Time-motion analysis in elite soccer players: small-sided games vs. match performance

Aim: Semi-Automatic Tracking System (SATS) and global positioning system (GPS) are used to determine players’ loads and drills during soccer activities. Small-sided games (SSGs) are utilized as skill-based conditioning drills, the workload intensity of which is a crucial feature. The study was aimed at comparing the equivalent distance (ED, i.e., distance covered while running at constant speed on flat terrain, for a given energy expenditure) determined during SSGs with average ED during official matches (EDmatch). Moreover, the interchangeability of SATS and GPS during SSGs is a crucial issue and was also assessed. Methods: Twenty-five e´lite soccer players performed a total of 1033 and 1532 observations for collective possession plays (SSG-P) and SSGs with goalkeeper (SSG-G), respectively. SSGs were evaluated by GPS (10 Hz; accelerometer: 100 Hz, 16G Tri-Axis). Each drill was normalized per meter covered in 1 min (m min-1) and area per player (m2player). In addition, thirty-nine official matches (18 observations per player) were monitored by SATS. Lastly, a typical training session with SSGs was monitored with both GPS and SATS to assess their interchangeability. Results: A small typical error of the estimate (TEE: 0.07, 95 %CI: 0.04/0.13) and a high correlation (r2 = 0.99, P\0.001) were found between SATS and GPS. A correlation (r2 = 0.79, P\0.001) between ED and m2player was found only for SSG-P. The regression- line in SSG-P crossed EDmatch at an average area of 95.8 m2player. Conclusions: A small TEE and a high correlation permitted a comparison between GPS and SATS. Due to a lower tactical and higher physical involvement than in SSG-G, ED increased with m2player and induced average EDmatch only during SSG-P. These findings may contribute to better assess workloads using SSG-P with respect to match intensity. References di Prampero PE et al (2015) Eur J Appl Physiol 115(3):451–469. Buchheit M et al (2014) J Sports Sci 32(20):1844–1857.