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

NCT06603532 | Completed

• 3 other identifiers: 0120-496-2018-8P3-004320190041; 20200063
• Study Type: interventional
• Target: 36
• Locations: 1 country
• Sites: 2

Brief 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. 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.

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

Outcome Measures

Primary Outcomes (5)

• 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.

  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 (%).

  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).

  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 (%).

  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).

  Baseline and 4 weeks (post intervention)

Secondary Outcomes (2)

• knee and muscle pain

  during each training session, 3-times per week, for 4 weeks

• ratings of perceived exertion

  during each training session, 3-times per week, for 4 weeks

Study Arms (2)

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.

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.

Other: low-load resistance training

Interventions

low-load blood flow restriction (BFR) training OTHER

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 blood flow restriction (BFR) resistance training

low-load resistance training OTHER

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.

low-load resistance training

Eligibility Criteria

• Age: 18 Years - 55 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64)

You may qualify if:

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

You may not qualify if:

• 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).

Sponsors & Collaborators

• University of Ljubljana: lead
• University Medical Centre Ljubljana: collaborator
• University of Primorska: collaborator

Study Sites (2)

University of Primorska, Faculty of Health Sciences

Izola, 6310, Slovenia

Location

University of Ljubljana, Faculty of Health Sciences

Ljubljana, 1000, Slovenia

Location

MeSH Terms

Conditions

Knee Injuries

Condition Hierarchy (Ancestors)

Leg Injuries; Wounds and Injuries

Study Officials

• Alan Kacin, PhD, PT, Prof

  University of Ljubljana, Faculty of Health Studies

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: PARTICIPANT, OUTCOMES ASSESSOR
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Head of Laboratory

Model Details: prospective, single-center, double-blinded, quasi-randomized controlled clinical trial

Study Record Dates

• First Submitted: September 6, 2024
• First Posted: September 19, 2024
• Study Start: April 16, 2019
• Primary Completion: March 20, 2020
• Study Completion: September 9, 2020
• Last Updated: October 3, 2024

Record last verified: 2024-09

Data Sharing

• IPD Sharing: Will share
• Shared Documents: STUDY PROTOCOL, SAP, ICF
• Time Frame: No limit.
• 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.

Locations

SL (2)