Supplementary Table 1. Mean, 95% confidence intervals (95%Cl) and standard deviation (SD) of tackle proficiency scores for each category. Data reported at Arbitrary Units.

Tackle Proficiency Criteria	Low scoring tackles			Medium scoring tackles			High scoring tackles
	Mean	95%Cl	SD	Mean	95%Cl	SD	Mean	95%Cl	SD
Low body position (dipping i.e., upright-to-low)	0.7	0.6 – 0.9	0.5	0.8	0.7 – 0.8	0.4	0.9	0.9-1.0*	0.2
Straight back, centre of gravity ahead of base of support	0.9	0.7 – 1.0	0.4	0.9	0.9 – 1.0	0.2	0.9	0.9 – 1.0	0.2
'Boxer stance' (elbows bent, hands forward and open)	0.04	0 – 0.1	0.2	0.4	0.3 – 0.5*	0.5	0.7	0.6 – 0.8*	0.5
Head up and forward with eyes open	1.0	0	0	1.0	0	0	1.0		0
Shortening steps	0	0	0	0.1	0.07 – 0.2*	0.3	0.4	0.3-0.4*	0.5
Pre-contact total	2.6	2.4 – 2.8	0.5	3.2	3.1 – 3.4*	0.7	3.9	3.8 – 4.1*	0.7
Explode with leading leg into contact	0.2	0.03 – 0.4	0.4	0.5	0.4 – 0.6	0.5	0.8	0.8 – 0.9*	0.4
Contact target with shoulder within region below shoulders and above hips	0.8	0.6 – 0.9	0.4	0.9	0.9 – 1	0.2	1.0*	0	0.1
Place head on correct side of ball-carrier	1.0	0	0	1.0	0	0	1.0	0	0
Contact total	2	1.8 – 2.2	0.5	2.5	2.4 – 2.6*	0.5	2.8	2.7 – 2.9*	0.4
Drive through contact with legs and shoulder	0.04	0 – 0.1	0.2	0.2	0.1 – 0.3	0.4	0.6	0.5 – 0.7*	0.5
Arm usage (wrap i.e., hit-and-stick)	0.04	0 – 0.1	0.2	0.3	0.2 – 0.4*	0.4	0.4	0.4 – 0.5*	0.5
Jackle	0.1	0 – 0.3	0.3	0.6	0.5 – 0.7*	0.5	0.8	0.7 – 0.9*	0.4
Post contact total	0.2	0.03 – 0.4	0.4	1.04	0.9 – 1.2	0.8	1.7	1.7 – 2.0*	0.7
Total Score	4.8	4.6 – 4.9*	0.4	6.7	6.6 – 6.8*	0.5	8.6	8.4 – 8.7*	0.8
Percentage	44 %			61 %			78 %