ORIGINAL ARTICLE  EXERCISE PHYSIOLOGY AND BIOMECHANICS 

The Journal of Sports Medicine and Physical Fitness 2018 July-August;58(7-8):980-9

DOI: 10.23736/S0022-4707.17.07048-7

Copyright © 2017 EDIZIONI MINERVA MEDICA

language: English

Acute and delayed responses of steroidal hormones, blood lactate and biomarkers of muscle damage after a resistance training session: time-of-day effects

Achraf AMMAR ^{1, 2} ✉, Hamdi CHTOUROU ^{1, 3}, Mouna TURKI ⁴, Omar HAMMOUDA ⁵, Ahmed CHAARI ¹, Mariem BOUDAYA ⁴, Tarak DRISS ⁵, Fatma AYEDI ⁴, Nizar SOUISSI ²

¹ Unit of Research: Education, Motricity, Sport and Health, UR15JS01, High Institute of Sport and Physical Education of Sfax, Sfax University, Sfax, Tunisia; ² National Observatory of Sport, Tunis, Tunisia; ³ High Institute of Sport and Physical Education, Sfax University, Sfax, Tunisia; ⁴ Laboratory of Biochemistry, CHU Habib Bourguiba, Sfax University, Sfax, Tunisia; ⁵ Research Center on Sport and Movement (EA 2931), University of Paris Ouest La Defense, Nanterre, France

BACKGROUND: The present study aimed to investigate the effect of time-of-days (TOD) on some biochemical and hormonal responses after resistance training sessions.
METHODS: Ten trained subjects (22±2 years) performed, in randomized order, three resistance-training-sessions at 7 a.m., 1 p.m. and 5 p.m. Each training-session included six upper and lower body resistance exercises with 3×10 repetitions. Blood lactate (Lac), creatine kinase (CK), lactate dehydrogenase (LDH), cortisol (C) and testosterone (T) were collected at rest, 3 min and 48 h after each-session.
RESULTS: At rest, steroidal hormones were higher in the morning compared to the evening (P<0.01), whereas, no significant TOD effect on Lac, CK or LDH was observed. 3min after training, whatever the TOD, Lac, CK and T increased significantly (P<0.001). However, a significant decrease in C and a significant increase of T/C ratio were registered only after morning training. 3 min and even 48 h after training, the diurnal variations (i.e., morning to evening) of CK and C have been altered with higher early evening values of CK and lower one of C; whereas, T, Lac and LDH conserved their resting diurnal variation. Additionally, 48 h after the morning session, CK and T/C ratio remained elevated compared to the baseline levels.
CONCLUSIONS: In conclusion, resistance exercises soliciting both lower and upper limbs seems to alter the diurnal variation of CK and C, to enhance the morning anabolism/catabolism status and to produce more favorable environment for muscular adaptation up to 48 h post-training.

KEY WORDS: Creatine kinase - Biomarkers - Circadian rhythm - Resistance training