Effect of Neuromuscular Electrical Stimulation Combined With Blood Flow Restriction on Muscular and Cardiovascular Function

Muscle Weakness Clinical Trial

Official title:

Effect of Neuromuscular Electrical Stimulation Combined With Varying Degrees of Blood Flow Restriction on Muscular and Cardiovascular Function

Clinical Trial Details — Status: Not yet recruiting

Administrative data

• NCT number: NCT03662555
• Other study ID #: Stmarys
• Status: Not yet recruiting
• Phase: N/A
• Start date: September 26, 2018
• Est. completion date: September 30, 2019

Study information

• Verified date: September 2018
• Source: St. Mary's University
• Contact: n/a
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial Summary

Neuromuscular electrical stimulation (NMES) has recently been combined with blood flow restriction (BFR) in controlled trials and has shown increased muscular strength and size compared with NMES and BFR on their own. However, none have used BFR pressures previously recommended. The first study of my Ph.D. found 40% and 80% BFR pressures to induce acute fatigue and muscle swelling. However, 80% caused higher ratings of pain and perceived exertion. The present study will determine whether NMES combined with either 40% or 80% BFR causes greater structural muscular adaptations and is perceptually easier after 6 weeks of training.

Description:

Laboratory testing will take place on 28 separate occasions, 2 familiarisation, 8 testing and 18 intervention sessions. The first session (FAM 1) will serve as a familiarisation trial to the NMES protocol, BFR stimulus and strength testing. It will be conducted 10-14 days prior to the intervention period. The second session (FAM 2) will serve as a second familiarisation trial to the NMES protocol, BFR stimulus and strength testing. This session will take place 7 days prior to the beginning of the intervention period and will serve as a standardised control period prior to the main testing. The third session (PRE) will take place 1 day prior the start of the intervention period and all future sessions will consist of strength, muscle and cardiovascular function outcome measures. The fourth session (MID) will take place the morning following 3 weeks of training. The fifth session (POST1) will take place 48 hours following 6 weeks of training. There will also be post testing sessions after three days (POST2), one week (POST3) and two weeks post intervention (POST4) to assess detraining. Participants will be provided with protein supplementation after every training session. All strength, muscle and hemodynamic measurements will be conducted at St Marys University by Paul Head. Supplements should be avoided for 72 hours prior to experimental measures and throughout the intervention period. All repeated measures will be performed at a similar time of day (± 1 h).

Recruitment information / eligibility

• Status: Not yet recruiting
• Enrollment: 50
• Est. completion date: September 30, 2019
• Est. primary completion date: July 31, 2019
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: All
• Age group: 18 Years to 45 Years

Eligibility

Inclusion Criteria:

• Healthy adults aged between 18 and 45 years old

Exclusion Criteria:

• History of lower extremity surgery, traumatic injuries to the ankle, knee, hip, pelvis and lower back

• Current musculoskeletal condition

• High blood pressure

• Cardiovascular pathology

Related Conditions & MeSH terms

• Atrophy
• Muscle Atrophy
• Muscle Weakness
• Muscular Atrophy
• Paresis

Intervention

Device:
• Neuromuscular electrical stimulation
Neuromuscular electrical simulation (NMES) Two self-adhesive electrodes (2 mm thick) will be placed over the rectus femoris, vastus medialis and vastus lateralis muscles. The electrodes will be placed on the motor points of each muscle. The stimulator discharges biphasic rectangular pulses. The stimulation frequency and duty cycle will be 50 Hz and 5 s of stimulation followed by a 5 s pause for each rep. The intensity of electrical flow will be at each subject's maximum that they can tolerate. The stimulation will be for 5 x 5 min sets with 1 min rest between sets. Blood flow restriction A handheld Doppler probe (Hi-Dop) will detect their auscultatory and visual pulse using the doppler's screen. The cuff will be inflated initially up to their systolic blood pressure and then incrementally by 10 mmHg until no auscultatory or visual pulse is detected. A percentage of 40% or 80% of each subject's LOP will then be used during the BFR conditions.

Locations

Country	Name	City	State
n/a

Sponsors (1)

Lead Sponsor	Collaborator
St. Mary's University

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Quadriceps volume and muscle architecture (3D Ultrasound)	Muscle volume of the vastus lateralis and skeletal muscle architecture will be assessed by ultrasound technique (Telemed LogicScan 128 EXT-1Z). Measurement of fascicle length and pennation angle will be acquired at mid-belly, in the mid-sagittal plane.	8 weeks
Primary	Knee extension isometric, eccentric, concentric and endurance strength (Cybex)	Maximal isometric, eccentric and concentric strength of the quadricep muscles will be measured using the same isokinetic dynamometer to assess peak force measurements (Cybex). This digital strain gauge dynamometer displays the force measurement to the nearest 0.1 N. Prior to each measurement, the instrument will be calibrated per the manufacturer's instructions and specifications. The individuals will be seated in a comfortable position with the backrest angled at 100° to the seat without shoes or orthotic device on. Maximal voluntary isometric contraction (MVIC) for the quadriceps will tested at 60 degrees from full extension using a goniometer (19-21), and the shin pad positioned 2 cm above the lateral malleolus of the fibula attached to a load cell (22).	8 weeks
Secondary	Voluntary activation	The percent of voluntary activation (%VA) will be estimated using the twitch interpolation protocol (25). Doublet stimuli were administered to the femoral nerve approximately 200-300 ms into the MVC. A second doublet will be applied approximately 3 s after the cessation of the MVC at rest (25). The stimuli were rectangular pulses of 200 ls duration and will be delivered using a high-voltage (maximal voltage = 400 V) constant-current stimulator (Digitimer DS7AH, Herthfordshire, UK).	8 weeks
Secondary	Near-infrared spectroscopy	Following 10 min of supine rest a near-infrared spectroscopy (NIRS) optode (Portamon, Artinis medical systems) was placed on the vastus lateralis and secured with an elastic bandage (Tiger Tear, Hampshire, United Kingdom) to prevent movement and covered with an optically dense black material to minimize the intrusion of extraneous light. This protocol was used to characterize the recovery of m?VO2 and has been shown to be reliable by our group and others (28-30). NIRS will be assessed PRE, MID and POST1, 2, 3 and 4.	8 weeks
Secondary	Blood pressure	A blood pressure cuff (Omron) will be placed around the subject's dominant arm and tested after 5 mins of supine rest and then immediately post each intervention session and at POST testing. To assess acute changes in systolic and diastolic blood pressure. Two readings will be taken and if they have a difference of >5 a third reading will be taken and the average recorded (27).	8 weeks