Repetition Prescription Approaches Delivered Via Videoconferencing

  • participants needed
  • sponsor
    Tel Aviv University
Updated on 20 September 2021
Hadar Schwartz
Primary Contact
Tel Aviv University (9.7 mi away) Contact


A randomized controlled trial comparing between two approaches of prescribing repetition-numbers in resistance training (RT) sessions on psychological, physiological, and performance outcomes. Sixty healthy and sedentary adults (age range: 18-45) will be randomly allocated to either the "predetermined" or "self-selected" groups. The groups will differ in the amount of choice they will be able to make concerning the resistance of each exercise and the number of repetitions they complete (see detailed description). Both groups will complete two sessions per week composed of body weight and resistance band exercises, lasting 45 minutes for eight weeks. The sessions will be delivered live by a certified instructor using a videoconferencing platform.

The primary aim of this study is:

Compare between the "predetermined" and the "self-selected" repetition prescription approaches on psychological, physiological, and performance outcomes in a cohort of 60 healthy and sedentary adults (age range: 18-45) over an eight-week period of live, videoconferencing RT sessions.

The secondary aim is:

Determine the influence of live, videoconferencing group RT sessions on psychological, physiological, and performance outcomes across groups.



Providing trainees with more choices in exercise sessions is an autonomy supportive process which can lead to a more enjoyable experience, greater adherence to the training program and preferable performance outcomes. We will compare between two approaches to prescribing repetition-numbers in resistance training sessions- the "predetermined" and the "self-selected", based on the amount of choice trainees receive while training. Sixty healthy and sedentary adults (age range: 18-45) will train bi-weekly for 45 minutes using resistance bands in a live, videoconferencing group setting.

Intervention details:

The intervention will last eight weeks and include bi-weekly, 45-minute online sessions instructed by two alternating experienced instructors. Each session will include an introduction and setup (5-minutes), warm-up (5-minutes), body-weight and resistance band exercises (30-minutes) and cool down (5-minutes). We will upload the study protocol to an external server for more details.

Both groups will follow the exact same exercise program with one key difference: participants in the "predetermined" group will be instructed to complete 10 repetitions per set and exercise, while aiming to reach a rating of perceived exertion (RPE) of 7/10 by the 10th repetition. This means that participants will need to select and adjust the resistance of each exercise (e.g., band's resistance) to achieve this goal. Conversely, in the "self-selected" group, participants will choose the initial resistance in view of their preferences, and complete as many repetitions as they wish in order to reach the same target RPE of 7/10. Note that while the initial resistance, and thus, the number of repetitions is expected to differ between group, both are matched for perception of effort.

Recruitment and procedures:

Participants will be recruited via social media (i.e., Facebook Inc., Menlo Park, CA, USA). Each candidate will be screened for initial eligibility. After screening participants will be block-randomized to the "predetermined" of the "self-selected" groups, matched for age and gender. Participants will be blind to their allocation (see concealment section). Prior to visiting the exercise laboratory at Tel Aviv University for the testing session, participants will receive written materials regarding the exercise sessions, testing procedures, and the use of the Rating of Perceived Exertion (RPE) scale (0-10), and a video demonstrating the implementation of RPE in practice. All participants that are part of a given group will be required to complete the first testing session within a maximum of one week before the program begins, and the follow up testing session within a maximum of one week after the program ends. Practically, one group will begin and end all procedures (i.e., initial testing, eight-weeks program, follow up testing) one week before the other group. The order of which group will begin first will be randomly decided by a coin flip.

The initial testing session will include the following steps:

  1. Sign an informed consent form.
  2. Fill out the Basic Regulations in Exercise Questionnaire (BREQ).
  3. Body composition analysis (see outcome measures section).
  4. RPE terminology verification based on the videos and written materials delivered in advance.
  5. Performance tests (see outcome measures section).
  6. Practice how to use the resistance band (see below) and set up terminology to be used during the sessions (e.g. "open loop", "more tension").

That same order will be kept on the final tests (excluding the informed consent), which will also be conducted at the same place, at the same hour-window, and by the same experimenter.

Home-based equipment:

Participants will receive one elastic band (NT loops, purchased from: ( as they are affordable, accessible and allow exercising in a controlled, safe manner. When practicing with an elastic band, changing grip width, or rubber stiffness allows the trainee to achieve greater or lesser resistance.

Videoconferencing platform:

RT sessions will be delivered using "Zoom video communications" (San-Jose, CA, USA) due to its popularity and user-friendly interface. Additionally, a WhatsApp group chat (Facebook Inc., Menlo Park, CA, USA) will be created for each group to deliver updates and reminders. A technical assistant from the research team will be available during the live broadcast.

Sample size:

This sample size is based on our recruitment abilities and resources and based on our previous experience with this type of intervention. A sample size of 30 participants per group is considered large in exercise science research with both statistically and practically significant effects often detected. We also expect for future meta-analyses to take place and for this work to be included. Thus, even if this study is currently under-powered for small effects, it may add valuable data to the field of exercise science.

Condition Health behavior
Treatment RPE-based load and repetition number selection, Predetermined load and number of repetitions
Clinical Study IdentifierNCT04895865
SponsorTel Aviv University
Last Modified on20 September 2021

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