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Trial registered on ANZCTR

Registration number

ACTRN12624000608561

Ethics application status

Approved

Date submitted

2/04/2024

Date registered

9/05/2024

Date last updated

9/05/2024

Date data sharing statement initially provided

9/05/2024

Type of registration

Prospectively registered

Titles & IDs

Public title

The effectiveness of brain stimulation and strength training on hamstring muscles

Scientific title

The effect of brain stimulation combined with strength training on hamstring muscle strength and structure in recreationally active individuals

Secondary ID [1]

None

Universal Trial Number (UTN)

Trial acronym

Linked study record

Health condition

Health condition(s) or problem(s) studied:

Hamstring muscle architecture

Condition category

Condition code

Musculoskeletal

Normal musculoskeletal and cartilage development and function

Intervention/exposure

Study type

Interventional

Description of intervention(s) / exposure

Randomised control trial to determine the effect of non invasive brain stimulation (transcranial direct current stimulation) on architectural changes resulting from a six-week eccentric training intervention (intervention total: 8 weeks, including pre-, post-testing and familiarisation) on an isokinetic dynamometer. All sessions will be supervised by a researcher.
The tDCS intervention will be 20 minutes and a 2 mA intensity, the eccentric training will include 2 - 4 sets of 4 - 6 repetitions, depending on the week. The tDCS will be applied with the anode over the contralateral motor cortex of the leg being trained and the cathode over the forehead opposite the anode prior to training. The participant comfort to tDCS will be assessed via a 0-10 RPE scale. Eccentric training will be maximal efforts performed on an isokinetic dynomometer.
Total session duration will be 2x 60mins in weeks one and two and 1x 45mins during weeks three to six. The exercise performed will be an eccentric contraction of the hamstrings.
Participants will be randomised into two groups, active-tDCS and sham-tDCS. During the first two weeks of the study, participants will attend the laboratory twice, and once in the latter four weeks. Participants will also attend pre and post training sessions to obtain baseline measures and a familiarisation session, making the full duration of the intervention eight to nine weeks.
Pre and post baseline measures taken will include, hamstring fascicle length taken via ultrasound, active motor threshold taken via transcranial magnetic stimulation and maximal muscle strength. Active motor threshold will also be taken in weeks 2, 4 and 6.
Attendance and training session will be monitored via the universities REDCap system.

Intervention code [1]

Treatment: Devices

Comparator / control treatment

Controls will be paired to the invention group via hamstring muscle fascicle length for analysis purposes. The sole difference for the control group is that they will receive sham tDCS compared to active tDCS. All other processes will be the same.
The shame condition will exactly mirror the active condition, except stimulation will only be delivered for the first 90 seconds.

Control group

Placebo

Outcomes

Primary outcome [1]

Hamstring (Biceps Femoris long head) muscle architecture

Timepoint [1]

baseline and 1 week post intervention (primary timepoint)

Primary outcome [2]

participant discomfort

Timepoint [2]

Participant discomfort will be measured every 5 minutes (total 4 measures per exposure to tDCS).

Secondary outcome [1]

Active motor threshold (AMT)

Timepoint [1]

baseline, intervention weeks 2, 4 and 6, 1 week post completion of the intervention.

Secondary outcome [2]

Maximal muscle strength

Timepoint [2]

baseline, intervention weeks 2, 4 and 6, 1 week post completion of the intervention.

Eligibility

Key inclusion criteria

1. Currently free of any major lower limb injury at the time of testing.
2. Are currently participating in regular recreational physical activity.

Minimum age

18 Years

Maximum age

40 Years

Sex

Both males and females

Can healthy volunteers participate?

Yes

Key exclusion criteria

1. Have previously suffered a seizure
2. Current or history of neurological diseases (E.g. epilepsy, Parkinson’s, Alzheimer’s, multiple sclerosis, stroke) AND have no family history of neurological disease.
3. Have embedded material in the skull such as metal fragments/plates, cochlear implants, or brain stimulation device.
4. Have sustained a concussion within the past three months.
5. Have sustained a hamstring strain injury (HSI) within the past 36 months.
6. Have never sustained an anterior cruciate ligament (ACL) injury at any point.

