Sport And Exercise Psychology: A Critical Introduction

Juvenal). But lest we accept this conclusion prematurely, it is important to evaluate the
quality of the evidence on which it is based.

Evaluation of research on the benefits of physical activity

Now that we have identified the main research findings on the health benefits of regular
physical activity, we need to take a step back in order to evaluate the quality of research
evidence in this field. This critical appraisal is necessary because it goes to the heart of
any claim that habitual exercise is good for us. In a nutshell, researchers and practitioners
in the field of exercise psychology must be satisfied that the alleged health benefits
described above are caused solely by physical activity rather than by other factors. These
factors could include intervening variables such as people’s expectations about the likely
effects of exercise interventions, contextual factors like the environment in which the
physical activity occurs (see Bodin and Hartig, 2003) and a host of methodological flaws
such as researchers’ failure to use non-exercise control groups or to match people for
their fitness histories. To prevent inaccurate interpretation of research in this field,
therefore, at least five conceptual and methodological issues concerning the benefits of
physical activity can be specified as follows.
To begin with, consider the familiar direction of causality issue. In simple terms, are
such experiences as “feeling well” and “thinking clearly” the cause or the consequence of
people’s involvement in regular exercise? As with all causal issues in psychology, this is
a complex issue which can be addressed only by the use of controlled experimental
research designs. Ideally, such designs would involve a chronic exercise programme in
which sedentary participants are assigned randomly to physical activity or control
conditions. Unfortunately, the prevalence of correlational research designs in this field
makes it difficult to test causal hypotheses about the relationship between exercise and
mental processes. In any case, there is a vast array of intervening variables in this
relationship. For example, research indicates that the motives of exercisers and the
behaviour of their instructors may affect health experiences. Thus Grant (2000) suggested
that the physical activity tends to have its strongest effect on people’s mood and sense of
well-being when exercisers have a task orientation (see Chapter 2), in which they focus
on mastering the exercise activity for its own sake rather than in an effort to exercise
better or faster than others in the group (thereby reflecting an ego orientation). In
structured exercise situations, the behaviour of the instructor could modify the health
benefits yielded by the activity undertaken. For example, Turner, Rejeski and Brawley
(1997) explored the effect of an exercise teacher’s leadership style on the affective states
of exercise participants. Briefly, these authors asked a sample of female university
students to complete a scale designed to measure “exercise-induced” feeling states (see
Gauvin and Rejeski, 1993). Then, the women were assigned randomly either to an
“enriched” or to a “bland” exercise instruction condition. Finally, they were tested on the
inventory once again. Results revealed that participants in the enriched condition scored
significantly higher than did those in the bland condition on the affective dimensions of
“revitalisation” and “positive engagement”. This finding was interpreted as showing that
the social environment created by an activity instructor may influence the benefits
produced by the exercise activity itself. Unfortunately, many exercise psychology
researchers have failed either to eliminate or to measure the effects of such intervening

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