an equivalent combination of moderate‑ and vigorous‑intensity aerobic activity. Aerobic activity should be performed in episodes of at least 10 minutes and, prefer- ably, should be spread throughout the week.
• If able, do muscle‑strengthening activities of moderate or high intensity that involve all major muscle groups on 2 or more days a week.
• If unable to meet the guidelines, engage in regular physical activity consistent with abilities; avoid inactivity.
• Adults with disabilities should consult their health‑care provider about the amounts and types of physical activity that are appropriate for their abilities.

For People with Chronic Medical Conditions

• Adults with chronic conditions can obtain important health benefits from regular physical activity.
• When adults with chronic conditions do activity according to their abilities, physical activity is safe.
• People with chronic conditions and symptoms should consult their health‑care provider about the types and amounts of activity appropriate for them.

For Adolescents and Children

• Children and adolescents should do 60 minutes (1 hour) or more of physical activity daily.

Aerobic: Most of the 60 or more minutes a day should be either moderate‑ or vigorous‑intensity aerobic physical activ- ity, and should include vigorous‑intensity physical activity at least 3 days a week. Muscle-strengthening: As part of their 60 or more minutes of daily physical activity, children and adolescents should include muscle‑strengthening physical activity on at least 3 days of the week. Bone-strengthening: As part of their 60 or more minutes of daily physical activity, children and adolescents should include weight‑bearing physical activity (such as walking, jumping, or running) on at least 3 days of the week.

• Young people should be encouraged to participate in activi- ties that are age‑appropriate, enjoyable, and offer variety.

For Adults

• All adults should avoid inactivity. Some physical activity is better than none, and adults who participate in any amount of physical activity gain some health benefits.
• For substantial health benefits, adults should do at least 150 minutes (2 hours and 30 minutes) a week of moderate‑ intensity, or 75 minutes (1 hour and 15 minutes) a week of vigorous‑intensity aerobic physical activity, or an equivalent combination of moderate‑ and vigorous intensity aerobic activity. Aerobic activity should be performed in episodes of at least 10 minutes, and preferably, it should be spread throughout the week.
• For additional and more extensive health benefits, adults should increase their aerobic physical activity to 300 min- utes (5 hours) a week of moderate intensity, or 150 minutes a week of vigorous intensity aerobic physical activity, or an equivalent combination of moderate‑ and vigorous‑intensity activity. Additional health benefits are gained by engaging in physical activity beyond this amount.
• Adults should also do muscle‑strengthening activities that are moderate or high intensity and involve all major muscle groups on 2 or more days a week, as these activities provide additional health benefits.

For Older Adults (Age 65+)

• When older adults cannot do 150 minutes of moderate‑ intensity aerobic activity a week because of chronic condi- tions, they should be as physically active as their abilities and conditions allow.
• Older adults should do exercises that maintain or improve balance if they are at risk of falling.
• Older adults should determine their level of effort for physi- cal activity relative to their level of fitness.
• Older adults with chronic conditions should understand whether and how their conditions affect their ability to do regular physical activity safely.

Part Three Nutrition and Fitness266 to break up their day with a run at noon, or relax after work, or run before bedtime. Some find it helpful to lis- ten to music, whereas others prefer the sounds of nature or other aspects of life. Some prefer to exercise with a partner or a group, whereas others prefer to do it alone. Indoor exercisers may find that watching television holds their interest. The key point is that the surroundings may make the difference between maintaining or giving up a program. A survey of 21,750 Consumer Reports readers found that successful exercisers tended to choose the most convenient time of day (56%), exercise near home or work (48%), exercise outdoors (42%), join a health club (32%), and/or exercise with friends or family (24%).11 If physical activity is substantially reduced, many of the effects of exercise training on fitness will diminish within 2 weeks and will disappear within 2 to 8 months if significant activity is not resumed.12 Stretching Exercises Stretching exercises are effective in increasing flexibility, and thereby can allow people to more easily do activities that require greater flexibility. Shoulder stretches are particularly useful for swimmers because they enable the arms to be optimally placed for power strokes. Muscles are arranged in sets that are