Quantifying The External And Internal Loads Of Professional Rugby League Training Modes: Consideration For Concurrent Field-Based Training Prescription.Weaving, Dan; Jones, Ben; Till, Kevin; Marshall, Phil; Earle, Keith; Abt, GrantJournal of Strength & Conditioning Research: Post Acceptance: September 11, 2017 doi: 10.1519/JSC.0000000000002242 Original Research: PDF Only Abstract Practitioners prescribe numerous training modes to develop the varied physical qualities professional rugby league players must express during competition. The aim of the current study was to determine how the magnitude of external and internal training load per minute of time differs between modes in professional rugby league players. This data were collected from 17 players across 716 individual sessions (mean (SD) sessions: 42 (13) per player) which were categorised by mode (conditioning, small sided games, skills and sprint training). Derived from global positioning systems (5Hz with 15Hz interpolation), the distances covered within arbitrary speed- and metabolic-power-thresholds were determined to represent the external load. Session rating of perceived exertion (sRPE) and individualised training impulse (iTRIMP) represented the internal load. All data were made relative to session duration. The differences in time-relative load methods between each mode were assessed using magnitude based inferences. Small-sided-games and conditioning very likely to almost certainly produced the greatest relative internal and external loads. Sprint training provided players with the greatest sprinting and maximal-power distances without a concomitant increase in internal load. The metabolic-power method complements speed-based quantification of the external load, particularly during smallsided-games and skills training. In practice, establishing normative loads per minute of time for each mode can be useful to plan future training by multiplying this value by the planned session duration. Copyright (C) 2017 by the National Strength & Conditioning Association.