Reliability, Reproducibility, and Individual Responses of Running Economy Measures in Different Advanced Footwear...

This study aimed to evaluate the reliability and reproducibility of running economy measurements across multiple days and within the same day using 2 models of advanced footwear technology.

Thirteen trained male runners (age: 27.6 [8.2] y; body mass: 64.4 [6.1] kg; height: 1.74 [0.06] m) completed 4 treadmill sessions separated by 7 days. Two advanced footwear technology models were tested in a randomized crossover design. Each session included two 5-minute trials per shoe condition at 13 km·h-1. Reliability and reproducibility of running economy measures were evaluated using intraclass correlation coefficients (ICCs), SEM, coefficient of variation, and smallest worthwhile change.

Intrasession ICCs and coefficient of variations for oxygen cost and metabolic cost were excellent for both shoe conditions (.917 and .945; .921 and .948; ∼1%). Intersession reliability was good (oxygen cost ICC = .819; metabolic cost ICC = .849), though coefficient of variations increased (∼2%). No significant differences in metabolic variables were observed between footwear models (P ≥ .05), and high variability was observed between individuals. Day-to-day variability affected oxygen cost and metabolic cost (P < .05), independent of shoe condition.

Running economy measurements are highly reliable within sessions but demonstrate moderate variability across days. Despite mechanical differences in footwear conditions, no differences were observed between the 2 models. These findings highlight the importance of multitrial, multiday, and individual testing when evaluating footwear conditions.