antagonistic to each other. Muscle spasms can occur when the strength and flexibility of antagonistic muscle groups are too far out of balance. For example, low‑back pain can occur when the back muscles are considerably stronger and less flexible than the abdominals. Exercises that strengthen the abdominals and stretch the lower back can help prevent a recurrence. The muscles should be completely warmed up be- fore flexibility exercises are performed. For this reason, stretching fits best at the end of an exercise session. It is widely believed that stretching can prevent injuries and prevent or reduce the soreness that occurs after doing movements to which the body is not adapted. This seems like common sense, yet there is little scien- tific support for these beliefs.8 Cochrane reviews, for example, have found “insufficient evidence” to suggest that stretching exercises prevent injuries in runners13 and have “minimal or no effect” on the muscle soreness experienced after activities performed by healthy young adults in laboratory settings.14 Assessing Exercise Intensity The demand exercise places on the heart can be measured and expressed in metabolic equivalents (METs). A MET is the amount of oxygen consumed while a person sits at rest—approximately 3.5 ml of oxygen per kg of body weight per minute. Performing a 2‑MET activity will raise oxygen consumption to 7 ml/kg, while a 3‑MET activity will triple the energy demand. Blair15 lists these MET values for various common activities: Activity Cardiorespiratory Strength Muscle Endurance Flexibility Aerobics, high‑impact VM M VM M Aerobics, low‑impact M‑VM S‑M M‑VM M Aqua exercises L S‑M M M Basketball VM S‑M M M Bicycling VM M M S‑M Bowling L L L L Calisthenics S‑M S S‑M S Dancing (vigorous) VM S‑M M M Golf S‑M S S S Jogging VM S‑M M S‑M Rope jumping VM M M‑VM S Swimming VM S‑M M M Tennis M‑VM S‑M VM S‑M Walking S‑M L‑S S‑M L *The extent of benefits from any sport depends on frequency, duration, resistance, and muscles involved. Key: VM = very much, M = much, S = some, L = little. Modified from Kusinitz I and others. Physical Fitness for Practically Everybody. Mt. Vernon, N.Y., 1983, Consumer Reports Books. Fitness Contributions oF various aCtivities* Table 13-3 Chapter Thirteen Fitness Concepts, Products, and Services 267 moderate intensity (3 to 4.9 mets): Calisthenics, golf (not rid- ing in a cart), weightlifting, recreational volleyball, walking at 3 to 4 mph (15 to 20 minutes per mile) Hard intensity (5 to 6.9 mets): Aerobic dance, doubles tennis, ice or roller skating, slow‑paced swimming, walking at 4.5 to 5.5 mph (10.9 to 13.3 minutes per mile) very Hard intensity (over 7 mets): Running, fast‑paced swimming, rope jumping, singles tennis, competitive racquetball Figure 13‑2 shows additional MET values. MET values can be used to guide doctors who pre- scribe exercise programs for patients recovering from heart attacks or other cardiovascular problems. For ex- ample, if a 5‑MET level of exertion on a stress test does not cause symptoms, it is unlikely that the heart will be strained by exercise at home. Balance Training Balance training involves exercises that are designed to improve the ability to withstand challenges from postural sway or destabilizing stimuli caused by self‑motion, the environment, or other objects. People at risk of falls should do balance training 3 or more days a week and do standardized exercises from a program demonstrated to reduce falls. Examples of these exercises include backward walking, sideways walking, heel walking, toe walking, and standing from a sitting position. The exercises can increase in difficulty by progressing from holding onto a stable support (like furniture) while doing the exercises to doing them without support. It is not known whether different combinations of type, amount, or frequency of activity can reduce falls to a greater degree. “Mind-Body Exercise” “Mind‑body exercise” is purported to “unify” the mind and body through training of motor coordination and awareness of body sensations. Ives and Sosnoff16 have identified 20 systems ranging from Pilates, which is vigorous enough for strength training, to others that in- volve minimal physical exertion. The three most popular methods are Pilates, tai chi, and yoga. Pilates is a series of low‑impact flexibility, muscular‑ endurance, and breathing exercises, most of which start from a supine position and involve lifting a combination of limbs, head, and back. The more complicated ones require the use of springs and pulleys, rigged up on spe- cial equipment. Proponents claim the exercises stretch, strengthen, and “balance” the body. However, a 6‑month study of 32 participants found no statistically significant changes in truncal lean body mass, height, weight, or other body composition parameters or on self‑assessment of health. The authors concluded that although Pilates training may result in improved flexibility, its effects on body composition, health status, and posture are more limited and may be