Normalizing Acceleration and Power in Elite Soccer With Acceleration-Speed Profiles: A Case Study of Game Segment, Position, and Goal Differential.

Purpose: Acceleration-speed (AS) profiling provides a novel way to quantify soccer players' maximum running ability without requiring dedicated sprint tests. This study explored how normalizing player effort with AS profiles could reveal unique patterns of changes in effort compared with nonnormalized absolute values during distinct goal differential conditions throughout matches and across positions.

Methods: AS profiles were developed from global navigation satellite system sensor data from 3 years of match play from a women's national soccer team. Acceleration and power data were then grouped into low, moderate, high, and very high speed domains using either nonnormalized maximum values or normalized values based on individualized AS profiles. Separate linear mixed model analyses were carried out for normalized and nonnormalized data.

Results: The analysis revealed that when examining changes in acceleration effort based on goal differential, both normalized and nonnormalized values showed a general increase in effort when either in a draw, or winning in the first half, and a general trend in sustained effort when losing in the first half or losing/drawn throughout the match. Furthermore, differences were mostly displayed at high to very high running-speed domains for normalized and moderate- to low-speed zones for nonnormalized metrics.

Conclusions: These findings highlight the value of using individual AS and power profiles to normalize effort to facilitate investigation of player- and position-specific differences and reveal important positional behaviors displayed when in draw, losing, or winning states from first to second halves.