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Trial registered on ANZCTR


Registration number
ACTRN12621000813886
Ethics application status
Approved
Date submitted
21/05/2021
Date registered
28/06/2021
Date last updated
28/06/2021
Date data sharing statement initially provided
28/06/2021
Type of registration
Retrospectively registered

Titles & IDs
Public title
The impact of hamstring holds or lengthening exercises on strength, muscle architecture and morphology.
Scientific title
The impact of an isometric or eccentric exercise on strength, muscle architecture and morphology in healthy, recreationally active males
Secondary ID [1] 304274 0
Nil known
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Hamstring injuries 322008 0
Sport injuries 322009 0
Condition category
Condition code
Musculoskeletal 319730 319730 0 0
Other muscular and skeletal disorders
Injuries and Accidents 320040 320040 0 0
Other injuries and accidents

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
This research will require participants to undertake a 6-week training intervention with either an isometric or eccentric hip extension exercise which are designed to improve the strength and size of your hamstring muscles. Participants will be randomly enrolled (based on their muscle ultrasound results) into a progressive intensity training program with each session lasting no more than 30min in duration. The volume and intensity of the exercise sessions will be gradually increased throughout the training period to minimise the risk of injury and to allow for progressive overload (gradual improvements in strength over time). For example, in the first training session participants will complete lower amounts of repetitions compared to their final session where they will be completing the efforts with additional weight and more repetitions.

isometric hip extension: to be used during the isometric intervention
Participants will be placed on a hip extension device and asked to contract while not moving. They will undertake this using one leg, with the opposite limb acting as a control comparison. Once they become proficient at a certain intensity, then will be added weight to ensure all efforts are undertaken at perceived intensities >8 out of 10.

eccentric hip extension: to be used during the eccentric intervention
Participants will be placed on a hip extension device and asked to contract while lowering their upper body. They will undertake this using one leg, with the opposite limb acting as a control comparison. Once they become proficient at a certain intensity, then will be added weight to ensure all efforts are undertaken at perceived intensities >8 out of 10.

Isometric exercise intervention:
Week 1 – 2 sessions, 4 repetitions, 10 seconds each repetition = 80 seconds
Week 2 – 2 sessions, 4 repetitions, 10 seconds each repetition = 80 seconds
Week 3 – 2 sessions, 4 repetitions, 10 seconds each repetition = 80 seconds
Week 4 – 2 sessions, 6 repetitions, 10 seconds each repetition = 120 seconds
Week 5 – 2 sessions, 6 repetitions, 10 seconds each repetition = 160 seconds
Week 6 – 2 sessions, 6 repetitions, 10 seconds each repetition = 200 seconds
All efforts will be performed at a perceived intensity of >8 out of 10, whilst correct exercise technique was maintained. Once intensity is <8, additional weight will be held across the chest by the participant.

Eccentric exercise intervention:
Week 1 – 2 sessions, 2 sets, 4 repetitions, 5 second per repetition = 80 seconds
Week 2 – 2 sessions, 2 sets, 4 repetitions, 5 second per repetition = 80 seconds
Week 3 – 2 sessions, 2 sets, 4 repetitions, 5 second per repetition = 80 seconds
Week 4 – 2 sessions, 3 sets, 4 repetitions, 5 second per repetition = 120 seconds
Week 5 – 2 sessions, 4 sets, 4 repetitions, 5 second per repetition = 160 seconds
Week 6 – 2 sessions, 5 sets, 4 repetitions, 5 second per repetition = 200 seconds
All efforts will be performed at a perceived intensity of >8 out of 10, whilst correct exercise technique was maintained. Once intensity is <8, additional weight will be held across the chest by the participant.

The intervention for each participant will be personalised to their perception of intensity. The researchers will ask the participant how they rate the intensity of effort following each effort. The weight held to their chest will then be modified to ensure each repetition was performed at perceived intensities >8 out of 10 with 10 as an absolutely maximum and 1 being no effort at all.

