Book reviews

Rotter, Ekkehart, Abendland und Saratenen: das okxidentale Araberbild und seine Entetehung im Frühmittelalter. Berlin and New York: Walter de Gruyter, 1986. (Studien zur Sprache, Geschichte und Kultur des Islamischen Orients, neue Folge, Band 11) 290+xiipp. 2 genealogical charts; Sketch map; sketch; DM 158.

Irwin, Robert. The Middle East in the Middle Ages: The Early Mamlük Sultanate 1250–1382. Carbondale and Edwardsville: Southern Illinois University Press, 1986. 180 pp.: US $26.95.

Kobbervig, Karl I. El Libro de las Suertes: tratado de adivinación por el Juego de azar. Estudio, edición y glosario. Madrid: Gredos, 1987 (Colección de Literatura Española Aljamiado‐Morisca, 7), 227pp., including a full‐page facsimiles from the MSS.

Cutler, Allan Harris and Cutler, Helen Elmquist. The Jaw as Ally of the Muslim: Medieval Roots of Anti‐Semitism. Notre Dame, Indiana: University of Notre Dame Press, 1986, x + 577 pp., Indices; bibliography; US $50.00

Parker, S. Thomas. Romans and Saracens: A History of the Arabian Frontier. (American Schools of Oriental Research 1986. Dissertation Series, 6) Winona Lake, Indiana: Eisenbrauns,1987. xiii + 247pp.: US $25.00.

De Montêquin, François‐Auguste (compilar). Muslim Architecture of the Ibrian Peninsula: Eastern and Wastern Sources for Hispano‐Islamic Building Arts. West Cornwall. Locust Hill Press, 1987, xv + 241 pp.; US $30.00.     

Tracking of physical activity in adolescence

The present analysis aimed to describe the degree of tracking of physical activity over an 8-year follow-up period among a cohort of 557 adolescents in western Norway (13 years of age at baseline). Frequency and time spent in leisure-time physical activity were assessed at ages 13, 14, 15, 16, 18, 19 and 21 years through self-report questionnaires. The cross-sectional results indicated that proportions of adolescents who were physically active declined from 13 to 19 years of age and increased slightly from 19 to 21 years of age. Longitudinally, various measures indicated a weak degree of tracking of physical activity (Pearson's r was .22 for boys and. 18 for girls across the 8-year period). The least active persons during early adolescence were those least likely to change during their teenage years. In sum, the findings indicated a weak tendency of tracking of physical activity through adolescence.