Over two-thirds of American adults are overweight or obese (National Health and Nutrition Examination Survey, 2004), with many estimates even higher (ACSM 2010). People must be more than 20 percent heavier than the recommended bodyweight for their height to be considered obese, yet bodyweight based on height chart assessments alone does not identify how much extra fat a person is carrying. Another method that does not identify body fat but rather uses bodyweight relative to height (kg/m2) is the body mass index (BMI). The National Institutes of Health (2007) use BMI values between 25 and 29.9 and those greater than 30 for classifying people who are overweight and obese, respectively. When skinfold measurements, or the more precise method of underwater weighing, are used to determine body-fat percentage, values that exceed the normal range by at least 5 percent are considered obese. In older populations, ACSM (2010) has suggested that satisfactory body-fat values for men and women age 50 to 59 are between 10 and 22 percent and 20 and 32 percent, respectively. Average body-fat values reported by the Cooper Institute for men age 60 to 69 and 70 to 79 are 22.6 and 23.1 percent, respectively, and those for women are 27.9 and 28.6 percent, respectively (ACSM 2010). Although girth measurements may also be used with older adults, they may not be as helpful because there are no well-established values for persons over 56 years of age. Regardless of the method used for assessing body composition, the lifestyles of many Americans clearly contribute to their weighing too much.
It is also easy to understand why many senior men and women are debilitated by obesity—nonexercising adults lose over 5 pounds (2.3 kg) of muscle and add about 15 pounds (6.8 kg) of fat each decade, bringing about an increase in body fat that may be 50 percent greater than the increase in bodyweight (Evans and Rosenberg 1992). Thus, older clients may come to you with simply too much fat and too little muscle, which makes every one of their physical tasks more strenuous, almost as if they are driving a semitrailer truck with a motor scooter engine. Fortunately, sensible strength training can remediate this situation (Campbell et al. 1994; Westcott 2009).
Because of the weight and size of their bodies, obese people have difficulty moving, including getting up, getting down, and engaging in all types of ambulatory activities. In choosing equipment, then, obese adults typically prefer upright or recumbent stationary cycles that support their weight instead of treadmills and stair-climbing machines that do not. Therefore, for your overweight clients, try to include machine exercises that can accommodate their larger frames and that are structurally sturdy enough to support their weight (plus that of the load or weight that they are using). Avoid exercises such as the machine hip/leg press because of the challenges it presents in getting into position to perform the exercise as well as simply getting into and out of the machine.
When working with obese clients, be sure that the equipment can accommodate their weight. Most manufacturers provide a weight limit in the product manual; if they do not, contact them to ascertain the weight limit for each piece of equipment that heavier clients will use. Free-weight exercises that require lifting dumbbells instead barbells from the floor to start an exercise may be easier. The width of the free-weight bar may also be too narrow to allow proper performance of exercises such as the biceps curl and back squat, indicating the need to use an Olympic-size bar, which is longer. Additional consideration should be given to selecting machine equipment that will be easy for overweight clients to get into and out of, and to avoiding some floor exercises (e.g., crunches, modified push-ups, stretching) that require clients to get down and up. If arthritis or joint pain is present, consider alternating the strength training exercises with lower-impact activities such as elliptical machines and stationary cycling activities or swimming. Regardless of the equipment used or the exercises being performed, programs for overweight and obese clients should include exercises that can be performed correctly and that clients feel more comfortable performing.