The Value of Preseason Screening for Injury Prediction: The Development and Internal Validation of a Multivariable Prognostic Model to Predict Indirect Muscle Injury Risk in Elite Football (Soccer) Players

Tom Hughes,Jamie C Sergeant,Michael J Callaghan,Richard D Riley

doi:10.1186/s40798-020-00249-8

Abstract

BackgroundIn elite football (soccer), periodic health examination (PHE) could provide prognostic factors to predict injury risk.ObjectiveTo develop and internally validate a prognostic model to predict individualised indirect (non-contact) muscle injury (IMI) risk during a season in elite footballers, only using PHE-derived candidate prognostic factors.MethodsRoutinely collected preseason PHE and injury data were used from 152 players over 5 seasons (1st July 2013 to 19th May 2018). Ten candidate prognostic factors (12 parameters) were included in model development. Multiple imputation was used to handle missing values. The outcome was any time-loss, index indirect muscle injury (I-IMI) affecting the lower extremity. A full logistic regression model was fitted, and a parsimonious model developed using backward-selection to remove factors that exceeded a threshold that was equivalent to Akaike’s Information Criterion (alpha 0.157). Predictive performance was assessed through calibration, discrimination and decision-curve analysis, averaged across all imputed datasets. The model was internally validated using bootstrapping and adjusted for overfitting.ResultsDuring 317 participant-seasons, 138 I-IMIs were recorded. The parsimonious model included only age and frequency of previous IMIs; apparent calibration was perfect, but discrimination was modest (C-index = 0.641, 95% confidence interval (CI) = 0.580 to 0.703), with clinical utility evident between risk thresholds of 37–71%. After validation and overfitting adjustment, performance deteriorated (C-index = 0.589 (95% CI = 0.528 to 0.651); calibration-in-the-large = − 0.009 (95% CI = − 0.239 to 0.239); calibration slope = 0.718 (95% CI = 0.275 to 1.161)).ConclusionThe selected PHE data were insufficient prognostic factors from which to develop a useful model for predicting IMI risk in elite footballers. Further research should prioritise identifying novel prognostic factors to improve future risk prediction models in this field.Trial registrationNCT03782389

Highlights

In elite football, periodic health examination (PHE) could provide prognostic factors to predict injury risk
The selected PHE data were insufficient prognostic factors from which to develop a useful model for predicting indirect (non-contact) muscle injury (IMI) risk in elite footballers
This meant they were unavailable for full training or to play matches at that time. These players had commenced football specific, field-based rehabilitation around this time, so had similar exposure to training activities as the uninjured players. These players were included in the cohort because it was reasonable to assume that they could be considered at risk of an indirect muscle injury (I-IMI) event even during their rehabilitation activities

Summary

Introduction

In elite football (soccer), periodic health examination (PHE) could provide prognostic factors to predict injury risk. PHE has a rehabilitation and performance monitoring function [12] and is used to detect musculoskeletal or medical conditions that may be dangerous or performance limiting [13]. Another perceived role of PHE is to recognise and manage factors that may increase, or predict, an athlete’s future injury risk [10], this function is currently unsubstantiated [13]

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