The puzzle of monitoring training load in winter sports - A hard nut to crack?

Elite winter sports have become increasingly professionalized and commercialized, often accompanied by congested competition schedules. This has brought the topic of load management, i.e., planning, monitoring, and adaptation, enormous attention in the scientific community. In this review, we summarize the general knowledge from various sports about training load and its effects on injuries and illnesses. After outlining the fundamentals of load monitoring, we present common monitoring tools, i.e., neuromuscular performance tests, heart rate measures, blood-based biomarkers, and questionnaires and discuss their potentials and pitfalls in application. Studies have identified training load-related variables, but also other factors such as travelling, previous injuries, or age contributing to the occurrence of illness and injury. Based on our findings, the use of monitoring tools must be context-specific and long-term, considering statistical aspects as well. Promising study designs and future perspectives are finally highlighted, with the general conclusion that there is still a clear need for research on this topic in general and in the field of winter sports in particular.