Central and Peripheral Changes in Quadriceps Femoris Function After Different Types of Isometric Strength Training

November 5, 2020 updated by: Dragan Mirkov, University of Belgrade
The purpose of this investigation is to examine the effects of 6-week unilateral isometric training interventions over quadriceps femoris on maximal strength and RFD-SF parameters and cortical excitability. Isometric strength training involved either electromyostimulation, voluntary activation, or the combination of both. The second aim is to investigate the potential cross-over effect on a non-trained leg.

Study Overview

Status

Status

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

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.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

A longitudinal pre-post design with random assignment of the participants to one of three experimental groups or the control group was used. Quadriceps femoris (QF) function and cortical excitability were assessed on four occasions: prior to the intervention (pre-test), after 3 weeks of training (served for the adjustment of exercise intensity), after 6 weeks of training (post-test), and three weeks after the competition of training intervention (detraining) (Figure 1). Isometric strength training involves activation of QF applying EMS, VOLUNTARY, or the combination of both EMS and VOLUNTARY (COMBINED). The pre-test also served to familiarize participants with the training protocols and to determine the intensity of EMS needed to achieve 60%MVC. Quadriceps femoris (QF) function was assessed by MVC and RFD-SF. Cortical excitability was assessed with transcranial magnetic stimulation applied over the M1 region. Prior to the pretest, body mass and percent of body fat were assessed using a bioelectric impedance method (In Body 720; USA) and body height with a standard stadiometer. After the pretest, the participants were randomly assigned to either one of the experimental groups (EMS, VOLUNTARY, or COMBINED) and the control group (CONTROL). Experimental groups performed unilateral isometric strength training three times per week for 6 weeks. All participants were advised to refrain from all resistance training targeting the legs between pre-test and post-test.

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.
Interventional

Enrollment (Actual)

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.
52

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

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

Study Locations

  • Serbia
      • Belgrade, Serbia, 11030
        • Faculty of Sport and Physical Education, University of Belgrade

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

19 years to 30 years (Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • young healthy, physically active participants of both genders

Exclusion Criteria:

  • no history of injuries, muscle-skeletal or neurological disease, or medications intake

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

  • Primary Purpose: Basic Science
  • Allocation: Randomized
  • Interventional Model: Factorial Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Electromyostimulation - EMS
Experimental group comprised of healthy young adults that undergoes unilateral isometric training using electromyostimulation over quadriceps femoris
Other: Isometric training with electromyostimulation
Each training session (18 in total) consisted of forty 4-s contractions separated by 20 s inter-contraction intervals. The exercise intensity was close-to-identical among the sessions (60 %MVC). The force intensity was determined individually during pretest where EMS was delivered at maximal tolerable dose. Electrical stimulation was 6.25-second long and was followed by a rest period of 20-second (duty cycle 15%). Stimulation characteristics were selected among the "Compex" commercially available strength programs. The stimulation intensity was monitored on-line and determined by the subject at the start of each EMS session according to his/her pain threshold to produce a force corresponding to at least 60% of the pretest MVC score.
Experimental: Voluntary activation - VOLUNTARY
Experimental group comprised of healthy young adults that undergoes unilateral isometric training based on voluntary activation of quadriceps femoris
Other: Isometric training with voluntary activation
Each training session (18 in total) consisted of forty 4-s contractions separated by 20 s inter-contraction intervals. The exercise intensity was close-to-identical among the sessions (60 %MVC). Participants were required to reach the proscribed force level only through voluntary activation of QF. To attain the same contraction/rest ratio as in EMS, automated audible signals were delivered in accordance with the contraction-rest pattern produced by the muscle stimulation device. To ensure participants produced 60% of individual MVC during each contraction the force level was measured with a force transducer and real-time feedback was provided on a computer screen.
Experimental: Combination of EMS and VOLUNTARY - COMBINED
Experimental group comprised of healthy young adults that undergoes unilateral isometric training that combines electromyostimulation and voluntary activation of quadriceps femoris.
Other: Isometric training with combination of electromyostimulation and voluntary activation
Each training session (18 in total) consisted of forty 4-s contractions separated by 20 s inter-contraction intervals. The exercise intensity was close-to-identical among the sessions (60 %MVC). The proscribed force level was reached by the simultaneous action of EMS and VOLUNTARY. Each contraction was 6.25-second long and was followed by a rest period of 20-second (duty cycle 15%). Electrical stimulation corresponded to 30% of MVC, while the remaining 30% was achieved through voluntary muscle activation. To ensure participants produced a force corresponding to 60% of MVC during each contraction the force level was measured with a force transducer and real-time feedback was provided on a computer screen.
No Intervention: Control group - CONTROL
Group of healthy young adults who received no intervention.

