Maturity associated considerations for training load, injury risk and physical performance within youth soccer: one size does not fit all

Biological maturation can be defined as the timing and tempo of progress to achieve a mature state. The estimation of age of peak height velocity (PHV) or percentage of final estimated adult stature attainment (%EASA) is typically used to inform the training process in young athletes. In youth soccer, maturity-related changes in anthropometric and physical fitness characteristics are diverse between individuals, particularly around PHV. During this time, players are also at an increased risk of sustaining an overuse or growth-related injury. As a result, the implementation of training interventions can be challenging. The purpose of this review is to (i) highlight and discuss many of the methods which can be used to estimate maturation in the applied setting, (ii) discuss the implications of manipulating training load around PHV on physical development and injury risk. We also have provided key stakeholders with a practical online tool for estimating player maturation status (see online supplementary maturity estimation tool[s]). Whilst useful to guide the training process, practitioners should be aware of the limitations when estimating maturity using predictive equations. To increase the accuracy and usefulness of data, it is also vital that sports scientists implement reliable testing protocols at predetermined time-points.