Table 3.

Change in average alpha angle with age by cohort.

		Average alpha angle (± SD)			Univariate regression
		Baseline	Follow-up	Mean change	Coefficient	95% CI	P value
Male footballers
Age at baseline (years)	9–10	48.31 (± 4.04)	62.62 (± 10.47)	14.66 (± 9.61)	9.73	7.03 to 12.42	< 0.001
	11–12	50.37 (± 4.95)	65.31 (± 9.13)	15.03 (± 7.36)	10.09	7.74 to 12.45	< 0.001
	13–14	61.41 (± 8.801	66.06 (± 8.79)	8.17 (± 4.46)	3.24	1.07 to 5.41	0.003
	15–16	65.89 (± 12.55)	70.33 (± 12.55)	4.97 (± 2.34)	0.04	−1.42 to 1.49	0.963
	17–18	66.43 (± 15.57)	58.27 (± 7.49)	4.93 (± 1.16)	–	–	–
Average		55.28 (± 11.01)	64.52 (± 10.19)	12.44 (± 8.45)
Male controls
Age at baseline (years)	9–10	47.76 (± 3.00)	54.93 (± 5.28)	7.18 (± 5.88)	2.81	−0.40 to 6.02	0.047
	11–12	50.43 (± 4.82)	60.92 (± 8.34)	11.21 (± 6.84)	6.84	3.16 to 10.52	< 0.001
	13–14	56.75 (± 5.11)	62.10 (± 5.70)	6.08 (± 3.25)	1.70	−1.37 to 4.78	0.278
	15–16	60.29 (± 9.26)	65.81 (± 11.40)	3.67 (± 3.18)	−0.71	−3.41 to 2.00	0.609
	17–18	58.13 (± 2.80)	61.31 (± 6.34)	4.37 (± 2.29)	–	–	–
Average		53.40 (± 7.73)	60.13 (± 8.84)	7.32 (± 5.97)
Female controls
Age at baseline (years)	9–10	47.86 (± 3.83)	55.32 (± 4.97)	7.68 (± 5.00)	5.76	−1.59 to 1.92	< 0.001
	11–12	52.08 (± 5.42)	58.78 (± 5.59)	5.39 (± 3.42)	3.46	−1.84 to 1.83	0.007
	13–14	50.44 (± 4.76)	53.42 (± 4.80)	1.09 (± 2.16)	−0.00	0.94 to 5.99	1.000
	15–16	50.73 (± 7.01)	53.02 (± 7.39)	2.09 (± 1.95)	0.17	3.14 to 8.38	0.853
	17–18	54.34 (± 7.33)	58.18 (± 6.60)	1.93 (± 2.35)	–	–	–
Average		50.63 (± 6.06)	55.12 (± 6.13)	4.05 (± 4.13)