Changes in performance markers and wellbeing in elite senior professional rugby union players during a pre-season period : analysis of the differences across training phases

Objectives: To assess the magnitude of change and association with variation in training load of twoperformance markers and wellbeing, over three pre-season training blocks, in elite rugby union athletes.Design: Observational.Methods: Twenty-two professional players (age 25 ± 5 years; training age 6 ± 5 years; body mass,99 ± 13 kg; stature 186 ± 6 cm) participated in this study, with changes in lower (CMJ height) and upperbody (bench press mean speed) neuromuscular function and self-reported wellbeing (WB) assessedduring an 11-week period.Results: There was a small increase in CMJ height (0.27, ±0.17 – likely substantial; standardised effectsize, ±95% confidence limits – magnitude-based inference) (p = 0.003), bench press speed (0.26, ±0.15 –likely substantial) (p = 0.001) and WB (0.26, ±0.12 – possibly substantial) (p < 0.0001) across the pre-seasonperiod. There was a substantial interaction in the effect of training load on these three variables acrossthe three training phases. A two-standard deviation (2SD) change in training load was associated with:a small decrease in CMJ height during the power phase (−0.32, ±0.19 – likely substantial) (p = 0.001); asmall reduction in bench press speed during the hypertrophy phase (−0.40, ±0.32 – likely substantial)(p = 0.02); and a small reduction in WB during the strength phase (−0.40, ±0.24 – very likely substantial)(p < 0.0001). The effects of changes in training load across other phases were either likely trivial, onlypossibly substantial, or unclear.Conclusions: The effect of training load on performance can vary both according to the type of trainingstimulus being administered and based on whether upper- or lower-body outcomes are being measured