Adherence to the intervention will be monitored via a session attendance checklist (Yes/No) with the number of total attended sessions being used to compare compliance between the groups.
Intervention code [1] 320621 0
Treatment: Other
Intervention code [2] 320870 0
Prevention
Comparator / control treatment
The participants will undertake the intervention on one leg. Their contralateral leg will not receive the intervention and will act as a control comparison.
Control group
Active

Outcomes
Primary outcome [1] 327602 0
Biceps femoris long head fascicle length
Timepoint [1] 327602 0
Timepoint: baseline (one week after randomisation), mid-training (beginning week 4 of training), post training (5-7 days after last training session – 7 weeks after baseline - primary timepoint), end no-training (28 days after the post training assessment)

Instrument: two-dimensional ultrasound extended field of view images as well as small field of view images.
Secondary outcome [1] 395871 0
Unilateral, concentric average peak hamstring torque during 60deg/sec
Timepoint [1] 395871 0
Timepoint: baseline (one week after randomisation), post training (5-7 days after last training session – 7 weeks after baseline), end no-training (28 days after the post training assessment)
Instrument: isokinetic dynamometer
Secondary outcome [2] 395872 0
Unilateral, eccentric average peak hamstring torque during 60deg/sec
Timepoint [2] 395872 0
Timepoint: baseline (one week after randomisation), post training (5-7 days after last training session – 7 weeks after baseline), end no-training (28 days after the post training assessment)
Instrument: isokinetic dynamometer
Secondary outcome [3] 395873 0
Unilateral, isometric peak hamstring torque at 30deg
Timepoint [3] 395873 0
Timepoint: baseline (one week after randomisation), post training (5-7 days after last training session – 7 weeks after baseline), end no-training (28 days after the post training assessment)
Instrument: isokinetic dynamometer
Secondary outcome [4] 395874 0
Unilateral, isometric prone hip extension force
Timepoint [4] 395874 0
Timepoint: baseline (one week after randomisation), post training (5-7 days after last training session – 7 weeks after baseline), end no-training (28 days after the post training assessment)
Instrument: ForceFrame (commercially made device)
Secondary outcome [5] 395875 0
Bilateral, peak Nordic hamstring exercise force
Timepoint [5] 395875 0
Timepoint: baseline (one week after randomisation), post training (5-7 days after last training session – 7 weeks after baseline), end no-training (28 days after the post training assessment)
Instrument: Nordbord (commercially made device)
Secondary outcome [6] 395876 0
Biceps femoris long head pennation angle
Timepoint [6] 395876 0
Timepoint: baseline (one week after randomisation), mid-training (beginning week 4 of training), post training (5-7 days after last training session – 7 weeks after baseline), end no-training (28 days after the post training assessment)

Instrument: two-dimensional ultrasound extended field of view images as well as small field of view images.
Secondary outcome [7] 395877 0
Biceps femoris long head muscle thickness
Timepoint [7] 395877 0
Timepoint: baseline (one week after randomisation), mid-training (beginning week 4 of training), post training (5-7 days after last training session – 7 weeks after baseline), end no-training (28 days after the post training assessment)

