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Trial registered on ANZCTR


Registration number
ACTRN12621001464853p
Ethics application status
Submitted, not yet approved
Date submitted
5/09/2021
Date registered
26/10/2021
Date last updated
25/09/2023
Date data sharing statement initially provided
26/10/2021
Type of registration
Prospectively registered

Titles & IDs
Public title
Does strength training influence hamstring muscle-tendon adaptations and changes in running biomechanics?
Scientific title
Does chronic strength training influence hamstring muscle-tendon adaptations and changes in running biomechanics in healthy, recreationally active males?
Secondary ID [1] 305118 0
None
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Hamstring strain injuries 323342 0
Condition category
Condition code
Physical Medicine / Rehabilitation 320913 320913 0 0
Physiotherapy
Musculoskeletal 320914 320914 0 0
Other muscular and skeletal disorders

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
Healthy, male participants will perform 10 weeks (following randomisation) of either maximal eccentric- or concentric-only knee flexion strength training on an isokinetic dynamometer, consisting of two sessions per week for the duration of the intervention period. This will be conducted at the Movement Analysis Research Laboratory (403.B1.02A) and Exercise Science Research Lab (420.4.12) at Australian Catholic University, Melbourne. Duration of each training session will be approximately 30 mins and all sessions will be completed one-on-one with the investigator.

Across the training period, the volume (number) of contractions will be increased as per the progression outlined below:

Week 1:
Frequency (days per week) = 2
Sets = 3
Repetitions = 6
Total repetitions = 36

Week 2:
Frequency (days per week) = 2
Sets = 3
Repetitions = 6
Total repetitions = 36

Week 3:
Frequency (days per week) = 2
Sets = 4
Repetitions = 6
Total repetitions = 48

Week 4:
Frequency (days per week) = 2
Sets = 4
Repetitions = 6
Total repetitions = 48

Week 5:
Frequency (days per week) = 2
Sets = 5
Repetitions = 6
Total repetitions = 60

Week 6:
Frequency (days per week) = 2
Sets = 5
Repetitions = 6
Total repetitions = 60

Week 7:
Frequency (days per week) = 2
Sets = 6
Repetitions = 6
Total repetitions = 72

Week 8:
Frequency (days per week) = 2
Sets = 6
Repetitions = 6
Total repetitions = 72

Week 9:
Frequency (days per week) = 2
Sets = 6
Repetitions = 8
Total repetitions = 96

Week 10:
Frequency (days per week) = 2
Sets = 6
Repetitions = 8
Total repetitions = 96

All contractions will be completed at 60deg/sec on the isokinetic dynamometer. All participants will perform two sets of three warm-up efforts at 60deg/sec, in the contraction mode used for their training. For all training repetitions, the concentric training participants will be moved to full knee extension (0deg) by the investigator and will be instructed to maximally flex their knee through to 90deg of knee flexion. The lever arm will then be returned to full knee extension, and the subsequent repetition completed. This will be undertaken until all repetitions are completed in their respective set, with a 30 second rest period between sets.

The eccentric training participants will begin with their knee at 90deg of flexion. They will then be instructed to maximally flex against the lever arm until full knee extension is reached (0deg). The the lever arm will then be re-positioned to 90deg of knee flexion for the subsequent contraction. This will be undertaken until all repetitions are completed in each set, with a 30 second rest period between sets. Each training session will be separated by at least 48 hours. Participants will also be asked to refrain from additional hamstring strength training during this intervention period.

The participants will be paired according to biceps femoris long head aponeurosis width and randomly assigned to (allocation ratio, 1:1) either concentric- or eccentric-only knee flexor strength training group in a randomly selected limb (the contralateral limb served as a within-participant control).
Intervention code [1] 321516 0
Treatment: Other
Comparator / control treatment
Only one limb will receive the strength training stimulus, with the contralateral limb acting as a within-participant control limb receiving no intervention, per previous investigations from our laboratory (Timmins et al, 2016). We would also compare the training limbs between groups.
Control group
Active

Outcomes
Primary outcome [1] 328698 0
Biceps femoris long head proximal aponeurosis anatomical dimensions.

Assessed via MRI imaging and segmentation software
Timepoint [1] 328698 0
Pre-intervention, 5 weeks post-intervention commencement, 10 weeks post-intervention commencement (primary endpoint)
Primary outcome [2] 329098 0
Biceps femoris long head distal aponeurosis anatomical dimensions.

Assessed via MRI imaging and segmentation software
Timepoint [2] 329098 0
Pre-intervention, 5 weeks post-intervention commencement, 10 weeks post-intervention commencement (primary endpoint)
Primary outcome [3] 329099 0
Composite measure of biceps femoris long head muscle cross sectional area and muscle volume.

