Table 1 Set of candidate prognostic factors (with corresponding number of parameters) for model development

Systematic review/clinical reasoning

Age

Years and days

1

Date of birth

Continuous

N/A

Frequency of previous IMIs within 3 years prior to PHE

Count

1

Medical records

Discrete (treated as continuous)

N/A

Most recent previous IMI within 3 years prior to baseline PHE

Never (ref); < 6 months; 6–12 months; > 12 months

3

Medical records

Categorical

N/A

Data quality/clinical reasoning

CMJ peak power

Watts

1

CMJ using force plates

Continuous

Test-retest ICC = 0.92–0.98 [28]

PROM hip joint internal rotation difference*

Degrees

1

Supine ROM test using digital inclinometer

Continuous

Intra-rater ICC = 0.90 [29]

PROM hip joint external rotation difference*

Degrees

1

Supine ROM test using digital inclinometer

Continuous

Intra-rater ICC = 0.90 [29]

Hip flexor muscle length difference*

Degrees

1

Thomas test using digital inclinometer

Continuous

Inter-rater ICC = 0.89 [30]

Hamstring muscle length/neural mobility difference*

Degrees

1

SLR using digital inclinometer

Continuous

Intra-rater ICC = 0.95–0.98 [31]; inter-rater ICC = 0.80–0.97 [32]

Calf muscle length difference*

Degrees

1

WBL using digital inclinometer

Continuous

Inter-rater ICC = 0.80–0.95 [33, 34]; intra-rater ICC = 0.88 [34]

BMI

kg/m²

1

Composite height (cm) and weight (kg)

Continuous

N/A