Analysis of relationships between different training load monitoring tools in elite U-20 soccer

Purpose
The study analysed the responses from different training load monitoring tools in the elite U-20 soccer category and checked the level of association between these responses.

Methods
The participants were 10 elite male soccer players (age, 18.61 ± 0.95 years; height, 176.81 ± 5.03 cm; body mass, 70.32 ± 8.41 kg). The progressive test to exhaustion assessed maximum oxygen consumption and maximum heart rate. The athletes were monitored over 15 training sessions with a heart-rate-based method (Edwards) and mechanical load indicators obtained from GPS devices (15 Hz).

Results
Individual training load was calculated with the Foster’s session rating of perceived exertion (session-RPE) procedure. A significant correlation was found between session-RPE and Edwards (0.564, p < 0.05). There were no significant correlations between session-RPE and average speed (–0.161), average heart rate of the training session (–0.187), distance over 20 km/h (0.006), or number of accelerations performed in different zones (–0.194, –0.178, –0.171, –0.236). The Edwards method showed significant correlations with the total distance (0.642, p < 0.01), average heart rate (0.333, p < 0.01), and distances covered at 0–20 km/h (0.634, p < 0.01; 0.568, p < 0.01; 0.424, p < 0.01; 0.289, p < 0.01; 0.201, p < 0.015). There were no significant correlations between Edwards and average speed (0.158), distance over 20 km/h (0.014), number of accelerations performed in different zones (–0.194, –0.178, –0.171, –0.236), or number of normalized accelerations (–0.118, –0.038, –0.058, –0.035).

Conclusions
The Edwards method and session-RPE are limited load monitoring tools to indicate the reality of training situations (high-intensity action with recovery intervals).