Assessed via MRI imaging and segmentation software
Timepoint [3] 329099 0
Pre-intervention, 5 weeks post-intervention commencement, 10 weeks post-intervention commencement (primary endpoint)
Secondary outcome [1] 400019 0
Lower body joint kinematics and kinetics during sprinting assessed via motion capture analysis, ground reaction force, and electromyography (EMG) data which will all be collected simultaneously.

Timepoint [1] 400019 0
Pre-intervention, and 10 weeks post-intervention commencement
Secondary outcome [2] 400022 0
Composite measure of diffusion parameters (eg mean diffusivity, radial diffusivity and fractional anistropy) of all hamstring muscles via MRI diffusion tensor imaging/tractography procedures.
Timepoint [2] 400022 0
Pre-intervention, 5 weeks post-intervention commencement, 10 weeks post-intervention commencement
Secondary outcome [3] 400394 0
Knee flexor muscle torque

Assessed via isokinetic dynamometry.
Timepoint [3] 400394 0
Pre-intervention, 5 weeks post-intervention commencement, 10 weeks post-intervention commencement
Secondary outcome [4] 400395 0
Biceps femoris long head muscle architecture.

Assessed via 2d ultrasound.
Timepoint [4] 400395 0
Pre-intervention, 5 weeks post-intervention commencement, 10 weeks post-intervention commencement.
Secondary outcome [5] 401493 0
Biceps femoris long head muscle architecture

Assessed via MRI diffusion tensor imaging/tractography procedures
Timepoint [5] 401493 0
Pre-intervention, 5 weeks post-intervention commencement, 10 weeks post-intervention commencement.

Eligibility
Key inclusion criteria
Healthy, recreationally active males.

This requires participants to have no current lower limb injury.

To be deemed recreationally active participants are required to be completing a minimum of two sessions per week of physical activity
Minimum age
18 Years
Maximum age
40 Years
Sex
Males
Can healthy volunteers participate?
Yes
Key exclusion criteria
Hamstring strain injury within the previous 36 months

History of anterior cruciate ligament injury

Any other significant lower limb musculoskeletal injury in the previous 12 months

Any participants assessed as a moderate risk of an adverse event due to exercise (as measured on the ESSA pre-exercise screening tool)

Any participants with a pacemaker, or with a non-MRI-compatible medical device will be excluded from participation.

Study design
Purpose of the study
Treatment
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Allocation is not concealed
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Simple randomisation using a randomisation table created by RedCap software (i.e. computerised sequence generation)

Average of proximal biceps femoris long head aponeurosis width will be used for the stratification following the baseline MRI scan.

The participants will be paired according to biceps femoris long head aponeurosis width and randomly assigned to (allocation ratio, 1:1) either the concentric- or eccentric-only knee flexor strength training group. The limb that receives the strength training intervention will be randomised whilst the contralateral limb will serve as a within-participant control.
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?



Intervention assignment
Parallel
Other design features
Phase
Not Applicable
Type of endpoint/s
Efficacy
Statistical methods / analysis
Sample size analysis was completed a priori using G-Power. The analysis was based on the anticipated differences in muscle-aponeurosis adaptations after the strength training intervention. To date there has been no studies to demonstrate this within the biceps femoris long head aponeurosis. Massey and colleagues (2020) reported a small effect when assessing the impact of an isometric training intervention on vastus lateralis aponeurosis area (Cohen’s d = 0.32). Another study found a large effect when assessing the impact of an eccentric- or concentric- only intervention on the architectural characteristics of the biceps femoris long head (d range = 2.65-2.98) (Timmins et al, 2016). Additionally, other work has previously found large effect sizes of biceps femoris long head muscle volume changes (d range =1.03-2.24) following hip extension and Nordic hamstring exercise training (Bourne et al, 2017). Therefore, an effect size of 1.2 was deemed reasonable. Power was set at 80% with an alpha level of 0.05 returning a calculated sample size of 12 per group. We will aim to recruit 28 participants to account for a 10% attrition rate.

Musculoskeletal modelling simulations for sprinting will be created from muscle activation and musculotendon length change and defined based on the measured joint kinematics and inverse dynamic simulations of sprinting (Delp et al, 2007). Local fibre stress and strain will also be assessed via a finite element modelling approach and defined based upon muscle activation and musculotendon length changes (Blemker et al, 2005)

A linear mixed model approach will be used to assess the changes in the biceps femoris long head muscle-aponeurotic dimensions. This approach will also be used to assess changes in biceps femoris long head muscle architecture, diffusion parameters, knee flexor torque, 3D biomechanics variables (lower limb joint kinematics and kinetics), and musculotendinous demands (assessed via modelling techniques) during high-speed running. Comparisons will be made within groups (control limb vs training limb) as well as between groups (training limb between groups). Significance will be set an alpha level p<0.05, Cohen’s effect size (d) will be calculated to provide clinical meaningfulness of the differences (Lakens, 2013).

