External, internal, perceived training loads and their relationships in youth basketball players across different positions

Purpose: To quantify external, internal, perceived training loads and their relationships in youth basketball players across different playing positions. Methods: Fourteen regional-level youth male players (age: 15.2 ± 0.3 years) were monitored during team-based training sessions across 10 in-season weeks. Players were monitored with BioHarness-3 devices, to measure external (Impulse Load, in N·s) and internal (Summated-Heart-Rate-Zones, SHRZ, in arbitrary units, AU) loads, and with the session Rating-of-Perceived-Exertion (sRPE, in AU) method to quantify perceived training load. Multiple linear mixed models were performed to compare training loads between playing positions (backcourt; frontcourt). Repeated-measures correlations were performed to assess relationships between load models, for all players and within playing positions. Results: External load (backcourt: 13599 ± 2260 N·s; frontcourt: 14934 ± 2173 N·s) and sRPE (backcourt: 345 ± 132 AU; frontcourt: 505 ± 158 AU) were higher in frontcourt (p< 0.05, ES: moderate), while SHRZ was similar between positions (backcourt: 239 ± 45 AU; frontcourt: 247 ± 43 AU) (p> 0.05; ES: trivial). Correlations were: large between external load and SHRZ (r= 0.57, p< 0.001); moderate between SHRZ and sRPE (r= 0.45, p< 0.001); and small between external load and sRPE (r= 0.26, p= 0.02). Correlation magnitudes were equivalent for external load-SHRZ (large) and SHRZ-sRPE (moderate) across positions, but different for the external load-sRPE correlation (small in backcourt; moderate in frontcourt). Conclusions: In youth basketball, small-large commonalities were found between training dose (external load) and players’ responses (internal, perceived loads). Practitioners should carefully manage frontcourt players since they accumulate greater external and perceived loads than backcourt