Wearable inertial measurement unit to accelerometer-based training monotony and strain during a soccer season: A within-group study for starters and non-starters

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Nobari H., Söğüt M., Oliveira R., Pérez-Gómez J., Suzuki K., Zouhal H.

International Journal of Environmental Research and Public Health, vol.18, no.15, 2021 (SCI-Expanded) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 18 Issue: 15
  • Publication Date: 2021
  • Doi Number: 10.3390/ijerph18158007
  • Journal Name: International Journal of Environmental Research and Public Health
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Social Sciences Citation Index (SSCI), Scopus, Aqualine, Aquatic Science & Fisheries Abstracts (ASFA), CAB Abstracts, EMBASE, Food Science & Technology Abstracts, Geobase, MEDLINE, Pollution Abstracts, Veterinary Science Database, Directory of Open Access Journals
  • Keywords: football, external training load, WIMU, GPS, acceleration, deceleration, LOAD, ACCELERATION, PRESEASON, PLAYERS
  • Middle East Technical University Affiliated: Yes


The purpose of this study was to analyze the intragroup differences in weekly training monotony (TM) and training strain (TS) between starter and non-starter male professional soccer players at accelerometry-based variables throughout the periods of a season. TM and TS of different accelerations and decelerations zones for twenty-one players were followed for forty-eight weeks. Regardless of group, players obtained the highest mean TM (starters = 3.3 ± 0.6, non-starters = 2.2 ± 1.1, in arbitrary unit, AU) and TS (starters = 1288.9 ± 265.2, non-starters = 765.4 ± 547.5, AU) scores in the pre-season for accelerations at Zone 1 (<2 m/s2). The results also indicated that both groups exhibited similar TM and TS scores in accelerations at Zones 2 (2 to 4 m/s2) and 3 (>4 m/s2) across the entire season. While the starters showed the highest TM and TS scores at deceleration Zone 1 (<−2 m/s2) in the end-season, the non-starters exhibited the highest scores at the deceleration Zone 1 in pre-season. It seems that in pre-season, coaches applied higher levels of training with greater emphasis on deceleration for non-starters. This tendency was reduced over time for non-starters, while starters presented higher values of deceleration Zone 1. These results highlight the variations in TM and TS across the different periods of a full season according to match starting status among professional soccer players, and the results suggest that non-starter players should receive higher levels of load to compensate for non-participation in matches throughout a soccer season.