Study design

Purpose of the study

Prevention

Allocation to intervention

Randomised controlled trial

Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)

Allocation was not concealed

Methods used to generate the sequence in which subjects will be randomised (sequence generation)

Stratified allocation based on hamstring fascicle length. Participants will be divided into subgroups of two via hamstring fascicle length, one participant will be allocated to the active condition and the other the placebo condition

Masking / blinding

Blinded (masking used)

Who is / are masked / blinded?

The people receiving the treatment/s

Intervention assignment

Parallel

Other design features

Phase

Not Applicable

Type of endpoint/s

Statistical methods / analysis

Power calculations were performed determining that 11 participants per group are required. An ANOVA will be used to determine timepoint and group differences.

Recruitment

Recruitment status

Not yet recruiting

Date of first participant enrolment

Anticipated

3/06/2024

Actual

Date of last participant enrolment

Anticipated

31/12/2024

Actual

Date of last data collection

Anticipated

28/02/2025

Actual

Sample size

Target

Accrual to date

Final

Recruitment in Australia

Recruitment state(s)

VIC

Funding & Sponsors

Funding source category [1]

University

Name [1]

Australian Catholic University

Address [1]

Country [1]

Australia

Primary sponsor type

University

Name

Australian Catholic University

Address

Country

Australia

Secondary sponsor category [1]

None

Name [1]

Address [1]

Country [1]

Ethics approval

Ethics application status

Approved

Ethics committee name [1]

Australian Catholic University Human Research Ethics Committee

Ethics committee address [1]

ResEthics.Manager@acu.edu.au

Ethics committee country [1]

Australia

Date submitted for ethics approval [1]

06/10/2023

Approval date [1]

07/03/2024

Ethics approval number [1]

2023-3262HC

Summary

Brief summary

Hamstring strain injuries (HSIs), occurring primarily in the biceps femoris long head, have been shown to lead to an increased likelihood of re-injury. These injuries also lead to decreased muscle activity in eccentric contractions, persistent deficits in muscle architecture (i.e., the internal structure of the muscle) and motor pattern changes. Recent evidence also demonstrates that post injury, inhibition exists at the brain (or cortical) level. This inhibition can lead to reduced strength and changes in muscle architecture that can increase injury risk.

The aim of this project is to investigate the effects of a strength training program combined with active or sham tDCS on cortical inhibition, hamstring strength and biceps femoris long head architecture. Our hypothesis is that muscle fascicle length and hamstring strength will increase more in the active tDCS condition rather than the sham condition.

Trial website

Trial related presentations / publications

Public notes

Contacts

Principal investigator

Name

Mr Connor Lee Dow

Address

Australian Catholic University, 115 Victoria Parade, Fitzroy VIC 3065

Country

Australia

Phone

+61 422 401 377

Fax

[email protected]

Contact person for public queries

Name

Connor Lee Dow

Address

Australian Catholic University, 115 Victoria Parade, Fitzroy VIC 3065

Country

Australia

Phone

+61 422 401 377

Fax

[email protected]

Contact person for scientific queries

Name

Connor Lee Dow

Address

Australian Catholic University, 115 Victoria Parade, Fitzroy VIC 3065

Country

Australia

Phone

+61 422 401 377

Fax

[email protected]

Data sharing statement

Will individual participant data (IPD) for this trial be available (including data dictionaries)?

Yes

What data in particular will be shared?

De-identified data

When will data be available (start and end dates)?

Upon acceptance of the trial to an academic journal, during the 15 year holding time at ACU.

Available to whom?

Other researchers

Available for what types of analyses?

Meta-analysis.

How or where can data be obtained?

Upon request only, data can be made available via ACU Research Bank https://acuresearchbank.acu.edu.au/

What supporting documents are/will be available?

Doc. No.	Type	Email	Other Details
22044	Study protocol	[email protected]
22045	Analytic code	[email protected]	Note yet created
22046	Statistical analysis plan	[email protected]
22047	Informed consent form	[email protected]
22048	Ethical approval	[email protected]	Application ID: 2023-3262HC
22049	Data dictionary	[email protected]	De-identified data will be made available upon req... [More Details]

Results publications and other study-related documents

Documents added manually

No documents have been uploaded by study researchers.

Documents added automatically

No additional documents have been identified.

Trial Review

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Documents added automatically