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Carbohydrate Availability and Running Performance in Professional Male Footballers

The Effect of Varying Carbohydrate Intake on Training Performance in Professional Football Players

Status
Completed
Phases
Unknown
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT07668726
Enrollment
17
Registered
2026-06-25
Start date
2026-04-01
Completion date
2026-05-01
Last updated
2026-06-25

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Carbohydrate Intake and Exercise Performance

Keywords

Exercise Performance, Football, Carbohydrate Intake

Brief summary

The goal of this clinical trial is to learn how different daily carbohydrate intakes affect training performance in professional male football players during a pre-season training week. The main questions it aims to answer are: * Does a higher carbohydrate intake affect how much high-speed running and sprinting players complete during football training? * Does a higher carbohydrate intake affect players' jumping performance, perceived effort, recovery, and daily readiness? Researchers will compare two carbohydrate intakes. In one condition, participants will consume a moderate-carbohydrate diet. In the other condition, participants will consume the same base diet plus carbohydrate drinks. The drinks will look and taste similar, but only one type will contain extra carbohydrate. Participants will complete both conditions during two pre-season training weeks. The order of the conditions will be randomized. This means participants will be assigned by chance to start with either the moderate-carbohydrate condition or the higher-carbohydrate condition. During the study, participants will: * Follow a standardized diet during each training week * Drink three study beverages per day during each condition * Take part in their regular team football training * Wear a global positioning system device during training to measure running activity * Complete countermovement jump tests during the training weeks * Report their perceived effort, recovery, and daily readiness This study will help researchers understand whether changing carbohydrate intake during a normal football training week affects training output and recovery-related measures in professional football players.

Detailed description

This study used a single-blind, placebo-controlled, randomized crossover design to examine the effects of different levels of daily carbohydrate availability during a pre-season training microcycle in professional male football players. The study was conducted in an applied professional football environment during two consecutive pre-season training weeks. Each participant completed both dietary conditions. The order of the two conditions was randomized and counterbalanced. The training schedule and overall training content were matched between the two intervention weeks as part of the club's regular training program. The two dietary conditions were designed to provide different daily carbohydrate intakes. In both conditions, participants followed a standardized food-based diet that provided 4 grams of carbohydrate per kilogram of body mass per day. In the higher-carbohydrate condition, participants also consumed three carbohydrate-containing study beverages per day, providing an additional 3 grams of carbohydrate per kilogram of body mass per day. This resulted in a total target intake of 7 grams of carbohydrate per kilogram of body mass per day. In the moderate-carbohydrate condition, participants consumed similar placebo beverages without added carbohydrate, resulting in a total target intake of 4 grams of carbohydrate per kilogram of body mass per day. The study beverages were prepared from water and an artificially sweetened concentrate. In the higher-carbohydrate condition, maltodextrin was added to the beverage. In the moderate-carbohydrate condition, no maltodextrin was added. Beverages were provided in non-transparent bottles to support participant blinding. Participants were not informed of the carbohydrate content of the study beverages. Dietary targets were individualized according to body mass. Breakfast and snacks were individualized according to participant preferences but standardized for carbohydrate content. Lunch was provided through the club's restaurant and adjusted to meet the carbohydrate target. Dinner targets were communicated using an image-based portion guide to support consistent carbohydrate intake outside the training facility. Participants were instructed to maintain their habitual protein and fat intake across both conditions. Adherence to supervised meals and beverages at the training facility was monitored by study staff. Evening beverages were distributed for home consumption and returned the following morning so that remaining contents could be inspected. Dietary intake outside the training facility was not fully controlled. External training load was monitored during football training sessions using a global positioning system device worn by each participant. The same device was used by each participant throughout the study to reduce measurement variation. The training monitoring system was used to quantify running and movement demands during the intervention period. Neuromuscular function was assessed using countermovement jump testing on repeated occasions during the two training weeks. Self-reported measures were collected to assess perceived exertion after training, perceived recovery before training, and daily readiness upon waking. The study was designed to compare the two carbohydrate conditions within the same participants while preserving the normal structure of a professional football training environment. This design allowed the researchers to examine whether changing carbohydrate availability during regular team training influenced training-related performance and recovery measures under applied conditions.

