Written informed consent was obtained from parents or guardians prior to participation. The Ethical Committee of Lund University approved the study. A questionnaire was used to evaluate lifestyle factors such as school transportation, selleck screening library diseases and weekly duration of organised physical activity. The question on school transportation was asked yearly and included information as regard school transportation during winter and summer seasons. There were three possible answers: walking, cycling or going by car or bus. If the children changed their mode of transportation repeatedly or used different kinds of transportation during different seasons they were excluded. As 6 girls and 5 boys did not answer the question on mode of school transportation or used several modes of transportation, only 97 girls and 133 boys were included in this study.

Sixty girls, of which 30 were registered in the intervention group and 30 in the control group, and 75 boys, of which 34 were registered in the intervention group and 41 in the control group, walked or cycled to school. Thirty-seven girls, of whom 18 were registered in the intervention group and 19 in the control group, and 58 boys, of whom 43 were registered in the intervention group and 15 in the control group, commuted to school by car or bus. Subjective estimated level of physical activity was calculated as the sum of the duration of physical education at school and the duration of organised leisure time physical activity. The mean values of the duration of physical activity during summer and winter seasons were used.

Tanner staging [14] was used by the research nurse to assess the maturity status of the children both at baseline and at follow-up. All children remained in Tanner stage 1 during the entire study period. Body weight was measured with an electric scale to the nearest 0.1 kg and height by a wall mounted height measure to the nearest 0.5 cm. BMI was calculated as weight/height2 (kg/m2). Total body, arms and legs lean tissue mass (kg) and fat mass (kg) were measured by dual-energy X-ray absorptiometry (DXA, DPX-L version 1.3z, Lunar?, Madison, WI). The precision, evaluated by duplicate measurements in 13 healthy children, was 3.7% for total body fat mass and 1.5% for total body lean tissue mass. Concentric isokinetic knee extension and flexion peak torque was tested at an angular velocity of 60 and 180��/sec using a computerised dynamometer, (Biodex System 3?).

The knee was positioned at 90�� of flexion and went through a 75�� range of motion, stopping at 15�� of flexion. Peak torque (Nm) at both 60 and 180��/sec for extension (PTEx60; PTEx180) and flexion (PTFl60; PTFl180) were expressed as Nm/kg. The intra-individual test variability, evaluated as the coefficient of variation Entinostat for repeated measurements in 21 children, was 6.6% for PTEx60, 12.1% for PTFl60, 12.3% for PTEx180, and 9.1% for PTFl180.