Page 1 of 15http://spider.apa.org/ftdocs/ccp/1997/april/ccp652278.html 10/12/2000Effects of Group- Versus Home-Based Exercise in the Treatment of Obesity Michael G. PerriDepartment of Clinical and Health Psychology University of Florida A. Daniel MartinDepartment of Physical Therapy University of Florida Elizabeth A. LeermakersDepartment of Clinical and Health Psychology University of Florida Samuel F. SearsDepartment of Clinical and Health Psychology University of Florida Morris NotelovitzABSTRACTThis study examined the effects of 2 aerobic exercise regimens on exercise participation, fitness, eating patterns, treatment adherence, and weight change in 49 obese women undergoing a year-long behavioral weight loss program. Participants were assigned randomly to weight loss treatment plus either group- or home-based exercise. All participants were instructed to complete a moderate-intensity walking program (30 min/day, 5 days/week). Group exercise participants were provided with 3 supervised group exercise sessions per week for the first 26 weeks and with 2 sessions per week thereafter. Home exercise participants were instructed to complete all exercise in their home environment. After 6 months, both conditions displayed significant improvements in exercise participation, fitness, eating patterns, and weight loss. At 12 months, the home-based program showed superior performance to the group condition in exercise participation and treatment adherence; at 15 months, participants in the home program demonstrated significantly greater weight losses than those in the group program. This study was supported by a Research Development Award from the University of Florida Division of Sponsored Research. We appreciate the assistance of Nicole Engel, Tanya Mickler, Jennifer Oglesby, Judy Rudman, Beth Slomine, and Paula Zuffante, who served as group leaders. Correspondence may be addressed to Michael G. Perri, Department of Clinical and Health Psychology, University of Florida, P.O. Box 100165, Gainesville, Florida, 32610-0165. Received: January 19, 1996 Revised: June 24, 1996 Accepted: August 20, 1996 In recent years, the potential contribution of exercise to the management of obesity has become increasingly apparent ( Blair, 1993 ; Bouchard, Despres, & Tremblay, 1993 ; Grilo, Brownell, & Stunkard, 1993 ; Pronk & Wing, 1994 ). Exercise produces physiological, behavioral, and psychological effects that may facilitate both weight loss and the maintenance of weight loss (for Journal of Consulting and Clinical Psychology © 1997 by the American Psychological Association April 1997 Vol. 65, No. 2, 278 -285 For personal use only--not for distribution.Page 2 of 15http://spider.apa.org/ftdocs/ccp/1997/april/ccp652278.html 10/12/2000reviews, see Bouchard et al., 1993 ; and Grilo et al., 1993 ). In addition to increasing energy expenditure ( McArdle, Katch, & Katch, 1991 ), exercise may counteract the negative impact of caloric restriction on resting metabolic rate ( Tremblay et al., 1986 ), may minimize the loss of lean body mass during dieting ( Ballor & Keesey, 1991 ), and may facilitate the release of energy from adipose tissue ( Bielenski, Schutz, & Jequier, 1985 ). In obese individuals, low to moderate levels of exercise are not accompanied by corresponding increases in appetite ( Pi-Sunyer, 1992 ), and exercise may limit a preference for dietary fat ( Wood, Terry, & Haskell, 1985 ). The potential psychological benefits of exercise include improvements in mood and self-esteem ( Pronk, Jawad, Crouse, & Rohack, 1994 ). Moreover, the completion of exercise may enhance adherence to diet-related behaviors and thereby promote weight loss ( Brownell, 1995 ). Correlational studies (e.g., Harris, French, Jeffery, McGovern, & Wing, 1994 ; Kayman, Bruvold, & Stern, 1990 ) generally indicate that weight loss is associated with increased physical activity, and most controlled trials have shown that the combination of diet plus exercise typically produces greater weight loss than diet alone ( Blair, 1993 ; Pronk & Wing, 1994 ). Thus, it is now widely accepted that exercise can play a beneficial role in the treatment of obesity ( Perri & Fuller, 1995 ; Wadden, 1993 ), and most participants in weight-loss programs are successful in initiating exercise regimens ( Grilo et al., 1993 ). However, similar to nonobese persons, the majority of weight-loss program participants fail to maintain their increased levels of physical activity ( Dishman, 1991 ; Dubbert, 1992 ; Perri et al., 1988 ), and effective methods for maintaining exercise among obese adults have yet to be determined ( Grilo et al, 1993 ). Supervised group exercise sessions (conducted at a designated location) represent the most common type of formal physical activity intervention ( King, Taylor, Haskell, & DeBusk, 1990 ). This approach offers important opportunities for group support from peers as well as guidance and reinforcing feedback from a group leader ( Dishman, 1991 ; King, 1994 ). The combination of diet plus supervised group exercise versus diet alone has resulted in greater weight losses in most (e.g., Pavlou, Krey & Steffee, 1989 ; Perri, McAdoo-McAllister, Lauer, & Yancey, 1986 ; Sikand, Kondo, Foreyt, Jones, & Gotto, 1988 ; Wing et al., 1988 ) but not all (e.g., Foreyt et al., 1993 ) obesity treatment studies. Some studies of diet plus supervised group exercise (e.g., Perri et al., 1986 ; Perri et al., 1988 ) have found high initial levels of increased physical activity followed by a significant deterioration in the maintenance of exercise over time. Thus, the short-term advantages of group exercise may be outweighed by the long-term response burden entailed in traveling to a designated location at specific times for exercise completion ( King, 1994 ). Few weight loss studies have examined alternatives to supervised group exercise. Craighead and Blum (1989) compared supervised group exercise consisting of 120 min/week of walking, jogging, and calisthenics with a behavioral contract condition wherein participants agreed to complete 90 min/week of any specific exercise. Craighead and Blum (1989) found that the supervised group exercise resulted in greater weight losses at a 12-month follow-up. However, the study was limited by a lack of control over the type and amount of exercise prescribed in each condition and by the absence of exercise adherence data. Supervised home-based exercise may represent a viable alternative to group programs.