Table 1.

Characteristics of participants at Time 1 and Time 2 (N = 187) and p-values for the outcome variables

Variable	Time 1 (T1)				Time 2 (T2)				p-value
	N	%	M	SD	N	%	M	SD
Personal characteristics
Sex	187
Boys	149	79.7
Girls	38	20.3
Age (years)	186		14.41	1.47
Youth development
SDQ (total)	170		10.89	5.00	171		11.18	4.88	.67
Pro-social behaviour	185		7.42	1.90	184		7.36	1.89	.55
School performance	187		3.30	0.82	187		3.29	0.83	.84
Subjective health	187		3.44	1.05	187		3.43	0.92	.76
Well-being	187		3.40	1.00	187		3.35	0.86	.59
Assets
Self-regulation skills
Planning	147		2.42	0.58	141		2.46	0.62	.71
Monitoring	149		2.54	0.57	139		2.50	0.64	.48
Effort	149		2.69	0.51	137		2.67	0.51	.34
Sense of coherence
Sense of coherence	178		34.09	7.82	180		33.52	7.77	.29
Sports participation
Frequency of sport (average week)	186				186
Did not sport	50	26.9			54	29.0
1 or 2 times a week	70	37.6			63	33.8
3 or more times a week	66	35.5			69	37.1
Duration of sport (average per activity)	185				185
Did not sport	50	27.0			55	29.7
< ½ an hour	7	3.8			9	4.9
Between ½ - 1 h	17	9.2			13	7.0
Between 1 and 2 h	93	50.3			95	51.4
Between 2 and 3 h	10	5.4			9	4.9
Longer than 3 h	8	4.3			4	2.2
Membership of sports/fitness club	186				185
No	84	45.2			97	52.4
Yes	102	54.8			88	47.6

SDQ total Strengths and Difficulties. Scale range: SDQ total (0–40); pro-social behaviour (0–10); school performance, subjective health, and well-being (1–5); planning, monitoring, and effort (1–4); reflection (1–5); sense of coherence (0–52)