Instrument: two-dimensional ultrasound extended field of view images as well as small field of view images.
Secondary outcome [8] 395878 0
Biceps femoris long head muscle volume
Timepoint [8] 395878 0
Timepoint: baseline (one week after randomisation), post training (5-7 days after last training session – 7 weeks after baseline), end no-training (28 days after the post training assessment)
Instrument: MRI scans
Secondary outcome [9] 395879 0
Biceps femoris short head muscle volume
Timepoint [9] 395879 0
Timepoint: baseline (one week after randomisation), post training (5-7 days after last training session – 7 weeks after baseline), end no-training (28 days after the post training assessment)
Instrument: MRI scans
Secondary outcome [10] 395880 0
semitendinosus muscle volume
Timepoint [10] 395880 0
Timepoint: baseline (one week after randomisation), post training (5-7 days after last training session – 7 weeks after baseline), end no-training (28 days after the post training assessment)
Instrument: MRI scans
Secondary outcome [11] 395881 0
semimembranosus muscle volume
Timepoint [11] 395881 0
Timepoint: baseline (one week after randomisation), post training (5-7 days after last training session – 7 weeks after baseline), end no-training (28 days after the post training assessment)
Instrument: MRI scans
Secondary outcome [12] 395882 0
trunk extensor muscle volume
Timepoint [12] 395882 0
Timepoint: baseline (one week after randomisation), post training (5-7 days after last training session – 7 weeks after baseline), end no-training (28 days after the post training assessment)
Instrument: MRI scans
Secondary outcome [13] 395883 0
gluteal muscle volume
Timepoint [13] 395883 0
Timepoint: baseline (one week after randomisation), post training (5-7 days after last training session – 7 weeks after baseline), end no-training (28 days after the post training assessment)
Instrument: MRI scans
Secondary outcome [14] 395884 0
Biceps femoris long head muscle anatomical cross-sectional area
Timepoint [14] 395884 0
Timepoint: baseline (one week after randomisation), post training (5-7 days after last training session – 7 weeks after baseline), end no-training (28 days after the post training assessment)
Instrument: MRI scans + ultrasound
Secondary outcome [15] 395885 0
Biceps femoris short head muscle cross-sectional area (anatomical)
Timepoint [15] 395885 0
Timepoint: baseline (one week after randomisation), post training (5-7 days after last training session – 7 weeks after baseline), end no-training (28 days after the post training assessment)
Instrument: MRI scans
Secondary outcome [16] 395886 0
semitendinosus muscle cross-sectional area (anatomical)
Timepoint [16] 395886 0
Timepoint: baseline (one week after randomisation), post training (5-7 days after last training session – 7 weeks after baseline), end no-training (28 days after the post training assessment)
Instrument: MRI scans
Secondary outcome [17] 395887 0
semimembranosus muscle cross-sectional area (anatomical)
Timepoint [17] 395887 0
Timepoint: baseline (one week after randomisation), post training (5-7 days after last training session – 7 weeks after baseline), end no-training (28 days after the post training assessment)
Instrument: MRI scans
Secondary outcome [18] 395888 0
trunk extensor muscle cross-sectional area (anatomical)
Timepoint [18] 395888 0
Timepoint: baseline (one week after randomisation), post training (5-7 days after last training session – 7 weeks after baseline), end no-training (28 days after the post training assessment)
Instrument: MRI scans
Secondary outcome [19] 395889 0
gluteal muscle cross-sectional area (anatomical)
Timepoint [19] 395889 0
Timepoint: baseline (one week after randomisation), post training (5-7 days after last training session – 7 weeks after baseline), end no-training (28 days after the post training assessment)
Instrument: MRI scans
Secondary outcome [20] 395890 0
Biceps femoris long head muscle aponeurosis geometry
Timepoint [20] 395890 0
Timepoint: baseline (one week after randomisation), post training (5-7 days after last training session – 7 weeks after baseline), end no-training (28 days after the post training assessment)
Instrument: MRI scans
Secondary outcome [21] 395891 0
Biceps femoris short head muscle aponeurosis geometry
Timepoint [21] 395891 0
Timepoint: baseline (one week after randomisation), post training (5-7 days after last training session – 7 weeks after baseline), end no-training (28 days after the post training assessment)
Instrument: MRI scans
Secondary outcome [22] 395892 0
semitendinosus muscle aponeurosis geometry
Timepoint [22] 395892 0
Timepoint: baseline (one week after randomisation), post training (5-7 days after last training session – 7 weeks after baseline), end no-training (28 days after the post training assessment)
Instrument: MRI scans
Secondary outcome [23] 395893 0
semimembranosus muscle aponeurosis geometry
Timepoint [23] 395893 0
Timepoint: baseline (one week after randomisation), post training (5-7 days after last training session – 7 weeks after baseline), end no-training (28 days after the post training assessment)
Instrument: MRI scans
Secondary outcome [24] 395894 0
trunk extensor muscle aponeurosis geometry
Timepoint [24] 395894 0
Timepoint: baseline (one week after randomisation), post training (5-7 days after last training session – 7 weeks after baseline), end no-training (28 days after the post training assessment)
Instrument: MRI scans
Secondary outcome [25] 395895 0
gluteal muscle aponeurosis geometry
Timepoint [25] 395895 0
Timepoint: baseline (one week after randomisation), post training (5-7 days after last training session – 7 weeks after baseline), end no-training (28 days after the post training assessment)
Instrument: MRI scans
Secondary outcome [26] 395896 0
hamstring bridge to fatigue test
Timepoint [26] 395896 0
Timepoint: baseline (one week after randomisation), post training (5-7 days after last training session – 7 weeks after baseline), end no-training (28 days after the post training assessment)
Instrument: 60cm box, unilateral, bridge until fatigue
Secondary outcome [27] 396977 0
Unilateral, concentric average peak hamstring torque during 180deg/sec
Timepoint [27] 396977 0
Timepoint: baseline (one week after randomisation), post training (5-7 days after last training session – 7 weeks after baseline), end no-training (28 days after the post training assessment)
Instrument: isokinetic dynamometer
Secondary outcome [28] 396978 0
Unilateral, eccentric average peak hamstring torque during 180deg/sec
Timepoint [28] 396978 0
Timepoint: baseline (one week after randomisation), post training (5-7 days after last training session – 7 weeks after baseline), end no-training (28 days after the post training assessment)
Instrument: isokinetic dynamometer
Secondary outcome [29] 396979 0
Biceps femoris long head muscle physiological cross-sectional area
Timepoint [29] 396979 0
Timepoint: baseline (one week after randomisation), post training (5-7 days after last training session – 7 weeks after baseline), end no-training (28 days after the post training assessment)
Instrument: MRI scans + ultrasound

