Performance in the Yo-Yo Intermittent Recovery Test May Improve with Repeated Trials: Does Practice Matter?

The Yo-Yo Intermittent Test is frequently used to monitor changes in athletes' performance in response to different interventions. However, the question remains as to whether, and to what extent, retakes of this test would contribute to these changes. This case study sought to determine the magnitude of practice effects, involving test repetition, on performance in the Yo-Yo Intermittent Recovery Test. A recreational soccer player performed four attempts of the Yo-Yo Intermittent Recovery Test-Level 1 (YYIR1) with a week's rest in between. The same participant repeated this test protocol (four attempts of the YYIR1) again after six months. Changes in distance covered, level achieved, maximal oxygen uptake, and heart rate between the first and last attempt were assessed. The smallest worthwhile change (SWC), the coefficient of variation (CV), and the 2CV were calculated to identify a trivial, a possibly meaningful, and a certainly meaningful change in YYIR1 performance. The distance covered in the first set of measurements increased from 1320 m to 1560 m (15.4%), which corresponds to a 4.6% increase in the level achieved (from 16.6 to 17.4). Similarly, the distance covered in the second set of measurements increased from 1280 m to 1560 m (17.9%), which corresponds to a 5.5% increase in the level achieved (from 16.5 to 17.4). The participant's performance changes fell outside of the SWC and the CV, but not the 2CV during both sets of measurements. These improvements in YYIR1 performance may be ascribed to practice with repeated attempts of the test by improving running technique at the turning point and/or by simply increasing the linear speed. This fact should always be kept in mind when interpreting the effects of training. Practitioners should differentiate between practice effects associated with repeated test execution and adaptation induced by conducting sport-specific training.

Sprint Endurance Abilities in Elite Female Soccer Players

PURPOSE

To profile sprint endurance performance of elite-level female soccer players.

METHODS

Twenty-five female national-team soccer players (age 25.1 [2.7] y, body mass 59.6 [3.6] kg, height 168.5 [4.1] cm) were tested for sprint endurance, performing 5 maximal sprints, interspersed with 30 seconds of active recovery (5 × 30 m) and a 30-second all-out shuttle run in a soccer pitch. The Yo-Yo Intermittent Recovery Test level 1 (YYIR1) evaluated intermittent high-intensity endurance under the same field-testing conditions. Maximal anaerobic capacity was assessed while participants performed three 10-second all-out bouts separated by 20 seconds of passive recovery (3 × 10 s) on a nonmotorized treadmill.

RESULTS

Huge interplayer variability was observed for sprint decrements in 3 × 10 seconds (coefficient of variation = 37%) and 5 × 30 m (coefficient of variation = 62%). The 3 × 10 performance was largely associated with 5 × 30-m mean and best time and very largely with 30 seconds. A very large and nearly perfect correlation was observed between 30 seconds and 5 × 30 mMean (r = -.86) and 5 × 30 mBest (r = -.92), respectively. The YYIR1 was moderately to largely associated with 5 × 30-m variables and 30 seconds, respectively. A nearly perfect association was observed between 5 × 30 mBest and 5 × 30 mMean (r = .97).

CONCLUSIONS

Elite female soccer players' sprint endurance variables are characterized by remarkable variability. Associations between sprint endurance variables suggest physiological interdependence and a likelihood of a general ability in sustaining sprinting in this population.

Effects and sustainability of a 13-day high-intensity shock microcycle in soccer

The preseason in soccer is a short period of 6-8 weeks where conditional abilities, technical and tactical elements need to be trained. Therefore, time is lacking to perform long term preparation periods for different abilities, especially endurance training. There is evidence that the implementation of high-intensity shock microcycles in preseason training could be one way to improve physical performance in a short period of time. Therefore, the purpose of the present study was to examine the effects and the sustainability of a high-intensity shock microcycle on soccer specific performance. Over 2 weeks, 12 male soccer players (26.1 ± 4.5 years) performed 12 high-intensity training (HIT) sessions in addition to their usual training. Before (pre), 6 days (6d) and 25 days (25d) after training, subjects performed Counter Movement Jump (CMJ), Repeated-Sprint Ability (RSA) test and Yo-Yo Intermittent Recovery Test Level 2 (YYIR2). Mean sprint time (RSAMean) (cohen's d = -1.15), percentage decrement score (RSAIndex) (cohen's d = -1.99) and YYIR2 (cohen's d = +1.92) improved significantly from pre to 6d. 25d after, values showed a significant reduction for YYIR2 (cohen's d = -0.81) and small to moderate but not significant increase for RSAMean (cohen's d = +0.37) and RSAIndex (cohen's d = +0.7) compared to 6d values. Small but no significant increases were found for CMJ (cohen's d = +0.33) and no significant and substantial changes were found for RSABest (cohen's d = -0.07) from pre to 6d. For competitive soccer players, block periodization of HIT offers a promising way to largely improve RSA and YYIR2 in a short period of time. Despite moderate to large decreases in RSAIndex and YYIR2 performance in the 19 day period without HIT, values still remained significantly higher 25d after the last HIT session compared to pre-values. However, it might be necessary to include isolated high-intensity sessions after a HIT training block in order to maintain the higher level of YYIR2 and RSAIndex performance. Key pointsHIT shock microcycle increases performance in semi-professional soccer players in a short period of time.Despite moderate to large decreases in performance in the 19 day period without HIT, values still remained significantly higher 25d after the last HIT session compared to pre-values.This kind of training block increases YYIR2 performance and the ability to repeated sprints, based on the RSAIndex.