Abstract
Most soccer matches are conducted by coaches who usually make all player substitutions allowed. Therefore, it is extremely important to study these substitutions and their effects on the intensity of effort required from players. To date, no published studies have reported on this topic using heart rate (HR) as an intensity parameter. The objective of this study was to compare effort intensity (EI) of soccer players in the following situations: 1) first half (FH-EI); 2) second half (SH-EI); 3) second half with substitutions(SHS-EI). Forty-five male soccer players (18.5±1.2 years old, 74.25±5.79 kg, 182.6±8.55 cm, 9.56±2.47% body fat, 56.3±4.3 mLO2/kg/min) were evaluated during 29 official games. EI was considered as the mean HR, expressed as the percentage of each player’s maximal HR (%HRmax) and as the time spent in each intensity zone (Z) according to %HRmax (Z1<70%; Z2 70-85%; Z3 85-90%; Z4 90-95%; Z5 95-100%). FH-EI (86.3±3.3%HRmax) was higher than SH-EI (80.6±4.4%HRmax) and SHS-EI (83.6±2.8%HRmax). SHS-EI was higher than SH-EI (p<0.05). Time spent in high-intensity zones was lower in SH-EI than in FH-EI, buthigher in SHS-EI when compared to SH-EI (p<0.05). It was concluded that the decrease in EI in the second half of soccer matches was attenuated by substitutions made at halftime, as evidenced by a longer time spent in high-intensity zones when compared to SH-EI.
Highlights
The work load imposed on soccer players during an official match has been described by several variables, such as distance covered[1], average running speed[2], body temperature[3], oxygen uptake, blood lactate concentration[4], mean energy expenditure[5], and heart rate (HR)[6,7,8,9,10]
FH-effort intensity (EI) showed the highest percentage of time spent in zone 4 (p
A decrease in EI was observed in both second halves (SH-EI and SHS-EI) when compared to the first half (FH-EI) of soccer games
Summary
The work load imposed on soccer players during an official match has been described by several variables, such as distance covered[1], average running speed[2], body temperature[3], oxygen uptake, blood lactate concentration[4], mean energy expenditure[5], and heart rate (HR)[6,7,8,9,10]. Among these variables, the direct measurement of oxygen uptake (VO2) would provide the optimal standard for assessing the intensity of effort required from players during an official competition. This variable may represent an adequate parameter to control exercise intensity in professional and non-professional soccer players[14]
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