Influence of Tea Extract on Maximal Voluntary Knee Contraction Following Downhill Jogging

NCT07113405 | Recruiting

• 1 other identifier: 2025-01302
• Study Type: interventional
• Target: 60
• Locations: 1 country
• Sites: 1

Brief Summary

In this research project, we want to investigate whether the combined intake of proteins and tea extract has an influence on muscle regeneration compared to the sole intake of proteins or a placebo product. In the study, you will be randomly assigned to one of 3 groups. Neither the research group nor you will know which group you are assigned to. The study lasts 5 days for you as a participant. During these 5 days you will have to attend a total of 5 appointments in our laboratory. The groups differ only in the intake of the regeneration product, otherwise all measurements and appointments are identical. You will jog downhill for 30 minutes on the first day in order to strain your muscles. In order to be able to draw conclusions about the regeneration of your muscles, we will carry out the following measurements on all 5 days: Blood sampling at the fingertip, ultrasound of the thigh muscle, pain tolerance of the thigh muscle, strength tests of the thigh muscle, muscle function of the thigh muscle and jumping performance.

Conditions

Muscle Recovery

Keywords

Protein; muscle recovery; Tea extract; EIMD

Outcome Measures

Primary Outcomes (5)

• Change in maximum knee extension force immediately after training-induced muscle damage and 24, 48, 72, and 96 hours thereafter compared to baseline.

  The maximal force is measured in Nm while the participant is seated on an isokinetic device.

  5 days

• Change in jump performance immediately after training-induced muscle damage and 24, 48, 72, and 96 hours thereafter compared to baseline.

  The jump performance is measured in cm while the participant are performing counter movement jumps.

  5 days

• Change in perceived pain immediately after training-induced muscle damage and 24, 48, 72, and 96 hours thereafter compared to baseline.

  Perceived pain is measured in Pa while the participant is seated on the isokinetic device. The measurement point is on vastus medialis muscle.

  5 days

• Change in muscle thickness immediately after training-induced muscle damage and 24, 48, 72, and 96 hours thereafter compared to baseline.

  Muscle thickness is measured with b-mode ultrasound in mm while the participant is sitting on the isokinetic device. The measurement point is on the vastus medialis muscle.

  5 days

• Change in creatine kinase levels immediately after exercise-induced muscle damage and 24, 48, 72, and 96 hours thereafter compared to baseline.

  Creatine kinase is measured in U/L and determined using a capillary finger blood sample of 0.25 ml.

  5 days

Study Arms (3)

Protein and tea extract

EXPERIMENTAL

This group will receive a recovery drink containing protein and tea extract.

Dietary Supplement: Protein and tea extract

Protein

ACTIVE COMPARATOR

This group will receive a recovery drink containing protein without tea extract.

Dietary Supplement: Protein

Placebo

PLACEBO COMPARATOR

This group will receive a recovery drink containing a placebo product. The placebo product is a non-isoenergetic, non-protein, artificially flavoured liquid.

Dietary Supplement: Placebo

Interventions

Protein and tea extract DIETARY_SUPPLEMENT

Participants in this group will receive 4 times a recovery drink containing protein and tea extract.

Protein and tea extract

Protein DIETARY_SUPPLEMENT

Participants of this group will receive ten times a recovery drink containing only protein without tea extract.

Protein

Placebo DIETARY_SUPPLEMENT

Participants of this group will receive 10 times a placebo containing no protein nor tea extract.

Placebo

Eligibility Criteria

• Age: 18 Years - 40 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Signed written informed consent
• Aged between 18-40 years
• Healthy subjects

You may not qualify if:

• Any type of food allergy (e.g. nuts)
• Health-related problems according to the "Physical Activity Readiness Questionnaire (PAR-Q)
• Current injury of the lower extremities
• Serious clinical back pain or current back injuries
• Orthopedic disorders
• Cardiovascular diseases
• Current Intake of blood-thinning medication
• Current Intake of anti-inflammatory medication

Sponsors & Collaborators

• University of Fribourg: lead

Study Sites (1)

University of Fribourg

Fribourg, Canton of Fribourg, 1700, Switzerland

RECRUITING

Related Publications (7)

• Volpe-Fix AR, de Franca E, Silvestre JC, Thomatieli-Santos RV. The Use of Some Polyphenols in the Modulation of Muscle Damage and Inflammation Induced by Physical Exercise: A Review. Foods. 2023 Feb 21;12(5):916. doi: 10.3390/foods12050916.