Interventions

DIETARY_SUPPLEMENTHigh-Carbohydrate Beverage

Participants consumed three daily maltodextrin-containing beverages in addition to a standardized food-based diet providing 4 grams of carbohydrate per kilogram of body mass per day. The beverages provided an additional 3 grams of carbohydrate per kilogram of body mass per day, resulting in a total target intake of 7 grams of carbohydrate per kilogram of body mass per day.

DIETARY_SUPPLEMENTplacebo beverage

Participants consumed three daily placebo beverages without added carbohydrate in addition to the same standardized food-based diet providing 4 grams of carbohydrate per kilogram of body mass per day. The total target intake was 4 grams of carbohydrate per kilogram of body mass per day.

Sponsors

Göteborg University
Lead SponsorOTHER

Study design

Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
OTHER
Masking
SINGLE (Subject)

Eligibility

Sex/Gender
MALE
Age
18 Years to No maximum
Healthy volunteers
Yes

Inclusion criteria

* Professional male football player * Outfield player * Member of the recruited professional football team * Available to take part in the pre-season training period * Able to follow the study diet and beverage protocol * Able to wear a global positioning system device during training * Provided written informed consent

Exclusion criteria

* Goalkeeper * Injured at the start of the study period * Expected to leave the team on loan during the study period * Unable to complete both dietary conditions

Design outcomes

Primary

MeasureTime frameDescription
High-Speed Running DistanceDuring each football training session in each of the two 1-week intervention periodsDistance covered at speeds \>19.8 km·h-¹ during football training sessions, measured in meters using a global positioning system device.
Number of SprintsDuring each football training session in each of the two 1-week intervention periodsNumber of sprint efforts performed during football training sessions, measured using a global positioning system device.
Sprint DistanceDuring each football training session in each of the two 1-week intervention periodsDistance covered at speeds \>25.2 km·h-¹ during football training sessions, measured in meters using a global positioning system device.

Secondary

MeasureTime frameDescription
Total Distance CoveredDuring each football training session in each of the two 1-week intervention periodsTotal distance covered during football training sessions, measured in meters using a global positioning system device.
High Metabolic Load DistanceDuring each football training session in each of the two 1-week intervention periodsDistance covered at high metabolic load \>25 W·kg-¹ during football training sessions, measured in meters using a global positioning system device.
Acceleration DistanceDuring each football training session in each of the two 1-week intervention periodsDistance covered during accelerations \>3 m·s-² during football training sessions, measured in meters using a global positioning system device.
Number of AccelerationsDuring each football training session in each of the two 1-week intervention periodsNumber of acceleration events \>3 m·s-² during football training sessions, measured using a global positioning system device.
Deceleration DistanceDuring each football training session in each of the two 1-week intervention periodsDistance covered during decelerations \<-3 m·s-² during football training sessions, measured in meters using a global positioning system device.
Number of DecelerationsDuring each football training session in each of the two 1-week intervention periodsNumber of deceleration events \<-3 m·s-² during football training sessions, measured using a global positioning system device.
Countermovement Jump HeightThree times during each 1-week intervention period: baseline, mid-week, and end-weekCountermovement jump height, measured in centimeters using \[force platform Hawkin Dynamics, Gen 5, USA\].
Session Rating of Perceived ExertionAfter each football training session in each of the two 1-week intervention periodsRating of perceived exertion after each football training session, measured using the Borg CR10 scale.
Perceived RecoveryBefore each football training session in each of the two 1-week intervention periodsPerceived recovery assessed before football training sessions using single-item 0 to 10 scale, where 0 indicates complete exhaustion and 10 full recovery
Perceived ReadinessDaily upon waking during each of the two 1-week intervention periodsPerceived readiness assessed using Hooper Index.

Countries

Sweden

Contacts

PRINCIPAL_INVESTIGATORStefan Pettersson, PhD, Associate Professor

Department of Food and Nutrition, and Sport Science, Göteborgs universitet, Gothenburg, Sweden

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Jun 26, 2026