Match duration, high-intensity running, and collisions were associated with variations in EIMD markers, suggesting that recovery is dependent on individual match demands.

This aim of this study was to examine the validity of energy expenditure derived from microtechnology when measured during a repeated-effort rugby protocol. Sixteen male rugby players completed a repeated-effort protocol comprising 3 sets of 6 collisions during which movement activity and energy expenditure (EE) were measured using microtechnology. In addition, energy expenditure was estimated from open-circuit spirometry (EE). While related (r = .63, 90%CI .08-.89), there was a systematic underestimation of energy expenditure during the protocol (-5.94 ± 0.67 kcal/min) for EE (7.2 ± 1.0 kcal/min) compared with EE (13.2 ± 2.3 kcal/min). High-speed-running distance (r = .50, 95%CI -.66 to .84) was related to EE, while PlayerLoad was not (r = .37, 95%CI -.81 to .68). While metabolic power might provide a different measure of external load than other typically used microtechnology metrics (eg, high-speed running, PlayerLoad), it underestimates energy expenditure during intermittent team sports that involve collisions.

Estimated energy expenditure and time at high metabolic power can reflect changes in internal load. However, micro-technology cannot be used to determine the energy cost of intermittent running.

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