Table 3.

Tracking of physical characteristics, fitness and physical activity levels between age 15y and young adulthood (mean age 22.0y)

	Males			Females
	n	κ	P	n	κ	P
Weight (kg)	245	0.337	<0.0001	231	0.540	<0.0001
Height (m)	245	0.444	<0.0001	231	0.813	<0.0001
Body mass index (kgm-2)	245	0.422	<0.0001	231	0.452	<0.0001
Biceps skinfold (mm)	244	0.224	<0.0001	230	0.403	<0.0001
Triceps skinfold (mm)	244	0.292	<0.0001	230	0.287	<0.0001
Subscapular skinfold (mm)	244	0.274	<0.0001	230	0.371	<0.0001
Suprailiac skinfold (mm)	244	0.223	<0.0001	230	0.202	<0.0001
Sum of skinfolds (mm)	244	0.216	<0.0001	230	0.357	<0.0001
VO2maxa	222	0.150	<0.0001	209	0.076	0.128
Physical activity scoreb	240	0.202	<0.0001	225	0.021	0.669

^a VO₂max at age 15y was derived from the number of 20 metre shuttle run laps completed by each subject. At follow-up, VO₂max was extrapolated from the results of a cycle ergometer test (Physical Work Capacity at a heart rate of 170 bpm; PWC170).

^b Physical activity scores at age 15y were calculated according to the method of Riddoch et al (1991). At follow-up, a modification (Pereira et al, 1997) of the Baecke questionnaire was used.

κ indicates extent of tracking, and can be interpreted as follows: κ < 0.20, poor tracking; κ 0.21–0.40, fair; κ 0.41–0.60, moderate; κ 0.61–0.8, good; κ 0.81–1.0, very good (Altman, 1991).