Unravelling the Relationship between External Load and the Incidence of Hamstring Injuries in Professional Soccer Players

Abstract

Objectives. The study aimed to analyze external load indicators with the incidence of non-contact hamstring injuries. Material and methods. A non-experimental correlative, retrospective cohort study was carried out. The data were collected from 31 professional male soccer players over the course of one season. The following load indicators were examined: duration (D), total distance travelled (TDT), distance travelled at high intensity (DTHI) > 20km/h, number of efforts between 20-25 km/h (NE 20-25km/h), distance travelled at more than 25km/h (DR+25km/h), number of sprints greater than 25km/h (NE > 25km/h), number of accelerations greater than 1m/s² (Acc), and number of minor decelerations at -1m/s² (Dcc). Only non-contact hamstring injuries were included in the analysis. For the multivariate analysis, we applied a logistic regression model, where a value of P < 0.05 was established both for the statistical significance of the model (X²) and for each of the regressor variables (X²), the confidence interval level was 95%. Results. Two injuries were recorded and diagnosed: injury grade 2 and muscle fatigue. The load indicators analyzed did not show a significant correlation with hamstring injury. Therefore, no association was found between external load and hamstring injury in professional soccer players. Conclusions. The logistic regression model (p > 0.05) did not present statistical significance. Consequently, none of the external load variables monitored explain the rate of non-contact hamstring injuries in this population.