Muscle Glycogen Synthesis When Caffeine and Protein is Co-Ingested With Carbohydrates

This study has been completed.
Information provided by (Responsible Party):
Milou Beelen, Maastricht University Medical Center Identifier:
First received: September 10, 2009
Last updated: April 13, 2015
Last verified: April 2015

The aim of the present study is to investigate the effect of added protein+leucine or caffeine to 1.2 g/kg/h CHO on the rate of post-exercise muscle glycogen re-synthesis in healthy, recreational athletes.

The investigators hypothesize that both interventions (the addition of caffeine or protein+leucine) will lead to higher glycogen re-synthesis compared to the ingestion of CHO only, and that the co-ingestion of protein and leucine will result in the highest muscle glycogen synthesis rates.

Condition Intervention
Exercise Recovery
Dietary Supplement: Carbohydrate
Dietary Supplement: Carbohydrate and protein ingestion
Dietary Supplement: Carbohydrate and caffeine ingestion

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Double Blind (Subject, Investigator)
Primary Purpose: Basic Science
Official Title: The Effect of Caffeine or Protein Co-ingestion With Carbohydrate on Post-exercise Muscle Glycogen Synthesis Rate.

Resource links provided by NLM:

Further study details as provided by Maastricht University Medical Center:

Primary Outcome Measures:
  • Muscle glycogen synthesis rates [ Time Frame: 6 hours ] [ Designated as safety issue: No ]

Secondary Outcome Measures:
  • Glycogen synthase activity, plasma glucose, insulin, free fatty acids and epinephrine responses [ Time Frame: 6 hours ] [ Designated as safety issue: No ]

Enrollment: 14
Study Start Date: February 2009
Study Completion Date: September 2009
Primary Completion Date: September 2009 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: 1
Carbohydrate ingestion
Dietary Supplement: Carbohydrate
1.2 g/kg/h
Experimental: 2
Carbohydrate and protein ingestion
Dietary Supplement: Carbohydrate and protein ingestion
1.2 g/kg/h carbohydrate plus 0.4 g/kg/h protein
Experimental: 3
Carbohydrate and caffeine ingestion
Dietary Supplement: Carbohydrate and caffeine ingestion
1.2 g/kg/h carbohydrate and 1.67 g/kg/h caffeine


Ages Eligible for Study:   18 Years to 35 Years
Genders Eligible for Study:   Male
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  • male cyclists
  • healthy
  • BMI < 25

Exclusion Criteria:

  • female
  • use of medication
  • non cycling
  • BMI > 25
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its identifier: NCT00975390

Maastricht University
Maastricht, Netherlands
Sponsors and Collaborators
Maastricht University Medical Center
  More Information

No publications provided

Responsible Party: Milou Beelen, Dr., Maastricht University Medical Center Identifier: NCT00975390     History of Changes
Other Study ID Numbers: 08-3-066
Study First Received: September 10, 2009
Last Updated: April 13, 2015
Health Authority: Netherlands: Medical Ethics Review Committee (METC)

Keywords provided by Maastricht University Medical Center:
Post exercise muscle glycogen synthesis
Sports nutrition

Additional relevant MeSH terms:
Central Nervous System Agents
Central Nervous System Stimulants
Enzyme Inhibitors
Molecular Mechanisms of Pharmacological Action
Neurotransmitter Agents
Pharmacologic Actions
Phosphodiesterase Inhibitors
Physiological Effects of Drugs
Purinergic Agents
Purinergic Antagonists
Purinergic P1 Receptor Antagonists
Therapeutic Uses processed this record on November 25, 2015