Quantifying technical actions in professional soccer using foot-mounted inertial measurement units

ABSTRACT

Objectives

This study aimed to (i) establish the concurrent validity and intra-unit reliability of a foot-mounted inertial measurement unit for monitoring soccer technical actions, (ii) quantify the within-microcycle inter-positional differences in the technical actions of professional soccer training, and (iii) determine the influence of drill category on the technical actions of professional soccer training.

Methods

Twenty-one professional soccer players’ technical performance data (ball touches, releases, ball touches per minute, releases per minute), collected during training sessions throughout twenty-four weekly microcycles, were analysed using general linear modelling.

Results

The inertial measurement unit exhibited good concurrent validity (P_A = 95.1% – 100.0%) and intra-unit reliability (P_A = 95.9% – 96.9%, CV = 1.4% – 2.9%) when compared with retrospective video analyses. The most ball touches ($\bar{\mathrm{X}}$ = 218.0) and releases ($\bar{\mathrm{X}}$ = 110.8) were observed on MD – 1, with MD – 5 eliciting the highest frequency of ball touches ($\bar{\mathrm{X}}$ = 3.8) and releases ($\bar{\mathrm{X}}$ = 1.7) per minute. Central midfielders performed the most ball touches ($\bar{\mathrm{X}}$ = 221.9), releases ($\bar{\mathrm{X}}$ = 108.3), ball touches per minute ($\bar{\mathrm{X}}$ = 3.4) and releases per minute ($\bar{\mathrm{X}}$ = 1.6). Small-sided games evoked more ball touches ($\bar{\mathrm{X}}$^diff = 1.5) and releases per minute ($\bar{\mathrm{X}}$^diff = 0.1) than previously reported in match-play. The fewest ball touches ($\bar{\mathrm{X}}$ = 1.2) and releases per minute ($\bar{\mathrm{X}}$ = 0.5) were observed during tactical drills.

Conclusion

The results of this study provide a novel understanding of the within-microcycle, inter-positional and drill category differences in the technical actions performed by professional players during training.

KEYWORDS:

• Professional soccer training
• technical actions
• player monitoring
• microcycle
• microtechnology

Acknowledgements

The authors would like to thank all players and coaching staff at the soccer club for their cooperation and assistance during this study.

Disclosure statement

The second author of this study is now employed by the company who provided the foot-mounted IMUs used to collect players’ technical performance data. However, throughout the data collection and writing up periods, the second author had the same affiliation as the first author and was not involved with the company in any way. Despite this, and to remove the potential for bias, the second author was not involved in any statistical analyses or data interpretation conducted during the investigation.

Additional information

Funding

No funding is associated with this study.