The Dose-Response Relationship Between Training Load and Aerobic Fitness in Academy Rugby Union Players

Taylor, R.; Sanders, D.; Myers, T.; Abt, G.; Taylor, C. A.; Akubat, I.

Purpose: This study aimed to determine the dose-response relationship between measures of training load (TL) and changes in aerobic fitness among academy rugby union players.

Method: Training data were collected from ten academy rugby union players over a six-week in-season period. Participants underwent a lactate threshold (LT) test to assess various measures of aerobic fitness, including VO2max, velocities at specific lactate thresholds (vLT and vOBLA). Internal training load measures included Banister’s TRIMP (bTRIMP), Edward’s TRIMP (eTRIMP), Lucia’s TRIMP (luTRIMP), individualized TRIMP (iTRIMP), and session-RPE (sRPE). External TL measures included total distance (TD), PlayerLoadTM (PL), high-speed distance (>15 km/h), very high-speed distance (>18 km/h), and individualized high-speed distance based on each player’s vOBLA (iHSD).

Results: A quadratic regression analysis revealed that bTRIMP explained 78% of the variance (R2 = 0.78, P = 0.005) in changes in VO2max, while iTRIMP explained 55% of the variance (R2 = 0.55, P = 0.063). Other HR-based internal TL measures and sRPE explained less than 40% of the variance in fitness changes. Similarly, external TL measures explained less than 42% of the variance in fitness changes.

Conclusions: Among rugby players, bTRIMP and iTRIMP exhibit a curvilinear dose-response relationship with changes in maximal aerobic fitness. These findings suggest that certain internal TL measures may better predict changes in aerobic fitness compared to others, highlighting the importance of considering different TL metrics when designing training programs for rugby players.

View this research