difficult to establish.17 Tai chi combines breathing exercises with stretches and dance movements that can provide relaxation and improve flexibility and balance.18 The extent to which it contributes to aerobic fitness depends on the intensity Running or figure skating 7:23 min/mile (12.9) Cross‑country skiing 9.5 min/mile (12.2) Jogging 8:35 min/mile (11.2) Soccer (10.3) Raquetball/squash (10.0) Karate (10.0) Swimming 41 sec/25 yds (8.9) Riding horse at a gallop (8.6) Kayaking (7.8) Touch football (7.5) Ballet (7.0) Tennis singles (6.7) Aerobic dancing (3.9–6.0) Golf, carrying clubs (5.1) Ice skating 15.5 mph (4.8) Tennis doubles (4.5) Ballroom dancing (4.0) Walking 20 min/mile (3.2) Yoga (3.2) Bowling (3.0) Golf, riding cart (2.5) Fishing from boat (2.3) Motorcycling (2.2) Mets Figure 13-2. Approximate metabolic equivalents (METs) of various recreational activities. Sitting at rest (1.0) Part Three Nutrition and Fitness268 and duration of the sessions. It is probably most useful for elderly unfit individuals. Yoga encompasses a large number of religious and quasi‑religious practices based on ancient Indian beliefs about human existence. Its philosophy postulates five “sheaths” of existence: the physical body, the vital body, the mind, the higher intellect, and the abode of bliss (universal consciousness). The vital body is said to be composed of prana, “life energy” that flows through invisible channels. Disease is said to arise through imbal- ance of the three lower sheaths. In the healthy state the positive energy of the highest sheath supposedly perco- lates through the lower ones and brings total “harmony” and “balance” to the mind, body, and spirit. It is possible to participate and benefit without buy- ing into the mystical belief system. The various styles of yoga that people use for health purposes typically combine physical postures, breathing techniques, and meditation or relaxation. Yoga can improve flexibility but is unlikely to provide other fitness benefits. Ives and Sosnoff16 caution: The field of mind‑body exercise is wide open, unregulated, and filled with grand promises. Our advice is to thoughtfully consider these methods but not to the exclusion of traditional strength, aerobic, and flexibility exercises. Injury Prevention Many people are injured yearly in sports and recreational activities. Injuries range from minor aches and pains to severe overuse syndromes, fractures, and connective tissue tears. In 2003, the U.S. Centers for Disease Con- trol and Prevention reported that Americans received medical attention each year for about 7 million sports or exercise‑related injury episodes.19 The most common problems are injuries due to overuse—wear‑and‑tear to the muscles, ligaments, tendons, and joints (Table 13‑4). Injury can also result from improper use of equipment or from use of equipment that is poorly constructed. The risks of injury are greater for sedentary indi- viduals and those who thrust themselves into activities that are either too strenuous, prolonged, or frequent. As Jones and others20 have noted: Excessive activity without adequate conditioning and suffi- cient rest equals trouble. . . . All changes in frequency, duration, and intensity of exercise should be gradual. Serious athletes and weekend warriors alike should undergo overall strength and flexibility training in addition to the specific techniques required by the particular sport or activity. Flexibility is an important component of fitness, as is general body strength. An overuse injury is a signal that the body is working against itself. Appropriate strengthening and flexibility exercises, as well as an organized, progressive exerCise-related injuries and illnesses Table 13-4 Body Part Ankle Back Calf Ear Elbow Eye Foot Head Hip, groin Knee Neck Shoul- der Thigh Injury or Symptoms Twists, sprains Strain, soreness, muscle spasms, disc herniation Achilles tendinitis, shin splints Swimmer’s ear (external otitis) Soreness at joint (tennis elbow) Conjunctivitis Blisters, jogger’s heel (plantar fasciitis) Accidental injury Pulled muscle Torn cartilage and other problems Tightness or soreness Bicipital tendinitis and other types of painful conditions of the joint Pulled hamstring muscle Contributing Factors Overtiredness Sudden lunges or twists when tired; improper lifting technique Overuse Inflammation due to prolonged expo- sure to moisture Overuse and poor technique Irritation from chlorine Overuse Blow to head from a fall Overuse, changes of exercise routine Overuse, changes of exercise routine Overworking of muscles Overuse or poor technique Inadequate warm‑up in sports involv‑ ing running, jumping, or twisting Activities Racquet sports, volley- ball, basketball Running, weightlifting Running, aerobics Swimming Racquet sports Swimming Running, jumping Cycling Running Running, weightlifting Cycling Swimming, tennis, baseball Football, racquet sports, soccer, sprints Chapter Thirteen Fitness Concepts, Products, and Services 269 increase in the duration and intensity of