Recruitment
Recruitment status
Not yet recruiting
Date of first participant enrolment
Anticipated
31/03/2024
Actual
Date of last participant enrolment
Anticipated
31/12/2024
Actual
Date of last data collection
Anticipated
28/02/2025
Actual
Sample size
Target
28
Accrual to date
Final
Recruitment in Australia
Recruitment state(s)
VIC

Funding & Sponsors
Funding source category [1] 309506 0
University
Name [1] 309506 0
Australian Catholic University/ SPRINT Research Centre
Country [1] 309506 0
Australia
Funding source category [2] 309509 0
Charities/Societies/Foundations
Name [2] 309509 0
Physiotherapy Research Foundation
Country [2] 309509 0
Australia
Primary sponsor type
University
Name
Australian Catholic University
Address
Address
Exercise Science Offices
The Daniel Mannix Building
Level 1, 17 Young St
Fitzroy, VIC, 3065

Postal address
Locked Bag 4115
Fitzroy, MDC, VIC, 3065
Country
Australia
Secondary sponsor category [1] 310491 0
None
Name [1] 310491 0
Address [1] 310491 0
Country [1] 310491 0

Ethics approval
Ethics application status
Submitted, not yet approved
Ethics committee name [1] 309292 0
Australian Catholic University Human Research Ethics Committee (HREC)
Ethics committee address [1] 309292 0
North Sydney Campus (MacKillop)
Tenison Woods House
8-20 Napier Street-Level 16 (532.16)
North Sydney NSW 2060

Postal
PO Box 968
North Sydney
NSW 2059
Ethics committee country [1] 309292 0
Australia
Date submitted for ethics approval [1] 309292 0
23/08/2021
Approval date [1] 309292 0
Ethics approval number [1] 309292 0

Summary
Brief summary
This project will investigate how biceps femoris long head muscle and aponeurosis morphology are influenced after undertaking either a chronic concentric- or eccentric-only resistance training intervention in healthy, recreationally active males. A secondary aim is to determine the impact of these contraction mode specific interventions on biceps femoris long head muscle architecture, diffusion parameters, knee flexor strength, three-dimensional (3D) biomechanics and the musculotendinous demands experienced during running. We hypothesise this muscle-aponeurotic adaptation will be the major driving factor that influences the intrinsic tissue demands during gait (such as musculotendinous strain or fibre strain) instead of due to changes in joint kinematics or kinetics.
Trial website
Trial related presentations / publications
Public notes
There are no known harmful side-effects associated with temporary exposure to the magnetic field and radiofrequencies used by MRI scanners. Many forms of medical or bio-stimulation implants (e.g., cardiac pacemakers) are contraindicated for this form of scanning. To ensure it is safe for the participant to undergo MR imaging they will be thoroughly screened by investigators and an MRI technician prior to entering the MRI facility. Some people also report feeling claustrophobic during MRI scanning, however, to minimise this risk they will be provided with a panic button which enables them to stop the scan at any time if they feel uncomfortable.

As this study requires the participant to run on a motorised treadmill there is a risk of musculoskeletal injury (e.g., muscle strain injury from high-speed running, bone fracture due to a fall from the treadmill) and/or cardiovascular events (e.g., myocardial infarction). To minimise this risk, the participant will be screened for any conditions that could increase your risk of injury by completing the Exercise and Sports Science Australia (ESSA) Adult Pre-Exercise Screening tool to help identify any existing health conditions that may exclude the participant from the study. Additionally, the participant will be familiarised with the testing protocol and equipment and complete a warmup before the running trials. For running on the motorised treadmill the participant will also be fitted with a safety harness.

Contacts
Principal investigator
Name 113654 0
Mr Scott Hulm
Address 113654 0
Exercise Science Offices
The Daniel Mannix Building
Level 1, 17 Young St
Fitzroy, VIC, 3065

Postal address
Locked Bag 4115
Fitzroy, MDC, VIC, 3165
Country 113654 0
Australia
Phone 113654 0
+613 9953 3030
Fax 113654 0
Email 113654 0
[email protected]
Contact person for public queries
Name 113655 0
Mr Scott Hulm
Address 113655 0
Exercise Science Offices
The Daniel Mannix Building
Level 1, 17 Young St
Fitzroy, VIC, 3065

Postal address
Locked Bag 4115
Fitzroy, MDC, VIC, 3165
Country 113655 0
Australia
Phone 113655 0
+613 9953 3030
Fax 113655 0
Email 113655 0
[email protected]
Contact person for scientific queries
Name 113656 0
Mr Scott Hulm
Address 113656 0
Exercise Science Offices
The Daniel Mannix Building
Level 1, 17 Young St
Fitzroy, VIC, 3065

Postal address
Locked Bag 4115
Fitzroy, MDC, VIC, 3165
Country 113656 0
Australia
Phone 113656 0
+613 9953 3030
Fax 113656 0
Email 113656 0
[email protected]

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No
No/undecided IPD sharing reason/comment


What supporting documents are/will be available?

No Supporting Document Provided



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.