Wearable Inertial Measurement Unit to Accelerometer-Based Training Monotony and Strain during a Soccer Season: A within-Group Study for Starters and Non-Starters

Abstract

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.

Win, Draw, or Lose? Global Positioning System-Based Variables’ Effect on the Match Outcome: A Full-Season Study on an Iranian Professional Soccer Team

“…The decline in the second half could be a result of a more intense first half, however, a lack of a direct causal relationship between fatigue to a single factor makes it difficult to draw direct conclusions [ 43 , 44 , 45 ]. Additional factors such as players engaging in pacing strategies to self-regulate throughout the match to avoid fatigue, although there is limited data to explain this theory [ 43 , 44 , 46 ]. Moreover, the prior knowledge about the first half, opponents and their style of play, and because there is still another half to play may create a higher effort regulation capability, that led players to increase their exercise economy by improving positional relationships, which means that players may have decreased their workload to focus on more ball location, and the space available to play as suggested by Ferraz et al [ 47 ].…”

Acute and Chronic Workload Ratios of Perceived Exertion, Global Positioning System, and Running-Based Variables Between Starters and Non-starters: A Male Professional Team Study

“…Furthermore, the analysis of playing status emerged through other variables such as monotony, strain, or accumulated load. Even so, it has been showed a tendency of higher values for starters compared to non-starters ( Nobari et al, 2020 , 2021d , f ).…”

Variations of High-Intensity GPS Derived Measures between Playing Status during a Full Soccer Season in a Professional Male Team

“…Moreover, recent research analysed the differences between playing statuses based on several metrics, such as monotony, strain, and accumulated intensity of specific periods of the season; they all found higher values in starters than non-starters [16][17][18]. However, one study did not confirm such differences between playing statuses, finding values for starters and non-starters across the season [13].…”