# The Relationship between Training Load Measures and Next-Day Well-Being in Rugby Union Players
## 4 Discussion  
The findings of this study are the first to examine the relationship between internal and external load measures with next-day subjective well-being in rugby union players during a competitive in-season period. External and internal load measures explained between 28% and 36% of the variance in next-day total WB with a 77% to 98% chance of a negative relationship. Therefore, these results question the suitability and validity  
\begin{table}
\begin{tabular}{l l c c c c c c} \hline \hline \multicolumn{1}{c}{**Load Measure**} & \multicolumn{6}{c}{**Well-Being Questionnaire (WB)**} \\ \hline  & & & **Sleep** & **Muscle** & **S Stress** & **Mood** & **Total** \\  & & & **Quality** & **Soreness** & **Levels** & & **Well-Being** \\ \hline sRPE (AU) & \(\mathbf{R}^{2}\) & **0.16** & **0.12** & **0.13** & **0.67** & **0.39** & **0.34** \\ HMM. = 509.20 & Estimate & \(-\)0.00 & \(-\)0.00 & \(-\)0.00 &  
of commonly used internal/external TL and well-being response measures to inform the training process. That is, an increase in TL would reduce (improve) a player's perception of total WB. Furthermore, the required load to produce a change of 1 in the total WB was between 15% and 24% for internal loads and between 15% and 29% of the mean match loads for the study period. Practically this requires weekly total distance to be reduced by 1809 m (32% of weekly mean TD) and HSD by 336 m (14% of weekly mean HSD). Whilst these values appear practical for individual conditioning training, removing players from team-based training is more challenging given the position specific demands involved in the tactical demands of rugby union. A range of internal load measures explained between 66% and 67% of the variance in changes in next-day subjective stress, with a 59% to 88% chance of a negative relationship. External load measures provided the most practical measures as they required a decrease in load of between 7% and 23% of the maximal match load to reduce perceived stress. The required change in load all internal load measures to change a player's wellbeing by one was greater than the maximal weekly loads reported in this study. Consequently, a player would have to miss an entire weeks training to improve their well-being score. Therefore, whilst internal loads demonstrate a strong relationship with next-day well-being, the results question the practical suitability and meaningfulness of this relationship. All other internal and external TL metrics explained similar or less of the changes in the next-day WB subscales. From a practical perspective, current technology allows coaches to monitor external loads in real time during training. Therefore, manipulating external load measures such as TD, PL and HSD during the training week provide the most practical measures to manage player's perceived stress levels as measured by the WB questionnaire. In academy rugby union players' wellbeing (motivation, recovery, sleep quality and muscle soreness) are sensitive to next-day changes following a high training load protocol [27]. Furthermore, wellbeing (fatigue, muscle strain, hamstring strain, pain/stiffness, power, sleep quality, stress) improved daily during the training week following high match loads in Australian Football players [28]. These findings contrast with previous findings in elite youth soccer players during the competitive in-season [29]. Relationships have been reported between sRPE and pre-training subjective well-being (WB) in collegiate American football players [28], professional soccer players [29] and Australian football players [30,31]. These previous studies identified have explained between 7% and 37% of the variance between sRPE and changes in perceptions of sleep, fatigue, stress and muscle soreness. Importantly, these studies compared subjective well-being immediately before training. It has previously been suggested that these pre-exercise well-being questionnaires are valid and reliable tools to identify changes in perceived fatigue in team sports [28]. Recently [PERSON] et al.