Multimodal Training-Load Monitoring in Youth Sport: A Scoping Review of Monitoring Metrics, Individualised Decision-Making, and Implications for Strength and Conditioning

Training-load monitoring in youth sport should consider external workload, internal response, athlete state, and developmental context. This scoping review synthesised multimodal monitoring approaches and examined their use in individualised training decisions. PubMed/MEDLINE, Web of Science, and Scopus were searched, and 20 of 78 records met the eligibility criteria. Common measures included training duration, running exposure, sRPE, heart rate, neuromuscular performance, wellness, and sleep. Growth and biological maturity were considered important but were inconsistently integrated. Evidence was concentrated in soccer and male academy team sports, with limited representation of female athletes, individual sports, and resistance training. Monitoring was used mainly to describe workload, readiness, and within-athlete change, while evidence supporting specific training-adjustment protocols remained limited. Multimodal monitoring may inform coach-led decisions when interpreted against individual trends and developmental context. Prospective studies are needed to confirm its effects on training adaptation and athlete health.