Turning to the barriers which hamper people’s exercise behaviour, Dishman (2001)
identified a number of demographic and psychological impediments to the initiation of
physical activity. These barriers include demographic factors such as habitual smoking,
obesity, lower socioeconomic status and poor education as well as personal issues like
medical problems, insufficient motivation and an apparent lack of time. Curiously, this
“lack of time” explanation for physical inactivity has been challenged by research which
shows that even in environments (e.g., prisons) where time-constraints are minimal,
people’s exercise behaviour is not much different from that in the general population
(Morgan, 1977). Although the descriptive approach has been helpful in identifying
barriers to exercise initiation and in providing baseline data for public health initiatives, it
suffers from the limitation that we referred to in the previous section—its atheoretical
nature (Biddle and Nigg, 2000). In other words, it does not explain the psychological
processes (e.g., attitudes, intentions) that determine people’s level of involvement in
habitual physical activity. Fortunately, several theories have emerged in exercise
psychology to fill this gap. These theories are borrowed mainly from models of social
cognition but have been modified for use in exercise settings. Although they differ from
each other in significant ways, these theories share a common assumption that people are
rational and goal-directed in their pursuit of physical activity.
Theories of exercise behaviourAlthough many theories of exercise behaviour have been developed in recent years (for
reviews, see Buckworth and Dishman, 2002; Carron, Hausenblas and Estabrooks, 2003;
Culos-Reed, Gyurcsik and Brawley, 2001; and Marcus, Bock, Pinto, Napolitano and
Clark, 2002), space limitations prevent us from examining any but the most popular ones
in this chapter. Of these theories, three deserve special consideration. These approaches
are the theories of “reasoned action” and “planned behaviour” and the “transtheoretical
model” of behaviour change.
Although these approaches have certain similarities (e.g., in assuming that people’s
intentions predict their behaviour; Ogden, 2000), they differ in at least one important
respect. Specifically, whereas the theories of reasoned action and planned behaviour are
largely static in attempting to predict exercise behaviour, the transtheoretical model of
change is a dynamic model which assumes that people move in a spiral fashion through a
sequence of qualitatively different stages on their journey from inactivity to activity.
Furthermore, this latter approach assumes that at any point in this cycle, people can fall
back to an earlier stage—as if they were playing an exercise version of the game of
“snakes and ladders”. Let us now examine these three theories of exercise behaviour in
more detail.
Does a healthy body always lead to a healthy mind? Exploring exercise psychology 231