title: Acute affective responses to prescribed and self-selected exercise sessions in adolescent girls: an observational study.
abstract: BACKGROUND
  Positive affective responses can lead to improved adherence to exercise. This study sought to examine the affective responses and exercise intensity of self-selected exercise in adolescent girls.
  
  
  METHODS
  An observational study where twenty seven females (Age M = 14.6 ± 0.8 years) completed three 20-minute exercise sessions (2 self-selected and 1 prescribed intensity) and a graded exercise test. The intensity of the prescribed session was matched to the first self-selected session. Intensity, affective responses and ratings of perceived exertion were recorded throughout the sessions and differences examined. Repeated measures ANOVAs were conducted to examine differences.
  
  
  RESULTS
  There were no significant differences in intensity between the prescribed and self-selected sessions, but affective responses were significantly more positive (p < .01) during the self-selected session. Ratings of perceived exertion were significantly lower (p < .01) during the self-selected session than the prescribed session. On average participants worked at 72% [Formula: see text] peak; well within the intensity recommended by the American College of Sports Medicine.
  
  
  CONCLUSIONS
  Even though the intensity did not differ between the self-selected and prescribed sessions, there was a significant impact on affective responses, with more positive affective responses being elicited in the self-selected session. This highlights the importance of autonomy and self-paced exercise for affective responses and may have potential long-term implications for adherence.
authors.affiliation: General and Adolescent Paediatrics Unit, Population, Policy and Practice, UCL Institute of Child Health, 30 Guilford Street, London WC1N 1EH, UK ; Sport and Health Sciences, College of Life and Environmental Sciences, University of Exeter, Exeter, UK.
authors.forename: Charlotte C
authors.initials: CC
authors.lastname: Hamlyn-Williams
authors.affiliation: Sport and Health Sciences, College of Life and Environmental Sciences, University of Exeter, Exeter, UK.
authors.forename: Paul
authors.initials: P
authors.lastname: Freeman
authors.affiliation: School of Health Sciences, Sansom Institute for Health Research, University of South Australia, Adelaide, SA, Australia.
authors.forename: Gaynor
authors.initials: G
authors.lastname: Parfitt
keywords: Adolescent exercise; Affect; Autonomy; Exercise psychology; Physical activity