exercise, will help to cure the problem and prevent its recurrence. Well‑designed exercise programs include time for the body to recover. High‑resistance exercises such as heavy weightlifting or intense anaerobic activities (such as sprinting, jumping, competitive tennis, or competitive swimming) require 36 to 48 hours for full recovery. Aero- bic activities and light‑resistance exercises can be done daily (or even twice daily). Exercise programs usually become highly individualized and may vary considerably from season to season. Consumer Reports21 notes that because old injuries increase the risk of new injuries to the same muscles and joints, it is important to protect injured areas until they are completely healed. Table 13‑5 outlines sample programs that contribute to all‑around fitness, weight control, and recreational sports ability. personal trainers A qualified personal trainer can assess individual fitness, create goals based on the status of that assessment, and motivate the client to adhere to the program as outlined. A proper program should address both the exercise and nutritional components of the person’s lifestyle. Evans22 recommends choosing a trainer with an ac- credited bachelor’s, master’s, or doctoral degree in exer- cise science, kinesiology, exercise physiology, physical education, sport management, or something similar. Comprehensive training takes 2000 to 3000 hours and provides a solid background in anatomy, physiology, biomechanics, and exercise prescription techniques. Many credentials presented by people in the fitness industry are not meaningful. Some certifications may cover just specific exercise gimmicks and techniques for which promoters make claims that are not scientifically defensible. Table 13‑6 lists organizations that certify personal trainers and other types of instructors. Some of these organizations offer their own courses. Although these certifications are legitimate, most require far less training than is required to obtain a degree. Thus, a thorough investigation of a potential trainer’s credentials should consider the extent and type of training as well as the requirements for certification. Primary Goal Moderate‑level cardiorespiratory fitness High‑level cardiorespiratory fitness* Moderate‑level overall fitness High‑level overall fitness* Moderate‑level weight control High‑level weight control High‑level weight control and fitness* Bodybuilding Recreational sport performance saMple exerCise prograMs Table 13-5 Weekly Schedule Aerobic exercise 3 days (every other day) Aerobic exercise 5–6 days Mon‑Wed‑Fri: aerobic exercise Tues and Thur: weightlifting or other resistance exercise Sun‑Tues‑Thur‑Sat am: distance running Mon‑Wed‑Fri am: interval running† Sun‑Tues‑Thurs pm: lap swimming, weightlifting, or other resistance exercise Mon‑Wed‑Fri pm: raquetball, tennis, handball, or basketball Daily am: walk‑jog‑run Daily am and pm: walk‑jog‑run Daily am: aerobic activities Sun‑Tues‑Thurs pm: lap swimming, weightlifting, or other resistance exercise Mon‑Wed‑Fri pm: raquetball, tennis, handball, or basketball Sun‑Tues‑Thurs‑Sat: walk‑jog‑run Mon‑Wed‑Fri: high‑resistance training Daily am: walk‑jog‑run or bike Sun‑Tues‑Thurs‑Sat pm: participation in specific sport Mon‑Wed‑Fri pm: supplemental training for specific sport *High‑performance programs exceed what is needed to achieve a fitness level associated with good health. However, high‑level fitness may be desirable for achieving athletic prowess or for other reasons. †Interval running involves timed, fast‑pace runs over measured distances for 1.5‑ to 3‑minute periods, with walking until recovery in‑between runs. Part Three Nutrition and Fitness270 American College of Sports Medicine (ACSM) American Council on Exercise (ACE) Cooper Institute (CI) International Fitness Professionals Association (IFPA) National Academy of Sports Medicine (NASM) National Council on Strength & Fitness (NCSF) National Exercise and Strength Trainer’s Association (NESTA) National Exercise Trainer’s Association (NETA) National Federation of Professional Trainers (NFPT) National Strength and Conditioning Association (NSCA) organizations that CertiFY personal trainers Table 13-6 sports MediCine speCialists Most exercise‑related injuries are minor and will resolve with reduced activity levels or rest. A general rule for muscle soreness or joint pain is to continue exercising at a lower level of intensity if the pain or soreness goes away after warming up. If the pain persists or worsens, the exercise program should be discontinued until activi- ties can be comfortably resumed. A physician should be consulted if (a) pain is severe or persists, (b) movement of the injured part of the body is difficult or impossible, or (c) the injury does not appear to be healing. When professional care is needed, the best first source is probably one’s primary physician. Physicians who are certified in a primary‑care specialty can obtain a Certificate of Added Qualifications in Sports Medicine by taking 12 to 24 