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
MVC
Time Frame: Baseline
Maximal isometric force and Rate of Force Development of quadriceps femoris muscle during isometric contractions with maximal effort
Baseline
MVC
Time Frame: After 3 weeks
Maximal isometric force and Rate of Force Development of quadriceps femoris muscle during isometric contractions with maximal effort
After 3 weeks
MVC
Time Frame: After 6 weeks
Maximal isometric force and Rate of Force Development of quadriceps femoris muscle during isometric contractions with maximal effort
After 6 weeks
MVC
Time Frame: After 9 weeks
Maximal isometric force and Rate of Force Development of quadriceps femoris muscle during isometric contractions with maximal effort
After 9 weeks
The slope of the rate-of-force development scaling factor (RFD-SF)
Time Frame: Baseline
The slope of the relationship (RFD-SF) between muscle force and rate of force development during rapid isometric contractions of varying intensities
Baseline
The slope of the rate-of-force development scaling factor (RFD-SF)
Time Frame: After 3 weeks
The slope of the relationship (RFD-SF) between muscle force and rate of force development during rapid isometric contractions of varying intensities
After 3 weeks
The slope of the rate-of-force development scaling factor (RFD-SF)
Time Frame: After 6 weeks
The slope of the relationship (RFD-SF) between muscle force and rate of force development during rapid isometric contractions of varying intensities
After 6 weeks
The slope of the rate-of-force development scaling factor (RFD-SF)
Time Frame: After 9 weeks
The slope of the relationship (RFD-SF) between muscle force and rate of force development during rapid isometric contractions of varying intensities
After 9 weeks
Motor Evoked Potentials (MEP)
Time Frame: Baseline
MEPs were elicited in quadriceps femoris by transcranial magnetic stimulation (TMS) over M1 area. Motor cortex excitability was estimated by measuring the MEP amplitude (Input-Output, IO) peak to peak, caused by 20 randomized individual TMS stimulates with 100% (IO1), 120% (IO2) and 130% (IO3) of active motor threshold (AMT) intensity.
Baseline
Motor Evoked Potentials (MEP)
Time Frame: After 3 weeks
MEPs were elicited in quadriceps femoris by transcranial magnetic stimulation (TMS) over M1 area. Motor cortex excitability was estimated by measuring the MEP amplitude (Input-Output, IO) peak to peak, caused by 20 randomized individual TMS stimulates with 100% (IO1), 120% (IO2) and 130% (IO3) of active motor threshold (AMT) intensity.
After 3 weeks
Motor Evoked Potentials (MEP)
Time Frame: After 6 weeks
MEPs were elicited in quadriceps femoris by transcranial magnetic stimulation (TMS) over M1 area. Motor cortex excitability was estimated by measuring the MEP amplitude (Input-Output, IO) peak to peak, caused by 20 randomized individual TMS stimulates with 100% (IO1), 120% (IO2) and 130% (IO3) of active motor threshold (AMT) intensity.
After 6 weeks
Motor Evoked Potentials (MEP)
Time Frame: After 9 weeks
MEPs were elicited in quadriceps femoris by transcranial magnetic stimulation (TMS) over M1 area. Motor cortex excitability was estimated by measuring the MEP amplitude (Input-Output, IO) peak to peak, caused by 20 randomized individual TMS stimulates with 100% (IO1), 120% (IO2) and 130% (IO3) of active motor threshold (AMT) intensity.
After 9 weeks

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
The linearity of the rate-of-force development scaling factor (RFD-SF) relationship
Time Frame: Baseline
The linearity, described by coefficient of determination (r-squared) of the relationship (RFD-SF) between muscle force and rate of force
Baseline
The linearity of the rate-of-force development scaling factor (RFD-SF) relationship
Time Frame: After 3 weeks
The linearity, described by coefficient of determination (r-squared) of the relationship (RFD-SF) between muscle force and rate of force
After 3 weeks
The linearity of the rate-of-force development scaling factor (RFD-SF) relationship
Time Frame: After 6 weeks
The linearity, described by coefficient of determination (r-squared) of the relationship (RFD-SF) between muscle force and rate of force
After 6 weeks
The linearity of the rate-of-force development scaling factor (RFD-SF) relationship
Time Frame: After 9 weeks
The linearity, described by coefficient of determination (r-squared) of the relationship (RFD-SF) between muscle force and rate of force
After 9 weeks
M-wave
Time Frame: Baseline
The tracing of the earliest electromyography (EMG) response to the stimulation of femoral nerve
Baseline
M-wave
Time Frame: After 3 weeks
The tracing of the earliest electromyography (EMG) response to the stimulation of femoral nerve
After 3 weeks
M-wave
Time Frame: After 6 weeks
The tracing of the earliest electromyography (EMG) response to the stimulation of femoral nerve
After 6 weeks
M-wave
Time Frame: After 9 weeks
The tracing of the earliest electromyography (EMG) response to the stimulation of femoral nerve
After 9 weeks

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.
University of Belgrade

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
University of Primorska, Faculty of Health Sciences

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.
April 9, 2018

Primary Completion (Actual)

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.
June 15, 2018

Study Completion (Actual)

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.
June 15, 2018

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).
November 2, 2020

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.
November 5, 2020

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.
November 10, 2020

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.
November 10, 2020

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.
November 5, 2020

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.
November 1, 2020

More Information

Terms related to this study

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.
  • 02-672-2/09-04-2015

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

Yes

IPD Plan Description

Data will be available after a request to PI

IPD Sharing Time Frame

Six months after the completion of the study

IPD Sharing Access Criteria

No specific sharing access criteria

IPD Sharing Supporting Information Type

  • Study Protocol
  • Statistical Analysis Plan (SAP)

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

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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