Every week for many people the enthusiasm to exercise fluctuate and these changes predict if they will be physically active, assert researchers.
In an effort to understand how the motivation to exercise is linked to behaviour, the researchers at Penn State examined college students' intentions to be physically active as well as their actual activity levels.
"Many of us set New Year's resolutions to be more physically active, and we expect these resolutions to be stable throughout the year," said David Conroy, professor of kinesiology.
Conroy and colleagues recruited 33 college students and assessed over a ten-week period both the students' weekly intentions to be physically active and their activity levels.
During each of the ten weeks, participants were instructed to log on to a website and to rate their intentions to perform physical activity for the week ahead. To assess physical activity, participants were instructed to wear pedometers each day for the first four weeks.
The team found that for many of the participants, the motivation to exercise fluctuated on a weekly basis, and these fluctuations were linked to their behaviour.
"Our motivation to be physically active changes on a weekly basis because we have so many demands on our time," said Conroy.
"Maybe one week we're sick or we have a work deadline-or, in the case of students, an upcoming exam. But these lapses in motivation really seem to be destructive. Our results suggest that people with consistently strong intentions to exercise have the best chance of actually following through on their intentions, while people with the greatest fluctuations in their motivation have the hardest time using that motivation to regulate their behaviour," he explained.
Conroy added that consistency of intentions is not the only thing that matters in predicting whether or not a person will be active. It also matters if it is a weekday or the weekend.
"We saw that people who consistently reported stronger intentions to be active were more active during the week, but then on weekends the pattern flipped for them. If a person was really motivated during the week, then he or she crashed on the weekend," said Conroy.
The results have been published in the current issue of the Journal of Sport and Exercise Psychology.