Protein Intake and Exercise-induced Muscle Damage (PROMO)

Comparing the Effects of Three PROtein-enhancement Strategies on Exercise-induced Muscle Damage in Older Adults

The goal of this clinical trial is to test the effect of different protein-enhancement strategies versus carbohydrate control on exercise-induced muscle damage in physically active older adults. The main question it aims to answer is:

What is the effect of three different protein-enhancement strategies (whey protein (WP), mixed plant-based protein (MPP), and use of protein-rich food products (PFP) on exercise-induced muscle damage in older adults compared to isocaloric carbohydrate control?

Participants will:

• Use a protein-enhancement strategy (WP, MPP or PFP) or carbohydrate control for a total of 5 weeks;
• Participate in a single walking bound (30/40/50 km) two weeks after the start of the study;
• Participate in a consecutive walking bound (4 days of 30/40/50 km) in the last week of the study period;
• Complete different questionnaires and give blood samples to test for muscle damage.

Study Overview

• Status: Completed
• Conditions: Sarcopenia
• Intervention / Treatment: Dietary supplement: whey protein supplement; Dietary supplement: mixed plant-based protein supplement; Other: e-health application; Dietary supplement: isocaloric carbohydrate control

• Study Type: Interventional
• Enrollment (Actual): 199
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Netherlands
  • Gelderland
    • Nijmegen, Gelderland, Netherlands, 6525GC
      • Radboudumc

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• 60 years or older
• Registered for the Nijmegen Four Days Marches (i.e., able to walk 30-50 km/day)
• A habitual protein intake <1.0 g/kg/d based on the protein 55+ (PRO55+) screening tool
• Able to understand and perform the study procedures
• Able to use a mobile device

Exclusion Criteria:

• Allergic or sensitive for milk proteins, or lactose intolerant
• Diagnosed type I or type II diabetes mellitus
• Diagnosed intestinal diseases influencing the uptake of protein (i.e., active inflammatory bowel disease, Crohn's disease)
• Consumption of other freely available protein supplements during the study period.
• If the subject intends to perform additional exercise bouts that cause muscle damage in the 4 days before the single- and multiple exercise bouts.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

