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

Area of Science:

• Sports Science
• Exercise Physiology
• Rugby Union Performance Analysis

Background:

• Optimizing training load (TL) is crucial for enhancing aerobic fitness in elite athletes.
• Understanding the dose-response relationship between different TL metrics and fitness adaptations is essential for effective training prescription.

Purpose of the Study:

• To determine the dose-response relationship between various training load measures and changes in maximal aerobic fitness.
• To identify the most effective training load metrics for predicting aerobic fitness improvements in academy rugby union players.

Main Methods:

• Collected training data and conducted lactate-threshold tests on 10 academy rugby union players over a 6-week in-season period.
• Assessed aerobic fitness using VO2max, velocity at VO2max, lactate threshold, and velocity at onset of lactate accumulation (vOBLA).
• Calculated internal TL (Banister TRIMP, Edwards TRIMP, Lucia TRIMP, iTRIMP, sRPE) and external TL (total distance, PlayerLoad™, high-speed distances).

Main Results:

• Banister training impulse (bTRIMP) explained 78% of the variance in VO2max changes (R² = .78, P = .005).
• Individualized training impulse (iTRIMP) explained 55% of the variance in VO2max changes (R² = .55, P = .063).
• Other internal and external TL measures explained less than 42% of the variance in aerobic fitness changes.

Conclusions:

• Banister training impulse (bTRIMP) and individualized training impulse (iTRIMP) demonstrate a curvilinear dose-response relationship with maximal aerobic fitness.
• These specific internal training load metrics are superior predictors of aerobic fitness adaptations in rugby union players.