Arthrogenic Muscle InhibitionNCT06603532
Effect of LL-BFRE Training on Volitional Muscle Activation in Subjects with Knee Joint Impairment
A study testing low-load blood flow restriction (BFR) training and low-load resistance training in people with Arthrogenic Muscle Inhibition and Knee Injuries, run by University of Ljubljana at 2 sites in Slovenia.
Trial summary
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. Read more about this study
- Who is it for?
- Ages 18 to 55 years
- Conditions the study is for
- Arthrogenic Muscle Inhibition, Knee Injuries, Knee Surgery
- What is being tested?
- low-load blood flow restriction (BFR) training and low-load resistance training
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 36 participants
- Where
- 2 sitesSlovenia
- Study dates
- 16 Apr 2019to 9 Sep 2020
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 55 years
- All sexes
- No healthy volunteers
- Adult
Who may be able to join
- no systemic illness,
- no history of injuries to the contralateral knee,
- pain intensity during exercise ≤ 2 on numeric pain rating scale (0-10).
Who cannot join
- 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).
Trial locations and contacts
2 sites in 1 country.
Slovenia2 sites
University of Primorska, Faculty of Health Sciences
Izola, 6310
University of Ljubljana, Faculty of Health Sciences
Ljubljana, 1000
About this study
Official title: 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.
Read the 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).
- Conditions
- Arthrogenic Muscle Inhibition, Knee Injuries, Knee Surgery
- Being tested
- low-load blood flow restriction (BFR) training, low-load resistance training
- Keywords
- arthrogenic muscle inhibition, knee injury, level of volunaty muscle activation, blood flow restriction resistance exercise, controlled clinical trial
- Medical subject headings
- Knee Injuries
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
low-load blood flow restriction (BFR) trainingOther
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.
low-load resistance trainingOther
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.
| Study group | Role | What they receive |
|---|---|---|
| low-load blood flow restriction (BFR) resistance training | Experimental | Group of patients that performed the experimental exercise training against low mechanical resistance (workload) with blood flow restriction (BFR) in the active thigh muscles. Receives: Other: low-load blood flow restriction (BFR) training |
| low-load resistance training | Sham comparator | Group of patients that performed exercise training against low mechanical resistance (workload) with sham blood flow restriction (SHAM-BFR) in the active thigh muscles. Receives: Other: low-load resistance training |
What is being measured
The primary outcome is the main question the study is designed to answer.
Quadriceps muscle isometric strength
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.
Measured: Baseline and 4 weeks (post intervention)
Maximal voluntary activation level of quadriceps muscle
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 (%).
Measured: Baseline and 4 weeks (post intervention)
Quadriceps muscle isometric endurance
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).
Measured: Baseline and 4 weeks (post intervention)
Voluntary activation level of quadriceps muscle during isometric endurance test
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 (%).
Measured: Baseline and 4 weeks (post intervention)
Surface EMG amplitude of quadriceps muscle during isometric endurance test
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).
Measured: Baseline and 4 weeks (post intervention)
Secondary outcomes (2)
knee and muscle pain
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.
Measured: during each training session, 3-times per week, for 4 weeks
ratings of perceived exertion
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.
Measured: during each training session, 3-times per week, for 4 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted19 Sep 2024
- Study start16 Apr 2019
- Primary completion20 Mar 2020
- Study completion9 Sep 2020
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Arthrogenic Muscle InhibitionStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- prospective, single-center, double-blinded, quasi-randomized controlled clinical trial
- Masking
- Double blind
- Who is masked
- Participant, Outcomes assessor
- Enrolment
- 36 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of Ljubljana
- Sponsor type
- University, hospital or other
- Collaborators
- University Medical Centre Ljubljana, University of Primorska
- Responsible party
- Principal investigator, Alan Kacin, University of Ljubljana
- Investigators
- Alan Kacin, PhD, PT, Prof, Principal investigator, University of Ljubljana, Faculty of Health Studies
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06603532
- Sponsor's protocol ID
- 0120-496-2018-8
- Other IDs
- P3-0043, 20190041; 20200063
- Status last verified
- Sep 2024
- First submitted
- 6 Sep 2024
- Last updated
- 3 Oct 2024
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: All collected IPD in anonymized form.
Study at a glance
From the registry record, last updated by the sponsor on 3 Oct 2024. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Effect of Low-Load Blood Flow Restricted Training on Volitional Activation of Knee Extensor Muscles in Subjects with Knee Joint Impairment
- ClinicalTrials.gov ID
- NCT06603532
- Acronym / sponsor ID
- 0120-496-2018-8
- Conditions
- Arthrogenic Muscle Inhibition, Knee Injuries, Knee Surgery
- Keywords
- arthrogenic muscle inhibition, knee injury, level of volunaty muscle activation, blood flow restriction resistance exercise, controlled clinical trial
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 36 participants (actual)
- Lead sponsor
- University of LjubljanaUniversity, hospital or other
- Collaborators
- University Medical Centre Ljubljana, University of Primorska
- Study start
- 16 Apr 2019 (actual)
- Primary completion
- 20 Mar 2020 (actual)
- Study completion
- 9 Sep 2020 (actual)
- First posted
- 19 Sep 2024 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
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 design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind (participant, outcomes assessor)
- Number of arms
- 2
- Model description
- prospective, single-center, double-blinded, quasi-randomized controlled clinical trial
| Arm | Type | Receives |
|---|---|---|
| low-load blood flow restriction (BFR) resistance training | Experimental | Other: low-load blood flow restriction (BFR) trainingGroup of patients that performed the experimental exercise training against low mechanical resistance (workload) with blood flow restriction (BFR) in the active thigh muscles. |
| low-load resistance training | Sham comparator | Other: low-load resistance trainingGroup of patients that performed exercise training against low mechanical resistance (workload) with sham blood flow restriction (SHAM-BFR) in the active thigh muscles. |
Who may qualify
- Ages
- 18 to 55 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult
Key inclusion criteria (3 listed)
- no systemic illness,
- no history of injuries to the contralateral knee,
- pain intensity during exercise ≤ 2 on numeric pain rating scale (0-10).
Key exclusion criteria (4 listed)
- 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).
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| low-load blood flow restriction (BFR) trainingThe 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. | Other | low-load blood flow restriction (BFR) resistance training |
| low-load resistance trainingThe 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. | Other | low-load resistance training |
Primary outcome
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.
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 (%).
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).
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 (%).
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).
2 secondary outcomes
knee and muscle pain
Time frame: 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
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 3 Oct 2024.
- Individual participant dataSharing planned: Yes. All collected IPD in anonymized form.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Alan Kacin, PhD, PT, Prof principal investigator
University of Ljubljana, Faculty of Health Studies
2 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing low-load blood flow restriction (BFR) training and low-load resistance training in people with Arthrogenic Muscle Inhibition and Knee Injuries, run by University of Ljubljana at 2 sites in Slovenia.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 4 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 3 Oct 2024. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 2 sites in Slovenia. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Quadriceps muscle isometric strength (time frame: Baseline and 4 weeks (post intervention)). The study lists 5 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 3 Oct 2024.