Quantifying the external and internal loads of professional rugby league training modes: consideration for concurrent field-based training prescription Dan Weaving1,2 (d.a.weaving@leedsbeckett.ac.uk; @DanWeaving), Phil Marshall1, Keith Earle1, Ben Jones2, Kevin Till2, & Grant Abt1 Introduction Professional rugby league players require a wide range of physical and technical qualities to attain successful competitive performance. To induce varied training adaptations, practitioners concurrently prescribe multiple modes of training yet how the external and internal loads of these modes differ per minute of training time has yet to be established. Method External (velocity- and metabolic-power-derived threshold distances) and internal (iTRIMP and sRPE) training load data were collected from 17 professional players from one European Super League club during two 12-week pre-season periods (n = 716 sessions). This data were categorised by 4 training modes (conditioning [CON], SSG, skills and speed). The total session load for each measure were divided by session duration with the differences between each mode assessed using magnitude based inferences and Cohen’s d effect size (ES). Results iTRIMP, was almost certainly greater during CON than skills (ES [descriptor]: 2.37 [very large]) and speed (2.91 [very large]) training whilst this was unclear (0.02 [trivial]) between CON and SSG. iTRIMP was almost certainly greater during SSG than skills (2.35 [very large]) and speed (2.89 [very large]). The difference in iTRIMP between skills and speed was unclear (0.54 [small]). sRPE was likely greater during CON vs SSG (0.61 [moderate]) and almost certainly greater during CON vs skills (6.49 [very large]) and speed training (8.21 [very large]). sRPE was almost certainly greater during SSG vs skills (5.89 [very large]) and speed training (7.60 [very large]). sRPE was very likely greater during skills vs speed (1.71 [large]). Fig A & B. The difference in the metabolic-power- (Fig A) and velocity-derived-threshold distances (Fig B) for each training mode comparison. Abbreviations: EQ = equivalent distance; TD = total distance. Metabolic-Power-Distances (W·kg-1): LP: low power (0-9.9); IP: intermediate power (10-19.9); HP: high power (20-34.9); EP: elevated power (35-54.9); MP: maximal power (≥ 55). Velocity-Distances (m·s-1): walk: (0-1.94); jog: (1.95-3.87); stride:(3.88-5.4); sprint: (≥ 5.5) Conclusions SSG and CON expose players to the greatest relative external and internal loads, although speed training provides the greatest near-maximal external load stimulus without a concomitant increase in internal load. Establishing the typical loads per minute of training time for players during training modes can be used to periodise the overall field-based programme by multiplying the relative load by the planned session duration. BASES 2016 Conference, East Midlands Conference Centre, 29-30 November 2016