Eligibility
Key inclusion criteria
Healthy, recreationally active males
Minimum age
18 Years
Maximum age
40 Years
Gender
Males
Can healthy volunteers participate?
Yes
Key exclusion criteria
History of significant lower limb, back or wrist injury in the last 36 months.

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 computer. Participants stratified by baseline fascicle length measures. Both the limb and group will be randomised
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?



The people analysing the results/data
Intervention assignment
Other
Other design features
Each participant will have a training limb and a control limb. This will allow within group comparisons (training vs control) and between group comparisons (training vs training; control vs control etc). Both the limb and group will be randomised
Phase
Not Applicable
Type of endpoint(s)
Efficacy
Statistical methods / analysis
Power analysis has been undertaken a-priori using G*Power. The effect size estimate used (d=1.2) in the power analysis was based on estimated differences in fascicle length between an eccentric and quasi-isometric hamstring intervention. With a power of 0.80 and an alpha of 0.05, a sample of 12 per group is required to provide sufficient power. When accounting for an approximate 10% drop out rate, twenty-eight (n=14 per group) recreationally active males will be recruited.

Where appropriate, data will be screened for normal distribution using the Shapiro–Wilk test and homoscedasticity using Levene_s test. A split-plot design ANOVA, with the within-participant variables being limb (trained or untrained) and time point (baseline, mid-training, post, end no-training) and the between-subject variable being group (eccentric or isometric), will be used to compare changes in biceps femoris long head architecture throughout the training study.

All other outcome variables will use a similar split-plot design ANOVA, however, with different time point variables (baseline, post, end no-training). Where significant limb–time–group interactions are detected, post hoc t tests will be used to identify which comparisons differed. Significance will be set at a P=0.05. Cohen’s d will also be reported for the comparison effect sizes, with the levels of effect being deemed small (d = 0.20), medium (d = 0.50), or large (d = 0.80).

