Quantifying the relationship between internal and external work in team sports: development of a novel training efficiency index

ABSTRACT

Objective: To establish whether a simple integration of selected internal and external training load (TL) metrics is useful for tracking and assessing training outcomes during team-sport training.

Methods: Internal [heart rate training impulse (HR-TRIMP), session rating of perceived exertion (sRPE-TL)] and selected external (global positioning systems; GPS) metrics were monitored over seven weeks in 38 professional male rugby league players. Relationships between internal and external measures of TL were determined, and an integrated novel training efficiency index (TE_I) was established. Changes in TE_I were compared to changes in both running performance (1.2 km shuttle test) and external TL completed.

Results: Moderate to almost perfect correlations (r = 0.35–0.96; ±~0.02; range ± 90% confidence limits) were observed between external TL and each measure of internal TL. The integration of HR-TRIMP and external TL measures incorporating both body mass and acceleration/deceleration were the most appropriate variables for calculating TE_I, exhibiting moderate (ES= 0.87–0.89; ±~0.15) and small (ES = 0.29–0.33; ±~0.07) relationships with changes in running performance and completed external TL respectively.

Conclusions: Combination of the TE_I and an athlete monitoring system should reveal useful information for continuous monitoring of team-sport athletes over several weeks.

KEYWORDS:

• Player monitoring
• fitness
• global positioning systems
• training load
• validity

Acknowledgements

No external financial support was required or accepted for this study. The authors have no conflicts of interest to disclose. The results of the present study do not constitute endorsement by the American College of Sports Medicine. The results of this study are presented clearly, honestly and without fabrication, or inappropriate data manipulation. The authors would like to thank Mr Craig O’Brien (Head of Mathematics, Bishop Tyrrell Anglican College, Fletcher, NSW, Australia) for assistance in the modelling and development of the TE_I.

Disclosure statement

The authors have no conflicts of interest to disclose.

Additional information

Funding

No external financial support was required or accepted for this study.