Reference Values for the One Repetition Maximum Test of Knee Extensors for Brazilians.

October 17, 2024 updated by: Fabio Pitta, PhD, Universidade Estadual de Londrina

Reference Values for the One Repetition Maximum Test (1RM) of Knee Extensors for Brazilians.

Muscle strength is important for health and can affect how well people live, even increasing the risk of death in adults and older people. The one-repetition maximum (1RM) test is relatively easy compared to other tests and is commonly used to measure muscle strength in various groups, including healthy individuals and those with chronic diseases. It assists in prescribing resistance training and understanding training results. Knee extensors, especially the quadriceps femoris, are often studied because they play a key role in standing and walking. However, there are no standard reference values or equations for measuring knee extensors using the 1RM test. The existing methods rely on the evaluator's judgment, making them hard to replicate and standardize. The goal of this study is to provide reference equations and values for the 1RM of knee extensors and to establish a standardized methodology for the test.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Detailed Description

The project consists of two phases: in order to develop the final standardized 1RM protocol, a pilot study (phase 1) will be conducted to identify the best objective load to start the 1RM attempts. The protocol will then be defined according to the results of the pilot study, and the main study (phase 2) will be initiated using this protocol.

The one-repetition maximum test (1RM) will be conducted using a leg extension machine (MacSport, Sigma). This test aims to determine the maximum weight that can be lifted in a single movement by the tested muscle group (in this study, knee extensors) through its full range of motion and without compensatory movements. The knees should be aligned with the axis of the equipment (adjust the backrest if necessary), and hands should firmly grip the handles. The equipment will be set so that individuals start the knee extension from a 90 degree flexion and extend until reaching a 0 degree flexion. Standardized verbal encouragement will be given during the tests.

All recruited individuals, both those participating in the pilot study (phase 1) and those in the main study (phase 2), will be evaluated at two different moments. In the first evaluation (pilot study test 1, or pilot study T1), participants will be assessed for anthropometric data, presence of comorbidities, self-reported regular physical activity, cognitive screening and knee extensor muscle strength using the 1RM test, following the protocol proposed by the authors (details below). Specifically for the pilot study, which is a methodological study aimed at identifying the best initial load for the first 1RM attempt, three initial load options based on body weight (40%, 60%, and 80% of body weight) will be randomly assigned via envelopes. The pilot study will include 72 individuals in total, distributed across six age groups with an average interval of ten years (i.e., 18-29, 30-39, 40-49, 50-59, 60-69 and 70-80 years). Each age group will have 12 participants, with four performing the first 1RM attempt at 40% of body weight (two men and two women), another four at 60% of body weight (two men and two women), and the remaining four at 80% of body weight (two men and two women). This way, participants will be evenly distributed among age groups, gender and percentage of body weight for the initial 1RM attempt. In the assessment of the pilot study (pilot study T2), 48-72 hours after the first assessment pilot study T1, individuals will be re-evaluated for knee extensor strength (following the same protocol and the same percentage of body weight as in pilot study T1) to investigate the reproducibility and familiarization (e.g., learning affect) of the test.

The porposed protocol for the pilot study will follow this sequence: (1) warm-up with a set of 10 repetitions with a light load (20% of body weight); (2) two minutes of rest; (3) the frist attempt will be with the percentage of body weight randomly chosen before the start of the pilot (i.e., 40%, 60% or 80% of body weight); (4) the load progression will be based on the Likert scale of difficulty from 1 to 5 (1-Very easy, 2-Easy, 3-Moderate, 4-Very difficult, and 5-Extremely difficult); responses from 1 to 3 will have an increment of 20% of the last load, and responses from 4 to 5 will have an increment of 10% of the last load. Individuals will have two minutes of rest between each progression; (5) if the attempt is unsuccessful, the load should be decreased by 5% or 10%; upon success, this will be the 1RM value, and upon failure, the 1RM will be the last value successfully lifted; (6) the 1RM value should ideally be obtained in 4 to 6 attempts, provided that the last attempt is not the highest value. As mentioned earlier, after 48-72 hours, individuals will perform the pilot study T2 following the same protocol and initial load drawn in pilot study T1. The best initial load for the 1RM test will be the one that allows reaching the highest 1RM value in the fewest attempts in the best tests conducted in pilot study T1 and pilot study T2, as long as they fall within the range of 4 to 6 attempts.

