Effect of LL-BFRE Training on Volitional Muscle Activation in Subjects with Knee Joint Impairment

October 1, 2024 updated by: Alan Kacin, University of Ljubljana

Effect of Low-Load Blood Flow Restricted Training on Volitional Activation of Knee Extensor Muscles in Subjects with Knee Joint Impairment

The aim of this study was to investigate whether 4 weeks of exercise training against low mechanical resistance in combination with partial blood flow restriction has an additional therapeutic effect on the patients' ability to activate the knee extensor muscle. Patients with chronic deficits in muscle strength due to knee injuries or surgery on one leg were invited to participate in this study on a completely voluntary basis.

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

The effects of low-load exercise with blood flow restriction (BFR) on the ability to voluntarily activate skeletal muscle in people with joint injuries are poorly understood. The aim of our study was to investigate the effects of low-load BFR training on the level of voluntary activation (AL) of the quadriceps femoris muscle assessed using the interpolated twitch technique in people with different knee joint injuries. Thirty-three orthopedic patients assigned to either the BFR group or the SHAM-BFR group participated in the study. Over a period of four weeks, the participants completed 12 training sessions of unilateral knee extension and leg press at 30 RM. The BFR group trained with a pneumatic cuff-induced blood flow restriction (pressure = 120-140 mmHg), while the SHAM-BFR group trained with a sham blood flow restriction (pressure = 20 mmHg) that did not interfere with normal muscle perfusion. The assessment of knee muscle capacity and function consisted of dynamometric measurements of maximal isometric strength and endurance of the knee extensor muscles, level of voluntary muscle activation, surface electromiography, pain intensity and assessment of perceived exertion. All tests and measurements were performed twice, once before the intervention (baseline) and once at the end of the 4-week training period (POST).

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.
36

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

  • Slovenia
      • Izola, Slovenia, 6310
        • University of Primorska, Faculty of Health Sciences
      • Ljubljana, Slovenia, 1000
        • University of Ljubljana, Faculty of Health Sciences

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

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • no systemic illness,
  • no history of injuries to the contralateral knee,
  • pain intensity during exercise ≤ 2 on numeric pain rating scale (0-10).

Exclusion Criteria:

  • neuromuscular impairments,
  • spine or other lower limb injuries,
  • presence or history of any vascular diseases or deep vein thrombosis
  • pain intensity during exercise ≥ 3 on numeric pain rating scale (0-10).

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: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Double

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: low-load blood flow restriction (BFR) resistance training
Group of patients that performed the experimental exercise training against low mechanical resistance (workload) with blood flow restriction (BFR) in the active thigh muscles.
Other: low-load blood flow restriction (BFR) training
The training program lasted four weeks with three training sessions per week, for a total of 12 training sessions. Participants in the BFR group exercised with blood flow restriction caused by an inflatable cuff placed on the proximal part of the thigh and inflated to 120-140 mmHg. Subjects trained against the maximum mechanical resistance they could overcome thirty times (30 repetitions maximum; 30 RM). All training sessions were performed under the supervision of a physiotherapist and included leg press and knee extension exercises.
Sham Comparator: low-load resistance training
Group of patients that performed exercise training against low mechanical resistance (workload) with sham blood flow restriction (SHAM-BFR) in the active thigh muscles.
Other: low-load resistance training
The training program lasted four weeks with three training sessions per week, for a total of 12 training sessions. Participants in SHAM-BFR group performed an identical exercise protocol as experimental (BFR) group, while having thigh cuff inflated to only 20 mmHg, which did not affect normal muscle blood flow. Subjects trained against the maximum mechanical resistance they could overcome thirty times (30 repetitions maximum; 30 RM). All training sessions were performed under the supervision of a physiotherapist and included leg press and knee extension exercises.

