Myo-Reps Versus Traditional Sets for Muscle Strength, Fat-Free Mass, and Time Efficiency

Myo-Reps Versus Traditional Sets for Muscle Strength, Fat-Free Mass, and Time Efficiency: a Randomized Controlled Trial

This study compared two ways of doing strength training in healthy adults. The first, called Myo-Reps, is a time-saving method: one hard first set of 8-15 repetitions, followed by three short "mini-sets" of 3-5 repetitions with only 10-20 seconds of rest in between. The second is traditional training: three sets of 8-15 repetitions with 1-3 minutes of rest between sets.

Thirty-four adults were randomly assigned, by chance, to one of the two groups. For nine weeks everyone trained twice a week, under supervision, doing full-body workouts on 10 gym machines. The researchers measured how much stronger people became on each exercise, how much their fat-free mass (muscle and other lean tissue) changed, how hard the sessions felt, how much weight and how many repetitions were lifted, and how long the sessions took.

The aim was to find out whether the shorter Myo-Reps workouts can build strength and fat-free mass as well as traditional training.

Study Overview

• Status: Completed
• Conditions: Resistance Exercise; Muscle Strength Development
• Intervention / Treatment: Other: Myo-Reps resistance training; Other: Traditional three-set resistance training

Detailed Description

Rationale: Lack of time is a common barrier to resistance training. The study tested two competing predictions. If total volume load (load × repetitions) is the main driver of adaptation, traditional three-set training should give greater improvements. If repetitions performed close to failure matter more, Myo-Reps could give similar or greater improvements despite less volume and shorter sessions.

Design: Parallel-group randomized trial in healthy adults, 1:1 allocation, stratified by gender and age, using a central web-based randomization system run by an independent trial unit; allocation was concealed until enrolment. All sessions were directly supervised, and load progression rules were identical in both groups. Week 1: familiarization and baseline body composition. Week 2: baseline strength testing. Weeks 3-11: training. Week 12: repeat testing.

Analysis: No sample-size calculation was performed (convenience sample). Strength comparisons are exploratory and analysed separately for each exercise.

Registration note: This record was registered retrospectively, after data collection was completed. Outcomes are described as defined in the manuscript submitted for publication.

• Study Type: Interventional
• Enrollment (Actual): 34
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Norway
  • Trøndelag
    • Trondheim, Trøndelag, Norway, 7030
      • Sit Trening HelgasetrSit

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 65 years (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• 18-65 years
• Generally good health
• No medical contraindications for heavy resistance training

Exclusion Criteria:

• highly advanced trainees
• pregnancy

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Myo-Rep; Nine weeks (weeks 3-11) of two supervised full-body sessions per week on 10 resistance-training machines. For each exercise: one activation set of 8-15 repetitions close to failure, followed by three mini-sets of 3-5 repetitions with the same load, separated by 10-20 seconds of rest. Load progression criteria were identical to the traditional training group.	Other: Myo-Reps resistance training; Supervised full-body machine-based resistance training, twice weekly for nine weeks. Each exercise: one activation set of 8-15 repetitions close to failure, then three mini-sets of 3-5 repetitions with the same load and 10-20 seconds of rest between sets.
Active Comparator: Traditional three-set training; Nine weeks (weeks 3-11) of two supervised full-body sessions per week on the same 10 resistance-training machines. For each exercise: three sets of 8-15 repetitions separated by 1-3 minutes of rest. Load progression criteria were identical to the Myo-Reps group.	Other: Traditional three-set resistance training; Supervised full-body machine-based resistance training, twice weekly for nine weeks, using the same 10 exercises. Each exercise: three sets of 8-15 repetitions with 1-3 minutes of rest between sets.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in exercise-specific muscular strength (estimated one-repetition maximum, e1RM) across 10 machine exercises	e1RM was derived from 3-10 repetition-maximum tests (Epley equation) for each of the 10 trained machine exercises. Each exercise was analysed separately, and the between-group difference in change from baseline to post-intervention is the outcome.	Baseline (week 2) to post-intervention (week 12)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in fat-free mass	Measured by bioelectrical impedance (InBody 770).	Baseline (week 1) to post-intervention (week 12)
Session duration	Time taken to complete a training session, averaged per participant.	Training weeks 3-11
Weekly volume load	Load × repetitions, summed across exercises and averaged per week.	Training weeks 3-11
Repetitions close to failure	Estimated number of repetitions performed close to muscular failure during training.	raining weeks 3-11
Session rating of perceived exertion (session RPE)	Participant-rated exertion for each training session.	Training weeks 3-11

Collaborators and Investigators

• Sponsor: Norwegian University of Science and Technology
• Investigators: Principal Investigator: Marius S Fimland, Phd, NTNU - Norwegian University of Science and Technology

Study record dates

Study Major Dates

• Study Start (Actual): August 26, 2025
• Primary Completion (Actual): December 3, 2025
• Study Completion (Actual): December 3, 2025

Study Registration Dates

• First Submitted: October 26, 2026
• First Submitted That Met QC Criteria: October 30, 2026
• First Posted (Actual): November 3, 2026

Study Record Updates

• Last Update Posted (Actual): November 3, 2026
• Last Update Submitted That Met QC Criteria: October 30, 2026
• Last Verified: October 1, 2026

More Information

Terms related to this study

• Keywords: muscle strength; strength training; resistance training; time efficiency; fat-free mass; training volume; Myo-Reps; rest-pause training
• Other Study ID Numbers: SIKT ID: 187305

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES

IPD Plan Description

De-identified individual participant data underlying the published results will be made available to qualified researchers on reasonable request to the corresponding author, after publication of the main article. Requests should include a brief research proposal.

IPD Sharing Time Frame

Data will be available beginning after publication of the main article and for at least 5 years thereafter.

IPD Sharing Access Criteria

De-identified individual participant data will be shared with qualified researchers on reasonable request to the corresponding author (Philip Meisterl, NTNU), who will review each request. Requesters should provide a short research proposal. Data are shared only for scientific research purposes, consistent with participants' consent and Norwegian data protection regulations (GDPR). Data will be sent securely by email or a secure file-transfer link.

Drug and device information, study documents

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