  PMID: 36900433 RESULT

• Isaacs AW, Macaluso F, Smith C, Myburgh KH. C-Reactive Protein Is Elevated Only in High Creatine Kinase Responders to Muscle Damaging Exercise. Front Physiol. 2019 Feb 11;10:86. doi: 10.3389/fphys.2019.00086. eCollection 2019.

  PMID: 30804809 RESULT

• Hug F, Avrillon S, Del Vecchio A, Casolo A, Ibanez J, Nuccio S, Rossato J, Holobar A, Farina D. Analysis of motor unit spike trains estimated from high-density surface electromyography is highly reliable across operators. J Electromyogr Kinesiol. 2021 Jun;58:102548. doi: 10.1016/j.jelekin.2021.102548. Epub 2021 Mar 30.

  PMID: 33838590 RESULT

• Fischer AA. Pressure algometry over normal muscles. Standard values, validity and reproducibility of pressure threshold. Pain. 1987 Jul;30(1):115-126. doi: 10.1016/0304-3959(87)90089-3.

  PMID: 3614975 RESULT

• Del Vecchio A, Casolo A, Negro F, Scorcelletti M, Bazzucchi I, Enoka R, Felici F, Farina D. The increase in muscle force after 4 weeks of strength training is mediated by adaptations in motor unit recruitment and rate coding. J Physiol. 2019 Apr;597(7):1873-1887. doi: 10.1113/JP277250. Epub 2019 Feb 6.

  PMID: 30727028 RESULT

• Coratella G, Varesco G, Rozand V, Cuinet B, Sansoni V, Lombardi G, Vernillo G, Mourot L. Downhill running increases markers of muscle damage and impairs the maximal voluntary force production as well as the late phase of the rate of voluntary force development. Eur J Appl Physiol. 2024 Jun;124(6):1875-1883. doi: 10.1007/s00421-023-05412-z. Epub 2024 Jan 10.

  PMID: 38195943 RESULT

• Botter A, Vieira TM, Loram ID, Merletti R, Hodson-Tole EF. A novel system of electrodes transparent to ultrasound for simultaneous detection of myoelectric activity and B-mode ultrasound images of skeletal muscles. J Appl Physiol (1985). 2013 Oct 15;115(8):1203-14. doi: 10.1152/japplphysiol.00090.2013. Epub 2013 Aug 1.

  PMID: 23908313 RESULT

MeSH Terms

Interventions

Proteins; Tea

Intervention Hierarchy (Ancestors)

Amino Acids, Peptides, and Proteins; Plant Preparations; Biological Products; Complex Mixtures; Beverages; Diet, Food, and Nutrition; Physiological Phenomena; Food and Beverages

Central Study Contacts

Sven Egger, Dr.

CONTACT

+41 26 300 72 85; sven.egger@unifr.ch

Benedikt Lauber, PD Dr.

CONTACT

+41 26 300 72 86; benedikt.lauber@unifr.ch

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: PARTICIPANT, INVESTIGATOR
• Purpose: BASIC SCIENCE
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Model Details: randomized, double-blinded, placebo-controlled.

Study Record Dates

• First Submitted: July 25, 2025
• First Posted: August 8, 2025
• Study Start: December 1, 2025
• Primary Completion (Estimated): December 30, 2026
• Study Completion (Estimated): December 30, 2026
• Last Updated: May 4, 2026

Record last verified: 2026-05

Data Sharing

• IPD Sharing: Will not share

Locations

CH (1)