Exercise and psychosocial health

The rapidly expanding literature on exercise and health has always included psychological and psychosocial health, albeit initially at a rather anecdotal level of describing the ''feel good effect'' participants often report after exercise (Biddle & Mutrie, 1991). In reviewing the literature, exercise will not be strictly delimited. Habitual physical activity, exercise, aerobic fitness training, and sport will all be included where appropriate. Psychosocial health is also broadly defined to include psychological and social-psychological outcomes. However, there is no accepted definition in the field, although mental health usually includes positive characteristics, such as high self-esteem and positive mood (Mutrie & Biddle, 1995; Stephens, 1988), as well as reduced levels of negative affect, such as anxiety and depression (Martinsen & Stephens, 1994). More recently, as far as exercise is concerned, other aspects have also been studied (see Mutrie & Biddle, 1995), such as cognitive functioning and stress reactivity, as well as the potential negative psychological effects of exercise (e.g., dependence). In the meta-analyses referred to below trends are quantified across studies through the calculation of an effect size (ES) which represents the meaningfulness of exercise effects. Tt is calculated as the difference between experimental (treatment) and comparison (control) group means divided by tile control group or pooled standard deviation (see Salazar, Petruzzello, Landers, Etnier, & Kubitz, 1993; Thomas sc French, 1986). For the sake of interpretation, ESs below 0.39 will be classified as small, 0.40-0.69 as moderate, and above 0.70 as large (Thomas, Salazar, & Landers, 1991).