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Updated: Mar 30, 2026
In Vivo Protocol of Controlled Subconcussive Head Impacts for the Validation of Field Study Data
Published on: April 18, 2019
The Influence of Head Impact Threshold for Reporting Data in Contact and Collision Sports: Systematic Review and
D King1,2, P Hume3, C Gissane4
1Sports Performance Research Institute New Zealand, School of Sport and Recreation, Faculty of Health and Environmental Sciences, Auckland University of Technology, Auckland, New Zealand. dking@aut.ac.nz.
Background:
Head impacts and resulting head accelerations cause concussive injuries. There is no standard for reporting head impact data in sports to enable comparison between studies.
Objective:
The aim was to outline methods for reporting head impact acceleration data in sport and the effect of the acceleration thresholds on the number of impacts reported.
Methods:
A systematic review of accelerometer systems utilised to report head impact data in sport was conducted. The effect of using different thresholds on a set of impact data from 38 amateur senior rugby players in New Zealand over a competition season was calculated.
Results:
Of the 52 studies identified, 42% reported impacts using a >10-g threshold, where g is the acceleration of gravity. Studies reported descriptive statistics as mean ± standard deviation, median, 25th to 75th interquartile range, and 95th percentile. Application of the varied impact thresholds to the New Zealand data set resulted in 20,687 impacts of >10 g, 11,459 (45% less) impacts of >15 g, and 4024 (81% less) impacts of >30 g.
Discussion:
Linear and angular raw data were most frequently reported. Metrics combining raw data may be more useful; however, validity of the metrics has not been adequately addressed for sport. Differing data collection methods and descriptive statistics for reporting head impacts in sports limit inter-study comparisons. Consensus on data analysis methods for sports impact assessment is needed, including thresholds. Based on the available data, the 10-g threshold is the most commonly reported impact threshold and should be reported as the median with 25th and 75th interquartile ranges as the data are non-normally distributed. Validation studies are required to determine the best threshold and metrics for impact acceleration data collection in sport.
Conclusion:
Until in-field validation studies are completed, it is recommended that head impact data should be reported as median and interquartile ranges using the 10-g impact threshold.
