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

Quadriceps Muscle Function Clinical Trial

Official title:

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

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT04624438
• Other study ID #: 02-672-2/09-04-2015
• Status: Completed
• Phase: N/A
• Start date: April 9, 2018
• Est. completion date: June 15, 2018

Study information

• Verified date: November 2020
• Source: University of Belgrade
• Contact: n/a
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial Summary

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.

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.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 52
• Est. completion date: June 15, 2018
• Est. primary completion date: June 15, 2018
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: All
• Age group: 19 Years to 30 Years

Eligibility

Inclusion Criteria:

• young healthy, physically active participants of both genders

Exclusion Criteria:

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

Related Conditions & MeSH terms

• Quadriceps Muscle Function

Intervention

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.
• 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.
• 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.

Locations

Country	Name	City	State
Serbia	Faculty of Sport and Physical Education, University of Belgrade	Belgrade

Sponsors (4)

Lead Sponsor	Collaborator
University of Belgrade	University of Belgrade, Faculty of Sport and Physical Education, University of Belgrade, Institute for Medical Research, University of Primorska, Faculty of Health Sciences

Country where clinical trial is conducted

Serbia, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	MVC	Maximal isometric force and Rate of Force Development of quadriceps femoris muscle during isometric contractions with maximal effort	Baseline
Primary	MVC	Maximal isometric force and Rate of Force Development of quadriceps femoris muscle during isometric contractions with maximal effort	After 3 weeks
Primary	MVC	Maximal isometric force and Rate of Force Development of quadriceps femoris muscle during isometric contractions with maximal effort	After 6 weeks
Primary	MVC	Maximal isometric force and Rate of Force Development of quadriceps femoris muscle during isometric contractions with maximal effort	After 9 weeks
Primary	The slope of the rate-of-force development scaling factor (RFD-SF)	The slope of the relationship (RFD-SF) between muscle force and rate of force development during rapid isometric contractions of varying intensities	Baseline
Primary	The slope of the rate-of-force development scaling factor (RFD-SF)	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
Primary	The slope of the rate-of-force development scaling factor (RFD-SF)	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
Primary	The slope of the rate-of-force development scaling factor (RFD-SF)	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
Primary	Motor Evoked Potentials (MEP)	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
Primary	Motor Evoked Potentials (MEP)	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
Primary	Motor Evoked Potentials (MEP)	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
Primary	Motor Evoked Potentials (MEP)	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	The linearity of the rate-of-force development scaling factor (RFD-SF) relationship	The linearity, described by coefficient of determination (r-squared) of the relationship (RFD-SF) between muscle force and rate of force	Baseline
Secondary	The linearity of the rate-of-force development scaling factor (RFD-SF) relationship	The linearity, described by coefficient of determination (r-squared) of the relationship (RFD-SF) between muscle force and rate of force	After 3 weeks
Secondary	The linearity of the rate-of-force development scaling factor (RFD-SF) relationship	The linearity, described by coefficient of determination (r-squared) of the relationship (RFD-SF) between muscle force and rate of force	After 6 weeks
Secondary	The linearity of the rate-of-force development scaling factor (RFD-SF) relationship	The linearity, described by coefficient of determination (r-squared) of the relationship (RFD-SF) between muscle force and rate of force	After 9 weeks
Secondary	M-wave	The tracing of the earliest electromyography (EMG) response to the stimulation of femoral nerve	Baseline
Secondary	M-wave	The tracing of the earliest electromyography (EMG) response to the stimulation of femoral nerve	After 3 weeks
Secondary	M-wave	The tracing of the earliest electromyography (EMG) response to the stimulation of femoral nerve	After 6 weeks
Secondary	M-wave	The tracing of the earliest electromyography (EMG) response to the stimulation of femoral nerve	After 9 weeks