months of fellowship training and passing an examination given by the American Board of Medical Specialties or American Osteopathic Asssocia- tion. Several other types of professionals can offer advice about exercise programs, procedures, and equipment or provide services to people who are injured. Some work primarily by referral, and some practice independently: atHletiC trainer: Athletic trainers help people plan exercise programs. They can also work under physician supervision to help treat sports injuries. exerCise pHysiologist (ph.d. or m.s.): Someone who helps design exercise programs for healthy athletes, hospital pa- tients, or fitness club clients. Many are research specialists. Those who work in health clubs generally have a master’s degree. massage tHerapist (massotHerapist): A certified or licensed person who may help speed up recovery by stroking and kneading muscles. ortHopediC surgeon (m.d. or d.o.): A physician who special- izes in the diagnosis and treatment of problems of muscles, bones, joints, and the spine. pHysiCal tHerapist (p.t. or r.p.t.): A trained and licensed indi- vidual who helps maintain and restore function to injured limbs and joints using strengthening machines, various exercises, heat, and water; works closely with physicians in rehabilitation. podiatrist (d.p.m.): A person medically trained in the pre- vention, diagnosis, and treatment of injuries, disease, and abnormalities of the foot and ankle. sports nutritionist (r.d.): A registered dietitian or other nutritional specialist who helps with the nutritional needs of athletes. sports psyCHologist (ph.d. or m.s.): Someone who works with athletes and teams to provide stress relief and to help meet specific training and competition goals. exerCise equipMent and supplies Americans spend several billion dollars a year on ex- ercise devices. Some contribute greatly to physical fit- ness and safety, whereas others have little or no value. Consumers contemplating purchase or use of exercise equipment should consider whether the benefits to be derived will contribute to endurance, flexibility, strength, and cardiorespiratory efficiency. Consumers may also investigate whether similar benefits can be obtained without equipment or in a less expensive way. Most people who purchase exercise equipment waste money, largely because boredom sets in. A 1998 survey found that fewer than one‑third of machines bought by Con- sumer Reports readers who began exercise programs during the previous 4 years were still in use.23 It is important for consumers to clearly understand their fitness goals, to obtain expert help in using equipment, and to check the quality of items before purchasing them. Sites such as craigslist.org carry many ads for used equipment at low prices. Consumer Reports magazine and www.consumerreports.org periodically publish test results and buying and safety advice on exercise equipment. Exercise Bicycles More than 100 brands and models of exercise bicycles are available, most costing between $150 and $2000. The best ones have rigid construction, a comfortable seat, easily adjustable height, and smooth riding action. Three types are marketed. Regular upright bikes involve pump- ing with the legs to turn a flywheel linked to the pedals. Resistance to pumping is provided by a strap around the wheel or a set of caliper brake pads. The tighter the strap Chapter Thirteen Fitness Concepts, Products, and Services 271 or pads, the more difficult it is to turn the wheel, and the greater the workout. Dual‑action uprights have their handlebars linked to the pedals so they move back and forth as the bike is pedaled; these provide exercise for the arms and legs. Recumbent bikes are operated by sitting in a seat resembling the bucket seat of a car; the user may be more comfortable and have less strain placed on back muscles. Training stands, which support a regular bike and add a resistance device, cost less but will not provide an aerobic workout for someone in good shape. Elliptical Exercisers These are a cross between an exercise bike and a ski machine. They provide an effective cardiovascular work- out, especially for advanced beginner and intermediate exercisers. Cross-Country Ski Exercisers Cross‑country ski machines can help produce weight loss, stimulate interest in cross‑country skiing, and strengthen and firm many muscle groups, especially in the legs. When planning to purchase a cross‑country ski exerciser, look for smoothness of operation, overall stability, foot security, a fit that allows adequate adjust- ment for people of different height, ease of resistance adjustment, and quiet operation. Treadmills Motorized treadmills provide the same benefits as walk- ing or running outdoors with less chance of injury and regardless of weather conditions. Most treadmills permit the user to control the rigor of the workout by adjusting the speed and incline of the track. Low‑priced models (under $500) are inconvenient to adjust and are too short and/or too slow for jogging. Mid‑priced