Analyse Success Model of Split Time and Cut-Off Point Values of Physical Demands to Keep Category in Semi-Professional Football Players

Abstract

The aim of this study was to analyse different success models and split time on cut-off point values on physical demands to keep category in semi-professional football players. An ad hoc observational controlled study was carried out with a total of ten (840 match data) outfield main players (25.2 ± 6.3 years, 1.79 ± 0.75 m, 74.9 ± 5.8 kg and 16.5 ± 6 years of football experience) and monitored using 15 Hz GPS devices. During 14 official matches from the Spanish division B in the 2016/2017 season, match data were coded considering the situational variable (score) and classified by match results (winning, losing or drawing). The results show significant differences between high-intensity attributes criteria that considered split time in velocity zones of 0–15 min (p = 0.043, ηp2 = 0.065, medium), 30–45 min (p = 0.010, ηp2 = 0.094, medium) and 60–75 min (p = 0.015, ηp2 = 0.086, medium), as well as sprint 60–75 min (p = 0.042, ηp2 = 0.066, medium) and 75–90 min (p = 0.002, ηp2 = 0.129, medium). Decision tree induction was applied to reduce the disparity range of data according to six 15-min intervals and to determine the cut-off point values for every parameter combination. It was possible to establish multivariate models for the main high-intensity actions criteria, allowing the establishment of all rules with their attributes and enabling the detection and visualisation of relationships and the pattern sets of variables for determining success.

Changes in Muscle Activity Imbalance of the Lower Limbs Following 3 Weeks of Supplementary Body-Weight Unilateral Training

“…The sEMG data were collected during two 10 s runs (separated by a 1 min rest) at a speed of 18km/h on a treadmill (Matrix T5X) at baseline and after 3 weeks of training. This treadmill running speed was chosen since it was considered as the low range value of a high-speed running zone in previous studies in soccer players [25][26][27] and was well tolerated by all participants of this study. A standardized warm-up preceded testing that included 10 min of jogging, followed by 2 short accelerations (20 m) and dynamic stretching for the major muscle groups.…”