Studies addressing children's perceptions of exercise effort have appeared steadily in the scientific literature over the last 20 years, though they have been relatively sparse in number. With little or no regard for their suitability, researchers initially applied to children the methods and applications of the rating of perceived exertion (RPE) notion established amongst adults. Whilst some success was claimed, findings were inconclusive, possibly because of the use of an inappropriate measurement scale. More recently, the development of the child-specific Children's Effort Rating Table (CERT) has advanced research in this domain and helped to focus attention on the numerous problems of applying this psychophysical concept to such immature subjects. Accordingly, the scope for further research in this discipline is now far broader than ever before.