Workload efficiency as a new tool to describe external and internal competitive match load
Workload efficiency as a new tool to describe external and internal competitive match load of a professional soccer team: A descriptive study on the relationship between pre-game training loads and relative match load.
Grünbichler J, Federolf P & Gatterer H. Workload efficiency as a new tool to describe external and internal competitive match load of a professional soccer team: A descriptive study on the relationship between pre-game training loads and relative match load. European J Sports Sci, 2019.
- DOI: 10.1080/17461391.2019.1697374
Introduction: Evaluating players’ physical performance in games by solely analyzing external load variables, and ignoring internal load (e.g., heart rate responses, perceived exertion) would be far too reductionist and there is a need for a combined variable that represents players overall workload during soccer games. A possible way to deal with this issue is to express physical performance and strain as a relative variable. Previous authors described a basic “efficiency index” with total distance. New index to quantify the load is necessary, an index based on the earlier concept of the “efficiency index” yet including several internal (e.g., HR, training impulse) and external (e.g., running distance, sprinting distance, acceleration, deceleration) training and match load parameters.
a) To develop and introduce a new index, named workload efficiency, based on earlier concepts of internal and external workload ratios.
b) To analyze and describe how match workload efficiency was influenced by the training loads during the five days before the match.
Method: Healthy male (n = 14; age, 22.6 ± 4.3 yrs) professional soccer players of an Austrian Second League team took part in the study. Workload efficiency was calculated for each match as the ratio between overall external and internal load. A multiple stepwise regression analysis (including z-transformed variables) was used to determine training load variables that predict workload efficiency of the following matches.
– The newly introduced workload efficiency index during the matches was influenced by sprinting distance at D-3 (β = .477, p < .001), total distance at D-1 (β = .380, p < .001), sprinting distance at D-4 (β = .312, p < .001), PTL at D-1 (β = -.259, p = .001) and training duration at D-1 (β = -.216, p = .007).
– The five predictor variables explained 26.6 % of the variance (corrected R2 of .266, F (5, 174) = 13.9512, p < .000).
– Training load data show that mean internal and external load increase from D-5 over D-4 with a peak on D-3.
– Internal and external load are subsequently lower on D-2 and decrease to lowest scores on D-1 (Table 2).
Take home messages
– The “workload efficiency” index proposed by these authors can be a complete tool that includes several internal and external load variables.
– The sprinting distance four and three days before a match and the total distance one day before a match seem beneficial for players’ physical efficiency in the upcoming game. However, high and long training session a previous day before a match will negatively influence players’ workload efficiency.