Reliability and Validity of Integrated External and Internal Load Ratios as Measures of Fitness in Academy Rugby Union Players.

Richard Taylor, Ibrahim Akuabt, Tony Myers, Dajo Sanders

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)


This study aimed to assess the relationships between integrated ratios of external and internal load measures and aerobic fitness in 3 different training exercise protocols. Twelve academy rugby union players (aged; 17.6 ± 0.44 years, height; 179.4 ± 6.3 cm, body mass 83.3 ± 9.7 kg) performed a lactate threshold/V̇o2max test (LT/V̇o2max) followed by 3 exercise protocols; 760 m continuous shuttle running (20 m shuttle run at 9 km·h−1), sprint interval training (SIT: 6 × 6 seconds sprint with 54 seconds recovery), and a small-sided game (SSG: 6 vs. 6, 10 minutes on a 39 × 51 m pitch) on 2 occasions. A LT/V̇o2max test was used to determine velocity at lactate threshold (vLT) and at the onset of blood lactate accumulation (vOBLA), maximal oxygen uptake (V̇o2max) and the heart rate-blood lactate profile for the calculation of internal load (individualized training impulse or iTRIMP). The total distance (TD), PlayerLoad, metabolic power (MP), high-speed distance >15 km·h−1 (HSD), very high-speed distance >18 km·h−1 (VHSD) and individualized high-speed distance based on each player's vOBLA (iHSD) for the 3 exercise protocols were measured using Micro Electro Mechanical Systems/Global Positioning System technology. Bayesian analysis was used to assess the ratios validity and reliability. Ratios demonstrated large-to-very large associations with vOBLA (Rho = 0.64–0.76), vLT (Rho = 0.63–0.71). Reliability of the ratios ranged from 7.06 to 36.28% (coefficient of variation [CV]%). The results suggest that integrated load ratios from the SIT and SSG protocols provide a measure which is reliable with large-to-very large associations to submaximal aerobic fitness in rugby union.
Original languageEnglish
Pages (from-to)1723-1730
Number of pages8
JournalJournal of Strength and Conditioning Research
Issue number6
Publication statusPublished - Jun 2020
Externally publishedYes


  • GPS
  • Heart rate
  • Training impulse

ASJC Scopus subject areas

  • Physical Therapy, Sports Therapy and Rehabilitation
  • Orthopedics and Sports Medicine


Dive into the research topics of 'Reliability and Validity of Integrated External and Internal Load Ratios as Measures of Fitness in Academy Rugby Union Players.'. Together they form a unique fingerprint.

Cite this