models ($500 to $1000) offer a long platform, higher speeds, and the abil- ity to adjust the incline conveniently. Some can be used for jogging, but they may not last long if the user weighs more than 150 pounds. High‑priced models ($1600 and up) are built more sturdily, are more convenient to ad- just, and have more electronic gadgetry. Nonmotorized treadmills are not recommended because they force the user to walk in an unnatural position. A study compared the exercise workload and how people felt when using a ski simulator, an exercise bike, a rowing machine, a stairstepper, and a treadmill for walking. The subjects of the study were healthy, young adult volunteers who were trained to rate their perceived degree of exertion. The researchers found that the treadmill produced the highest energy expenditure (and therefore the best aerobic workout) for each level of perceived exertion.24 Stair Steppers and Climbers Steppers are single‑action devices that work out only the lower body. Climbers offer upper‑body exercise with hand grips that can be pulled down and pushed up while stepping with the feet. With the better models, the feet move independently, which means that each leg must do the work of stepping without help from the other. Bicycles for Riding Consumer Reports classifies bicycles into four groups: comfort bikes (for leisurely recreational riding), moun- tain bikes (for riding on rugged trails), road bikes (for fast or serious mileage), and fitness bikes (those who simply want to burn calories or improve cardiovascular fitness, or for daily short‑haul commuting). Bicycle Helmets Studies have found that helmet use can substantially reduce the risk of head injury among cyclists. Yet only small percentages of children and adults wear one. Stan- dards required by law are set by the Consumer Product Safety Commission. A properly fitting helmet should tilt up or down very little when the straps are snug. Rowing Machines These devices can contribute to strength and cardio- vascular fitness if frequency, intensity, and duration are maintained. However, a high degree of motivation is needed to prevent boredom from use. There is some risk for people with back problems. High‑quality machines cost at least $250. Good equipment has sturdy tubing; parts that fit snugly together; a padded, contoured seat that slides smoothly; and double‑piston “oars” with adjustable tension. Table 13‑7 compares 20 widely advertised types of exercise products, many of which are questionable. Electronic Feedback Electronic monitors found on many exercise machines (or available as an accessory) provide feedback on heart rate, speed, miles pedaled or traveled, and calories burned. Devices that report distance, speed, repetitions, elapsed time, and heart rate are usually accurate. Those that report calories burned may have a large margin of error. Generally, the more gadgetry, the higher the cost. Portable monitors check the pulse during exercise to enable individuals to know whether they are performing at an appropriate pulse rate (usually 60% to 90% of maxi- mum). There are two types: (1) finger or earlobe sensor and (2) transmitter worn on the chest that broadcasts to a watch that provides the pulse readout. The finger or earlobe type is less expensive but less accurate. This Part Three Nutrition and Fitness272 CoMparison oF exerCise equipMent Table 13-7 Description Barbells: Forms and shapes vary in size and weight; made of iron, rubber, plas- tic; water‑ or sand‑filled Bicycle, stationary: A bicycle without the usual wheels that registers speed and dis- tance; can pro vide varying de grees of resistance; some also have rowing action Bull‑worker: Two spring‑loaded cyl inders about 3 feet long with handles at each end that telescope when compressed Bun and thigh rocker Chinning bar: Bar hung in doorway, at tached to ceil- ing or wall, or included in multiple equipment system Chest pull/chest expander: Heavy rubber or elastic bands or springs with handles on each end Exercise balls (also called fitness balls and stability balls): Soft, inflatable rub- ber balls 14 to 34 inches in diameter Grip strengthener: Rubber ball; fairly hard substance Jump rope: Made of cotton, nylon, polyester material, with handles Mini‑trampoline: Steel frame with tough vinyl cover, 34 x 10 inches Advertising Claims Tone muscles; very light; easy to store Permits aerobic fitness in home or office; promotes circula- tion, improves muscle tone and coordination; increases endur ance Isometric/isotonic exerciser; develops mus cles and builds body through push, pull, and press; easy to use; takes 70 seconds a day Does the job of six pieces of lower‑body gym equipment Create a strong back in no time. Isometric/isotonic exercise; no long, tiring workouts; tones and shapes all muscle groups in one fourth the time required for barbells and dead weights Total body conditioning; core strengthening; increase flex- ibility, balance, and coordina- tion; fun; safe; adds variety to workouts. Builds muscles in wrist/forearm by