NAC Supplementation and Soccer Specific Performance

Not Applicable

Completed

• Conditions: Skeletal Muscle Damage; Antioxidant Status; Exercise-induced Aseptic Inflammation; Skeletal Muscle Performance
• Interventions: Dietary Supplement: N-acetylcysteine; Dietary Supplement: Placebo

• Registration Number: NCT04523675
• Lead Sponsor: University of Thessaly

Brief Summary

In this investigation the investigators utilized NAC supplementation to boost GSH availability during an one-week-microcycle consisting of three soccer games, in order to test the hypotheses that: i) antioxidant supplementation may enhance the recovery of performance and physiological stress variables following multiple match-plays and ii) redox status perturbations are critical in regulating the inflammatory response and repair in skeletal muscle, following repetitive exercise-induced muscle injuries.

Detailed Description

After exercise-induced muscle microtrauma the thiol/disulfide couple of reduced (GSH) and oxidized glutathione (GSSG) is a key regulator of important transcriptional pathways that control the inflammatory response and recovery of skeletal muscle.

The objective was to examine how thiol-based antioxidant supplementation affects the muscle damage, oxidative stress, inflammatory and immune responses, as well as the level of post-game fatigue and muscle's recovery kinetics in response to three soccer games within a week. Participants were randomly assigned to one of four groups: i) Experimental-NAC \[EXP-NAC, N=10, participated in daily training sessions and three games and received NAC (20 mg/kg/day)\], ii) Experimental-Placebo (EXP-Pla, N=10, participated in daily training sessions and three games and received Placebo), iii) Control-NAC \[CON-NAC, N=10, participated in daily training sessions only and received NAC(20 mg/kg/day)\] and iv) Control-Placebo (CON-Pla, N=10, participated in daily training sessions only and received Placebo). Blood samples were collected at baseline, post-games and daily during recovery. Performance was assessed at baseline and daily during recovery.

Study Timeline

• Study Start: 2016-04
• Primary Completion: 2016-07
• Study Completion: 2016-12
• Study First Submitted: 2020-06-22
• Status Verified: 2020-08
• Study First Submitted QC: 2020-08-20
• Last Update Submitted: 2020-08-20
• Study First Posted: 2020-08-21
• Last Update Posted: 2020-08-21

Recruitment & Eligibility

• Status: COMPLETED
• Sex: Male
• Target Recruitment: 40

Inclusion Criteria

• Participation at elite level (top three division leagues) of soccer competition for at least five years
• Abstained from consumption of performance-enhancing supplements, antioxidant supplements and medications (for at least 6 months before and during the study)
• Participation in at least six two-hour training sessions and one match per week
• Non-smokers

Exclusion Criteria

• A known NAC intolerance or allergy
• A recent febrile illness
• History of muscle lesion
• Lower limb trauma
• Metabolic diseases

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
CON-NAC	N-acetylcysteine	Participated in daily training sessions only and supplemented daily with N-acetylcysteine, orally in three daily dosages (morning-midday-evening),for seven consecutive days.
EXP-NAC	N-acetylcysteine	Participated in daily training sessions and three games, and supplemented daily with N-acetylcysteine, orally in three daily dosages (morning-midday-evening),for seven consecutive days.
EXP-Pla	Placebo	Participated in daily training sessions and three games, and supplemented daily with Placebo, orally in three daily dosages (morning-midday-evening), for seven consecutive days.
CON-Pla	Placebo	Participated in daily training sessions only and supplemented daily with Placebo, orally in three daily dosages (morning-midday-evening), for seven consecutive days.

Primary Outcome Measures

Name	Time	Method
Change in total antioxidant capacity in serum	At baseline and daily throughout the study, up to 11 days
Change in protein carbonyls in serum	At baseline and daily throughout the study, up to 11 days
Change in thiobarbituric acid reactive substances in serum	At baseline and daily throughout the study, up to 11 days
Change in reduced glutathione in red blood cells	At baseline and daily throughout the study, up to 11 days
Change in oxidized glutathione in red blood cells	At baseline and daily throughout the study, up to 11 days
Change in creatine kinase in activity in plasma	At baseline and daily throughout the study, up to 11 days
Change in white blood cell count in blood	At baseline and daily throughout the study, up to 11 days
Change in repeated sprint ability	At baseline and daily throughout the study, up to 11 days	Players' repeated sprint ability was assessed via a repeared sprint test. Each player performed 5 x 30 meters sprints interspersed by 25 seconds of active recovery. Sprint time was recorded by using infrared photoelectrical gates.
Change in high intensity running during the game	During games 1, 2 and 3	High intensity running (i.e. \> 14km/h) during the games was monitored by utilizing high time-resolution GPS devices.

Secondary Outcome Measures

Name	Time	Method
Change in blood lactate concentration during the game	During games 1, 2 and 3
Change in average heart rate during the game	During games 1, 2 and 3

Trial Locations

Locations (1)

Exercise Biochemistry Laboratory, School of Physical Education & Sports Sciences, University of Thessaly; 🇬🇷 Tríkala, Greece