Finally, it is also important to highlight that the acceleration values (number of actions, distance covered in meters or in % of the total, time in seconds or in % of the total) are obtained through positioning values, and not from the accelerometers contained in some of the devices commercially available today. This partly explains why the reliability and validity of acceleration measurements are dependent on acceleration and velocity, with the worst results coming from an increased movement velocity and/or acceleration magnitude. David Casamichana Gómez, Doctor in Physical Activity and Sports Science. Physical trainer in soccer. University Professor and Researcher. Expert of the Certificate in Workload Management in Football at Barça Innovation Hub – Universitas. References Buchheit M, Al Haddad H, Simpson BM, Palazzi D, Bourdon PC, Di Salvo V, and Mendez-Villaneuva A. Monitoring accelerations with GPS in football: time to slow down? Int J Sports Physiol Perform. 2014;9:442-445 Castellano, J., & Casamichana, D., (2013). Differences in the number of accelerations between small-sided games and friendly matches in soccer. Journal of Sports Science and Medicine, 12(1), 209-210. Hodgson, C., Akenhead, R., & Thomas, K. (2014). Time-motion analysis of acceleration demands of 4v4 small-sided soccer games played on different pitch sizes. Human Movement Science, 33, 25-32. Osgnach, C., Poser, S., Bernardini, R., Rinaldo, R., & di Prampero, P. E . (2010). Energy cost and metabolic power in elite soccer: a new match analysis approach. Medicine & Science in Sports & Exercise, 42, 170-178. Sonderegger K, Tschopp M, TaubeW (2016) The Challenge of Evaluating the Intensity of Short Actions in Soccer: A New Methodological Approach Using Percentage Acceleration. PLoS ONE 11(11): e0166534. doi:10.1371/journal. pone.0166534. Varley, M.C., & Aughey, R.J. (2013). Acceleration Profiles in Elite Australian Soccer. Int J Sports Med. 34(1):34-9.