simply squeezing ball; also exercises toes and instep; great tension reliever Improves cardiorespiratory efficiency (CRE); leg muscle endurance/stamina Combines aerobic exercises to work on each muscle in body and heart; easier on knees than jogging; improves posture, balance, digestion; strengthens heart; enjoyable Comments Provide resistance exercise; especially use ful with other equipment; benefits de pend on types of exercise, amount of weight, and frequency of use. Loosely handled free weights are hazardous to fingers and toes Extent of resistance and intensity will de‑ termine benefits Perhaps some isometric value; limited to upper body, excluding abdominals; “70 seconds” ad vertising claim unreasonable Basically a squat machine that does one thing that can be done without costly equipment Benefits limited to upper body strength de‑ velopment; strenuous for the unfit; can be made eas ily and cheaply in a home work- shop Good isotonic trainer for upper body; pro‑ vides limited resistance exercise benefits; resistance exercise can speed up strength improvement, but time requirement can not be verified; does not provide isoki netic or isometric exercise Can help strengthen muscles of abdomen, hip lower back, buttocks, and pelvis; proper size, inflation, and exercise technique are needed to avoid injury; some brands have burst when overinflated Any round rubber object or other resistant substance will strengthen muscles; frequen- cy and duration important; no evidence of tension relief Improves CRE; develops leg strength; excel- lent activity with inexpensive equipment; can be homemade; weighted ropes available No effect on digestion; good if intensity is high; probably can benefit the unfit; must work very hard for aerobic effect; hazard of losing balance and falling; some claims are conjecture; less traumatic to the body than running or jumping on hard surfaces Chapter Thirteen Fitness Concepts, Products, and Services 273 CoMparison oF exerCise equipMent—Cont’d. Table 13-7 Description Multipurpose gyms; home fit- ness system/portable gym/ weight training complex: Contain various weight‑ training items such as a sit‑ up/slant board and leg lifts Orthopedic inversion ma- chine: Upside‑down stretch that relaxes back and abdominal muscles Push‑up aids: Pair of steel bars or handles that in- crease force needed to do push‑ups Sit‑up bar: Bar attached 6 inches from wall for hook‑ ing feet when exercising Slant board: Vinyl‑covered, padded board, 12 to 14 inches wide; can be tilted up or down; person lies on it when exercising Stair climber: Grasp handle and begin to step and pull, working upper body and lower body at same time Stairway stepping: 2‑, 4‑, 6‑, and 8‑inch blocks; 4‑inch high platform to step; plus video Stomach eliminators: Cross- bar with heavy spring attached; stirrups‑like foot grips Thigh machine: Bar 12 inches from floor, movable against some resistance by the arms and legs Tummy trimming/stomach trimmer: Wide rubber/elas- tic belt that tightens, shapes abdominal area Advertising Claims Permits full range of profes- sional gym exercises; over 50 simple exercises from heavy bodybuilding to general physical fitness; do leg lifts, leg curls, arm curls, and arm rowing Easy, safe; strengthens muscle; supports back; painless invert- ed abdominal curls; improves circulation; releases stress; adds energy and vitality Provides better, quicker results than ordinary push‑ups; allows greater range of motion Strengthens middle; shapes legs Firms muscles; orthopedically approved Work upper and lower body at same time; work every muscle group; for serious training Latest in low‑impact video; mixes stair climbing and jazz aerobics Slimmer, younger look in 2 weeks; flattens stomach; strengthens chest, arms, back, thighs Slims legs; tones and stretches all body parts; over 40 iso- tonic and isometric exercises Look inches slimmer instantly; flatten stomach; no diet; no exercise Comments Provides resistance exercise that can speed up strength development and fitness; limited cardiorespiratory involvement; body parts involved depend on choice of exercises; some equipment usable in small space in home; less costly equipment and programs are available May strengthen back muscles with some trunk value; no evidence to support release of stress or improve circulation; high‑cost item; some potential for injury Resistance may quicken benefits; whether better is unproven; same results can be achieved without equipment Especially helps tone abdominals if knees in bent position; “shaping of legs” claim is puffery; with feet locked, hip flexors are involved Greater benefit because of greater resistance from gravity than in flat sit‑ups; use of bar- bells and weights increases resistance and benefits; may be part of home gym equip- ment; knees should be bent during use Good aerobic activity; most muscles involved; limited arm and very limited abdominal and back involvement Good aerobic and strength activity; limited u

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