The learning effect in repeated Yo-Yo intermittent recovery tests in adults with different levels of physical fitness.

This pilot study investigates the learning effect in repeated trials of the Yo-Yo Intermittent Recovery Test in adults with different levels of physical fitness. Twenty physically active (PAS) and non-physically active subjects (NAS) participated in the study (age 19.9 ± 1.6 years, height 174.5 ± 8.1 cm, body mass 66.5 ± 8.2 kg, and BMI 21.8 ± 1.6 kg/m²). They repeatedly performed the Yo-Yo Intermittent Recovery Test (Level 1) once a week until performance plateaued. Maximal heart rate was analyzed in three one-minute intervals after the test was completed. PAS completed 3.1 ± 1.28 and NAS completed 2.7 ± 0.15 trials. Performance level significantly improved from the initial to the final trial in both PAS (from 14.5 ± 1.1 to 15.2 ± 1.1, p = .006) and NAS (from 13.0 ± 1.0 to 13.5 ± 0.9, p = .008). Similarly, the distance covered significantly increased in both the PAS (from 588.5 ± 317.4 m to 748.7 ± 373.4 m, p = .001) and the NAS (from 360.0 ± 175.9 m to 432.0 ± 188.4 m, p = .003). Maximal oxygen uptake also significantly increased in the PAS (from 41.6 ± 1.8 ml/kg/min to 43.3 ± 2.4 ml/kg/min, p = .005) as well as in the NAS (from 39.5 ± 1.5 ml/kg/min to 40.1 ± 1.6 ml/kg/min, p = .003). However, there were no significant changes in maximal heart rate between the first and last trials in either group. These findings indicate a significant learning effect in the Yo-Yo Intermittent Recovery Test (Level 1) over 3 trials, regardless of the subjects' level of physical fitness. However, this may bias the results, and therefore, practice trials are recommended before testing.