title: The IGF-1/cortisol ratio as a useful marker for monitoring training in young boxers.
abstract: Training effects on plasma insulin-like growth factor-1 (IGF-1)/cortisol ratio were investigated in boxers. Thirty subjects were assigned to either the training or the control group (n = 15 in both). They were tested before the beginning of training (T0), after 5 weeks of intensive training (T1), and after 1 week of tapering (T2). Physical performances (Yo-Yo intermittent recovery test level-1), training loads, and blood sampling were obtained at T0, T1, and T2. Controls were only tested for biochemical and anthropometric parameters at T0 and T2. A significantly higher physical performance was observed at T2 compared to T1. At T1, cortisol levels were significantly increased whereas IGF-1 and insulin-like growth factor binding protein-3 (IGFBP-3) levels remained unchanged compared to baseline. At T2, cortisol levels decreased while IGF-1 and IGFBP-3 levels increased. The IGF-1/cortisol ratio decreased significantly at T1 and increased at T2, and its variations were significantly correlated with changes in training loads and Yo-Yo intermittent recovery test level 1 (IRT1) performance over the training period. Cortisol variations correlated with changes in training load (r = 0.64; p < 0.01) and Yo-Yo IRT1 performance (r = 0.78; p < 0.001) at T1 whereas IGF-1 variations correlated only with changes in Yo-Yo IRT1 performance at T2 (r = 0.71; p < 0.001). It is concluded that IGF-1/cortisol ratio could be a useful tool for monitoring training loads in young trained boxers.
authors.affiliation: Research Laboratory, "Sport Performance Optimisation", National Centre of Medicine and Science in Sports, Tunis, Tunisia; University of Manouba, ISSEP, Ksar-Saïd, Tunisia.
authors.forename: S
authors.initials: S
authors.lastname: Nassib
authors.affiliation: University of Sfax, High Institute of Sport and Physical Education Sfax, Research Unit EM2S, Sfax, Tunisia.
authors.forename: W
authors.initials: W
authors.lastname: Moalla
authors.affiliation: Research Laboratory, "Sport Performance Optimisation", National Centre of Medicine and Science in Sports, Tunis, Tunisia; University of Manouba, ISSEP, Ksar-Saïd, Tunisia.
authors.forename: S
authors.initials: S
authors.lastname: Hammoudi-Nassib
authors.affiliation: Research Laboratory, "Sport Performance Optimisation", National Centre of Medicine and Science in Sports, Tunis, Tunisia; University of Manouba, ISSEP, Ksar-Saïd, Tunisia.
authors.forename: M
authors.initials: M
authors.lastname: Chtara
authors.affiliation: University of Manouba, ISSEP, Ksar-Saïd, Tunisia.
authors.forename: Y
authors.initials: Y
authors.lastname: Hachana
authors.affiliation: University of Sousse, Laboratory of Cardio-circulatory, Respiratory, and Hormonal Adaptations to Muscular Exercise, Faculty of Medicine Ibn El Jazzar, Sousse, Tunisia.
authors.forename: Z
authors.initials: Z
authors.lastname: Tabka
authors.affiliation: Athlete Health and Performance Research Centre, ASPETAR, Qatar Orthopaedic and Sports Medicine Hospital, Qatar.
authors.forename: K
authors.initials: K
authors.lastname: Chamari
authors.affiliation: University of Sousse, Laboratory of Cardio-circulatory, Respiratory, and Hormonal Adaptations to Muscular Exercise, Faculty of Medicine Ibn El Jazzar, Sousse, Tunisia; Blaise Pascal University, EA 3533: AME2P, Clermont-Ferrand, France; University of Manouba, ISSEP, Ksar-Saïd, Tunisia.
authors.forename: M
authors.initials: M
authors.lastname: Elloumi
keywords: Hormonal responses; Physical performance; Physiological demands; Training intensity; biochemical factor