Recruitment
Recruitment status
Recruiting
Date of first participant enrolment
Anticipated
Actual
Date of last participant enrolment
Anticipated
Actual
Date of last data collection
Anticipated
Actual
Sample size
Target
Accrual to date
Final
Recruitment in Australia
Recruitment state(s)
VIC
Recruitment postcode(s) [1] 34113 0
3065 - Fitzroy

Funding & Sponsors
Funding source category [1] 308651 0
University
Name [1] 308651 0
Australian Catholic University
Address [1] 308651 0
North Sydney Campus
PO Box 968
NORTH SYDNEY, NSW 2059
Country [1] 308651 0
Australia
Primary sponsor type
University
Name
Australian Catholic University
Address
Australian Catholic University
115 Victoria Parade, Fitzroy, Victoria 3065
Country
Australia
Secondary sponsor category [1] 309526 0
None
Name [1] 309526 0
Address [1] 309526 0
Country [1] 309526 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 308577 0
Australian Catholic University Human Research Ethics Committee
Ethics committee address [1] 308577 0
Australian Catholic University
North Sydney Campus
PO Box 968
NORTH SYDNEY, NSW 2059
Ethics committee country [1] 308577 0
Australia
Date submitted for ethics approval [1] 308577 0
20/04/2017
Approval date [1] 308577 0
05/07/2017
Ethics approval number [1] 308577 0
2017-97H

Summary
Brief summary
Hamstring strain injuries (HSI) represent the most common cause of time lost from competition within various running based sports. Persistent deficits in BFlh muscle volume has been found in athletes up to two years following HSI rehabilitation. Deficits in BFlh muscle volume likely impact on hamstring strength, which may contribute to persistent shortfalls in athletic performance seen after return to sport following HSI.
In pennate muscles like the BFlh, most of the force produced during contraction is transmitted through the aponeurosis to the tendon and onto the bone. Theoretically, a stronger and bigger muscle would have a larger aponeurosis than smaller muscles to safely transmit the force produced during contractions. However, this isn’t the case in the BFlh. As such, understanding the adaptability of the aponeurosis is also important for HSI prevention and rehabilitation.
Exercises that eccentrically load the hamstrings are effective at improving eccentric knee flexor strength, hamstring muscle volume and BFlh fascicle length, however the majority of interventions have focussed on knee-based exercises. There is potential that performing an eccentric only hip extension may lead to even greater adaptations, however, such an exercise has not been investigated nor has an isometric variation.
The purpose of this study is to investigate the impact of an eccentric or isometric hip-extension exercise on hamstring strength, BFlh fascicle length, muscle volume and aponeurosis size. It is hypothesized that the eccentric training group will see greater improvements in strength, fascicle length, muscle volume and aponeurosis size than the isometric group following the intervention.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 111202 0
Dr Ryan Timmins
Address 111202 0
School of Behavioural and Health Sciences, Australian Catholic University, Melbourne Campus 115 Victoria Parade, Fitzroy, Victoria 3065
Country 111202 0
Australia
Phone 111202 0
+61 3 9953 3772
Fax 111202 0
Email 111202 0
Ryan.Timmins@acu.edu.au
Contact person for public queries
Name 111203 0
Dr Ryan Timmins
Address 111203 0
School of Behavioural and Health Sciences, Australian Catholic University, Melbourne Campus 115 Victoria Parade, Fitzroy, Victoria 3065
Country 111203 0
Australia
Phone 111203 0
+61 3 9953 3772
Fax 111203 0
Email 111203 0
Ryan.Timmins@acu.edu.au
Contact person for scientific queries
Name 111204 0
Dr Ryan Timmins
Address 111204 0
School of Behavioural and Health Sciences, Australian Catholic University, Melbourne Campus 115 Victoria Parade, Fitzroy, Victoria 3065
Country 111204 0
Australia
Phone 111204 0
+61 3 9953 3772
Fax 111204 0
Email 111204 0
Ryan.Timmins@acu.edu.au

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No
No/undecided IPD sharing reason/comment
Not approved by the ethics committee.
What supporting documents are/will be available?
No other documents available
Summary results
No Results