Adaptations to speed endurance training in highly trained soccer players

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Purpose: The present study examined whether a period of additional speed endurance training would improve intense intermittent exercise performance in highly trained soccer players during the season and whether the training changed aerobic metabolism and the level of oxidative enzymes in type I and II muscle fibers.

Methods: During the last nine weeks of the season, thirteen semi-professional soccer players performed additional speed endurance training sessions consisting of 2-3 sets of 8 - 10 repetitions of 30 m sprints with 10 s of passive recovery (SET). Before and after SET, subjects completed a double-step exercise protocol that included transitions from standing to moderate-intensity running (∼75% of maximal heart rate (HRmax)) followed by transitions from moderate to high-intensity running (∼90% HRmax) in which pulmonary oxygen uptake (V˙O2) was determined. In addition, the Yo-Yo Intermittent Recovery Test level 1 (YYIRT-1) was performed and a muscle biopsy was obtained at rest.

Results: YYIRT-1 performance was 11.6±6.4% (mean±SD) better (2803±330 vs. 3127±383 m, P<0.05) after compared to before SET. In the transition from standing to moderate-intensity running, phase II pulmonary V˙O2 kinetics was 11.4±16.5% faster (P<0.05) and running economy at this intensity was 2.3±3.0% better (P<0.05). These improvements were apparent despite the content of muscle proteins regulating oxidative metabolism (HAD, COX IV and OXPHOS) and capillarization were reduced (P<0.05). The content of HAD and CS in type I and II fibers did not change.

Conclusion: In highly trained soccer players, additional speed endurance training is associated with an improved ability to perform repeated high-intensity work. To what extent the training-induced changes in V˙O2 kinetics and mechanical efficiency in type I fibers caused the improvement in performance warrants further investigation.

Original languageEnglish
JournalMedicine and Science in Sports and Exercise
Issue number7
Pages (from-to)1355-1364
Number of pages10
Publication statusPublished - 2016

ID: 156365139