Physiological and Sprint Kinetics Associated With the Yo-Yo Intermittent Recovery Test Level 1 Performances in Soccer Players

Background: The Yo-Yo Intermittent Recovery Test Level 1 (YYIR1) is often utilized to indirectly assess the cardiorespiratory fitness of team-sport athletes due to its proposed association with match-play high-speed running performance and predicted maximal oxygen uptake. No previous research has investigated the relationships between YYIR1 performances, actual oxygen uptake recorded during the YYIR1, and true all-out sprint kinetics (eg, maximal sprint speed, maximal force capacity, and maximal power output), which therefore served as the primary objective of this study. Objectives: To assess the true physiological kinetics ( VO2 and heart-rate responses) during the YYIR1 and to evaluate the correlations between the physiological kinetics, sprint kinetics, and YYIR1 performance parameters. Methods: A total of 23 amateur male soccer players were recruited for the study (age 22.52 [2.86] y; height 1.75 [0.06] m; body mass 65.61 [8.43] kg). Each participant completed a YYIR1 and 2 all-out sprint tests. Results: Significant differences were observed between actual and predicted maximal oxygen-uptake values (Mdiff = 17.57 mL center dot kg-1 center dot min-1, P< .001, r= .63). Shuttle distances showed statistically significant correlations with maximal sprint speed (r = .42, P = .044) and theoretic maximal speed (r = .44, P= .035). However, no other correlations with sprint kinetic parameters (eg, maximal force or power output) were observed. Conclusion: Practitioners should carefully consider the outcomes and utilities of the parameters derived from the YYIR1. The estimations of maximal oxygen uptake from shuttle performances as a proxy for cardiorespiratory fitness are not adequate. However, shuttle distances appear to be positively associated with all-out sprinting capacities.

Automated summary

The study found significant discrepancies between actual and predicted maximal oxygen uptake values in YYIR1, with shuttle distances showing positive correlations with sprint speed, but not with sprint kinetic parameters.