After the completion of the pilot study with the result of the best initial load for the 1RM test, the main study will begin and follow the same protocol previously proposed. However, it will use the best percentage of body weight identified as the ideal initial load in the pilot study during both main study tests (main study T1 and main study T2). In both the pilot and main studies, the same evaluator should perform the test in both T1 and T2, allowing for the analysis of intra-evaluator reproducibility and avoiding potential inter-evaluator bias. The 1RM value used for analysis will be the highest value obtained from the evaluations in main study T1 and main study T2.

The sample size will be calculated based on the pilot study. The variable used for the calculation will be knee extensor strength, as this is the main outcome of the study. A power of 80% and an alpha of 0.05 will be adopted.

Microsoft Excel 2010 (Microsoft, USA) and SPSS 21.0 version (IBM, USA) will be used for data tabulation and statistical analysis, respectively. The Shapiro-Wilk test will be used for the analysis of normality in data distribution. Data with normal distribution will be described as mean ± standard deviation and statistically treated with parametric tests, whereas data with non-normal distribution will be described as median [interquartile range 25-75%] and statistically treated with non-parametric tests. To identify the best initial load for the 1RM test in the pilot study and to compare different age groups, one-way ANOVA or Kruskal-Wallis test with Dunn's post hoc test will be used when necessary. Pearson or Spearman coefficients will be used to identify simple correlations between the 1RM test and anthropometric variables, while multiple linear regression analysis will be used to establish reference equations. A value of P<0.05 will be adopted as statistical significance, except for the multiple linear regression model where variables showing a correlation with 1RM of knee extensors up to P<0.20 will be included in the model.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Observational

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
72

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

  • Brazil
    • Paraná
      • Londrina, Paraná, Brazil, 86038-350
        • Recruiting
        • Health Sciences Center of the State University of Londrina
        • Contact:

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Sampling Method

Non-Probability Sample

Study Population

Apparently healthy individuals from the local community, as well as students, employees of the involved institution and their families will be recruited, provided they do not have any condition that may limit the performance of the knee extensor muscle strength testing and/or do not have contraindications for its execution.

Description

Inclusion Criteria:

  • Individuals aged between 18-80 years of both sexes;
  • Absence of any condition (e.g., orthopedic, neuromuscular, cardiorespiratory) that may limit the assessment or directly interfere in its results.

Exclusion Criteria:

  • Failure to complete the proposed assessments for any reason;
  • A score on the Mini-Mental State Examination lower than18 for illiterate individuals and lower than 24 for literate individuals;
  • Body mass index (BMI) lower than 18 kg/m2 and higher than 40 kg/m2;
  • The manifestation of the desire to leave the study at any time for any reason.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort

Group / Cohort

A group or subgroup of participants in an observational study that is assessed for biomedical or health outcomes.
Healthy individuals aged 18 to 80 years old

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Muscle strength of knee extensors
Time Frame: 1 week
One repetition maximum test (1RM) of knee extensors
1 week

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Weight
Time Frame: 1 week
A calibrated digital scale will be used to assess the weight of the individuals in kilograms.
1 week
Height
Time Frame: 1 week
Height will be measured in meters using a vertical stadiometer. Weight and height will be combined to report BMI in kg/m^2
1 week
Lower limb measurements
Time Frame: 1 week
A measuring tape will be used to measure the length of the tíbia and the thigh circumference, measured 15 cm above the upper edge of the patela.
1 week
Comorbidities
Time Frame: 1 week
The presence of comorbidities will be assessed to characterize the sample using the Charslon Comorbidity Index. This index consists of self reported comorbidities that are categorized from 1 to 6 based on the adjusted risk of mortality. The sum of all weights results in a single score for each individual. Higher scores indicate a greater risk, and a score of zero indicates that no comorbidity was reported
1 week
Physical Activity
Time Frame: 1 week
Individuals will be asked about their physical activity, type, frequency, duration and how long they have been engaging in this activity using a simple unpublished questionnaire developed by the authors.
1 week
Cognitive Screening
Time Frame: 1 week
Cognitive screening will be conducted using the Mini-Mental State Examination (MMSE). This is a simple and easy to administer questionnaire, commmonly used in clinical and research contexts. The MMSE consists of questions grouped into seven categories to assess specific cognitive functions. The score can range from 0 to 30 points. In the Brazilian population, the suggested cutoff point for normal cognitive capacity is 18 points for illiterate individuals and 24 points for literate individuals.
1 week

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Universidade Estadual de Londrina

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Fabio O Pitta, PhD, State University of Londrina

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
July 7, 2024

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
February 2, 2026

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
April 6, 2026

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
October 15, 2024

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
October 17, 2024

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
October 18, 2024

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
October 18, 2024

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
October 17, 2024

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
October 1, 2024

More Information

Terms related to this study

Keywords

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 6.734.599

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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