Challenges in improving fitness: results of a community-based, randomized, controlled lifestyle change intervention.
OBJECTIVE
This study tested the efficacy of an 8-week culturally targeted nutrition and physical activity intervention on body composition.


METHODS
A randomized, attention-controlled, two-group trial was conducted in a blackowned commercial gym with a sample of 366 predominantly healthy, obese African American women. A free 1-year membership to the study site gym was provided to participants in both groups. Data were collected at baseline, 2, 6, and 12 months.


RESULTS
Sample retention at 1 year was 71%. Between-group longitudinal analysis including only participants with complete data revealed a trend toward weight stability in the intervention group at 2 months compared with controls (+0.05 kg/m(2), p = 0.75; +0.32 kg/m(2), p = 0.08, respectively), disappearing at 12 months (+1.37 kg/m(2), p = 0.0001; +1.02 kg/m(2), p = 0.001, respectively). Within-group analysis demonstrated that intervention and control participants' fitness (1-mile run-walk) improved by 1.9 minutes (p = 0.0001) and 2.3 minutes (p = 0.0001), respectively, at 12 months. Mixed model regression analyses demonstrated a significant main effect of the intervention on fitness (p = 0.0185) and a marginally significant effect on body mass index (BMI) (p = 0.057), at 2 months, disappearing by 6 months. By 12 months, however, the controls exhibited a significant advantage in waist circumference stability compared with intervention participants (+1.1 cm, p = 0.2763; +2.1 cm, p = 0.0002, respectively).


CONCLUSIONS
The intervention produced modest short-term improvements in body composition, but the economic incentive of a free 1-year gym membership provided to all participants was a more potent intervention than the education and social support intervention tested. However, longer-term fitness enhancement remains elusive and demands research and policy attention. These findings have policy implications in that employer-/insurer-subsidized gym memberships may require interventions targeting other levels of change (e.g., physical or social/environmental) to foster sustainable fitness improvements.
Yancey
Antronette K
AK
Department of Health Services, UCLA School of Public Health, Los Angeles, California 90095, USA. ayancey@ucla.edu
McCarthy
William J
WJ
Harrison
Gail G
GG
Wong
Weng Kee
WK
Siegel
Judith M
JM
Leslie
Joanne
J
D000328:Adult; D001741:Black or African American / Q000706:statistics & numerical data*; D000368:Aged; D015444:Exercise / Q000523:psychology*; D005260:Female; D015438:Health Behavior; D006293:Health Promotion / Q000379:methods*; D006801:Humans; D008019:Life Style; D008875:Middle Aged; D009765:Obesity / Q000517:prevention & control* / Q000523:psychology; D012649:Self Concept; D012959:Socioeconomic Factors; D016896:Treatment Outcome; D016387:Women's Health