4

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: animal-based protein (WP); Supplements and control (MPP, WP, CON) will be consumed as a drink or in a recipe for five subsequent weeks (30 g/day); four weeks preload and one week during the Four Days Marches. With this amount, we aim to increase the protein intake from <1.0g/kg/bw/d to >1.2g/kg/bw/d. Participants are allowed to dissolve the powder in a liquid of choice: we will provide several examples to the participants during the instructions.	Dietary supplement: whey protein supplement; Daily dosage of the supplements will be 30 gram, preferably consumed in the morning and post-exercise or prior to sleep.
Experimental: plant-based protein (MPP); Supplements and control (MPP, WP, CON) will be consumed as a drink or in a recipe for five subsequent weeks (30 g/day); four weeks preload and one week during the Four Days Marches. With this amount, we aim to increase the protein intake from <1.0g/kg/bw/d to >1.2g/kg/bw/d. Participants are allowed to dissolve the powder in a liquid of choice: we will provide several examples to the participants during the instructions.	Dietary supplement: mixed plant-based protein supplement; Daily dosage of the supplements will be 30 gram, preferably consumed in the morning and post-exercise or prior to sleep.
Experimental: protein-rich food products (PFP); PFP will receive digitally supported dietary intake counselling, with a focus on the use of protein-enriched food products in order to increase protein intake up to >1.2 k/kg/bw/d.	Other: e-health application; Daily use of an e-health application with dietary intake counselling to increase protein intake. The overall goal of these advices is to increase protein intake from <1.0g/kg/bw/d to >1.2g/kg/bw/d which is approximately 30 grams of additional protein per day (similar to the other arms of the intervention).
Active Comparator: control (CON); Supplements and control (MPP, WP, CON) will be consumed as a drink or in a recipe for five subsequent weeks (30 g/day); four weeks preload and one week during the Four Days Marches. With this amount, we aim to increase the protein intake from <1.0g/kg/bw/d to >1.2g/kg/bw/d. Participants are allowed to dissolve the powder in a liquid of choice: we will provide several examples to the participants during the instructions.	Dietary supplement: isocaloric carbohydrate control; Daily dosage of the supplements will be 30 gram, preferably consumed in the morning and post-exercise or prior to sleep.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
serum creatine kinase (CK) levels	Exercise-induced muscle damage. Non-fasted venous blood samples will be drawn from the antecubital vein at each pre-exercise and post-exercise visit. Based on previous research it is expected that time-dependent exercise-induced increase in creatine kinase (CK) levels are significantly different between protein groups and control, but not within protein groups. Multiple peak post-exercise CK concentrations (several hours to up to 48h post exercise) will be compared to pre-exercise CK levels to compare the effect of different protein enhancing strategies versus carbohydrate control.	Measured 8 times in total. Once pre-single exercise, two times post-single exercise (within 2h after and around 24h after) and 2 weeks later: once pre-multiple day exercise and four times post-multiple day exercise (within 2h post-exercise)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
serum lactate dehydrogenase (LDH) levels	(Muscle) cell damage. Non-fasted venous blood samples will be drawn from the antecubital vein at each pre-exercise and post-exercise visit.	Measured 8 times in total. Once pre-single exercise, two times post-single exercise (within 2h after and around 24h after) and 2 weeks later: once pre-multiple day exercise and four times post-multiple day exercise (within 2h post-exercise)
muscle soreness	Muscle soreness is measured via the the Numeric Pain Scale (from 0 to 10, a higher score means more muscle soreness.	Measured 8 times in total. Once pre-single exercise, two times post-single exercise (within 2h after and around 24h after) and 2 weeks later: once pre-multiple day exercise and four times post-multiple day exercise (within 2h post-exercise)
muscle function	Maximal handgrip strength is measured to the nearest 0.5 kg using a hand dynamometer. The participants is seated in a chair with the shoulders adducted and neutrally rotated and elbow flexed at 90o. Three consecutive measurements of handgrip strength will be recorded.	Measured 8 times in total. Once pre-single exercise, two times post-single exercise (within 2h after and around 24h after) and 2 weeks later: once pre-multiple day exercise and four times post-multiple day exercise (within 2h post-exercise)

Collaborators and Investigators

• Sponsor: Radboud University Medical Center
• Collaborators: Cosun
• Investigators: Principal Investigator: Maria Hopman, prof. dr., Radboud University Medical Center

Study record dates

Study Major Dates

• Study Start (Actual): June 10, 2024
• Primary Completion (Actual): July 19, 2024
• Study Completion (Actual): July 31, 2025

Study Registration Dates

• First Submitted: December 21, 2023
• First Submitted That Met QC Criteria: January 29, 2024
• First Posted (Actual): February 1, 2024

Study Record Updates

• Last Update Posted (Actual): November 17, 2025
• Last Update Submitted That Met QC Criteria: November 14, 2025
• Last Verified: October 1, 2025

More Information

Terms related to this study

• Keywords: e-health; Supplements; Nutritional intervention; Muscle damage; Protein intake
• Additional Relevant MeSH Terms: Neurologic Manifestations; Nervous System Diseases; Neuromuscular Manifestations; Pathological Conditions, Anatomical; Muscular Atrophy; Atrophy; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Sarcopenia
• Other Study ID Numbers: 86007.091.23

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: Individual Participant Data (IPD) will be shared with researchers within the department of Medical Biosciences of the Radboud University Medical Center (Radboudumc). The department has a database of data from the past 15 years of Four Day Marches data. This research data will be added to the database. Data may be shared with other researchers upon request.
• IPD Sharing Time Frame: The data will become available after completion of the study and will be available for at least 15 years.
• IPD Sharing Access Criteria: IPD will be shared with researchers within the department of Medical Biosciences of the Radboudumc. Data may be shared with other researchers upon request.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP; ICF; ANALYTIC_CODE; CSR

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No