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
Quadriceps muscle isometric strength
Time Frame: Baseline and 4 weeks (post intervention)
The measurement of the torque of the maximum volitional isometric contraction (MVIC) of the quadriceps femoris (QF) was performed on an isometric knee joint dynamometer. The test subject was seated, the hip joint was flexed to 85° and the lever arm was locked at 60° knee flexion. After warming up, the subject was instructed to perform the MVIC for 3-5 seconds with arms crossed over the chest, with no upper body movements allowed. Three consecutive MVICs were performed with each leg, separated by a 30-second rest period. The experimenter gave the subjects strong verbal encouragement during the tests. The highest average 1-second torque (Nm) of the three trials was considered relevant and used for further analysis.
Baseline and 4 weeks (post intervention)
Maximal voluntary activation level of quadriceps muscle
Time Frame: Baseline and 4 weeks (post intervention)
The degree of QF maximal voluntary activation (VAmax) was calculated as the ratio between the highest interpolated twitch contraction torque achieved during MVIC and the highest muscle twitch torque at rest measured during the first 10-second recovery period of after MVIC. The value is expressed as a percentage (%).
Baseline and 4 weeks (post intervention)
Quadriceps muscle isometric endurance
Time Frame: Baseline and 4 weeks (post intervention)
The test of QF isometric endurance was performed on an isometric knee joint dynamometer. The test subject was seated with the hip joint flexed to 85° and the lever arm locked at 60° knee flexion. After warming up, the test subject was instructed to attain 60% MVIC torque displayed on a computer screen and to maintain this until voluntary failure. The experimenter gave the subjects strong verbal encouragement during the test. QF muscle endurance was measured in seconds (s).
Baseline and 4 weeks (post intervention)
Voluntary activation level of quadriceps muscle during isometric endurance test
Time Frame: Baseline and 4 weeks (post intervention)
The degree of QF voluntary activation was evaluated in 10-s intervals during the isometric endurance test (VAendur). It was calculated as the ratio between the twitch torque attained in a given time interval and the highest muscle twitch torque at rest measured during the 20-second recovery period after the test. The value was expressed as a percentage (%).
Baseline and 4 weeks (post intervention)
Surface EMG amplitude of quadriceps muscle during isometric endurance test
Time Frame: Baseline and 4 weeks (post intervention)
The change in activation of v. medialis, v. lateralis and rectus f. muscles was measured using surface EMG during the isometric endurance test. The electrodes were positioned according to the SENIAM standards (Hermens et al., 2000) to avoid overlapping of the innervation zones and cross-talk between the muscles. EMG activity was amplified using a four-channel monitoring device with a sampling rate of 1000 Hz, an input impedance of 2MΏ and a bandwidth of 1-500 Hz. Smoothing the root mean square (RMS) of the filtered signal with a time window of 3000 ms was used to quantify the EMG amplitude (mV). The RMS EMG during the endurance test was expressed as percentage of the highest value attained during MVIC (% RMS EMG max).
Baseline and 4 weeks (post intervention)

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
knee and muscle pain
Time Frame: during each training session, 3-times per week, for 4 weeks
The intensity of pain at rest and at the end of each exercise repetition was rated using a numerical pain scale (NPRS) from 0-10, with 0 is the absence of pain and 10 is the worst pain imaginable.
during each training session, 3-times per week, for 4 weeks
ratings of perceived exertion
Time Frame: during each training session, 3-times per week, for 4 weeks
Ratings of perceived exertion (RPE) were assessed at the end of each exercise set using the Borg 10 category-ratio scale, with 0 is no effort and 10 is an extreme physical effort.
during each training session, 3-times per week, for 4 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 Ljubljana

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
University Medical Centre Ljubljana

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: Alan Kacin, PhD, PT, Prof, University of Ljubljana, Faculty of Health Studies

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 16, 2019

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.
March 20, 2020

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.
September 9, 2020

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).
September 6, 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.
September 16, 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.
September 19, 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 3, 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 1, 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.
September 1, 2024

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

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.
  • 0120-496-2018-8
  • P3-0043 (Other Grant/Funding Number: Slovenian Research and Innovation Agency)
  • 20190041; 20200063 (Other Grant/Funding Number: University Clinical Center Ljubljana)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

All collected IPD in anonymized form.

IPD Sharing Time Frame

No limit.

IPD Sharing Access Criteria

All IPD will be shared upon reasoned request for the purpose of further scientific analysis (i.e. systematic reviews, meta-analyzes, etc.). A proposal describing the planned analyzes must be submitted in writing to the principal investigator, Dr. Alan Kacin, by email to alan.kacin@zf.uni-lj.si.

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL
  • SAP
  • ICF

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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