ANZCTR - Registration

Registration number

ACTRN12621000813886

Ethics application status

Approved

Date submitted

21/05/2021

Date registered

28/06/2021

Date last updated

3/06/2022

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]

Nil known

Universal Trial Number (UTN)

Trial acronym

Linked study record

Health condition

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

Hamstring injuries

Sport injuries

Condition category

Condition code

Musculoskeletal

Other muscular and skeletal disorders

Injuries and Accidents

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]

Treatment: Other

Intervention code [2]

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]

Biceps femoris long head fascicle length

Timepoint [1]

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]

Unilateral, concentric average peak hamstring torque during 60deg/sec

Timepoint [1]

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]

Unilateral, eccentric average peak hamstring torque during 60deg/sec

Timepoint [2]

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]

Unilateral, isometric peak hamstring torque at 30deg

Timepoint [3]

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]

Unilateral, isometric prone hip extension force

Timepoint [4]

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]

Bilateral, peak Nordic hamstring exercise force

Timepoint [5]

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]

Biceps femoris long head pennation angle

Timepoint [6]

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]

Biceps femoris long head muscle thickness

Timepoint [7]

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]

Biceps femoris long head muscle volume

Timepoint [8]

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]

Biceps femoris short head muscle volume

Timepoint [9]

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]

semitendinosus muscle volume

Timepoint [10]

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]

semimembranosus muscle volume

Timepoint [11]

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]

trunk extensor muscle volume

Timepoint [12]

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]

gluteal muscle volume

Timepoint [13]

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]

Biceps femoris long head muscle anatomical cross-sectional area

Timepoint [14]

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]

Biceps femoris short head muscle cross-sectional area (anatomical)

Timepoint [15]

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]

semitendinosus muscle cross-sectional area (anatomical)

Timepoint [16]

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]

semimembranosus muscle cross-sectional area (anatomical)

Timepoint [17]

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]

trunk extensor muscle cross-sectional area (anatomical)

Timepoint [18]

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]

gluteal muscle cross-sectional area (anatomical)

Timepoint [19]

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]

Biceps femoris long head muscle aponeurosis geometry

Timepoint [20]

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]

Biceps femoris short head muscle aponeurosis geometry

Timepoint [21]

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]

semitendinosus muscle aponeurosis geometry

Timepoint [22]

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]

semimembranosus muscle aponeurosis geometry

Timepoint [23]

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]

trunk extensor muscle aponeurosis geometry

Timepoint [24]

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]

gluteal muscle aponeurosis geometry

Timepoint [25]

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]

hamstring bridge to fatigue test

Timepoint [26]

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]

Unilateral, concentric average peak hamstring torque during 180deg/sec

Timepoint [27]

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]

Unilateral, eccentric average peak hamstring torque during 180deg/sec

Timepoint [28]

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]

Biceps femoris long head muscle physiological cross-sectional area

Timepoint [29]

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

Sex

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

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

Completed

Date of first participant enrolment

Anticipated

Actual

15/02/2021

Date of last participant enrolment

Anticipated

27/09/2021

Actual

30/09/2021

Date of last data collection

Anticipated

31/12/2021

Actual

14/12/2021

Sample size

Target

24

Accrual to date

Final

24

Recruitment in Australia

Recruitment state(s)

VIC

Recruitment postcode(s) [1]

3065 - Fitzroy

Funding & Sponsors

Funding source category [1]

University

Name [1]

Australian Catholic University

Country [1]

Australia

Primary sponsor type

University

Name

Australian Catholic University

Country

Australia

Secondary sponsor category [1]

None

Name [1]

Country [1]

Ethics approval

Ethics application status

Approved

Ethics committee name [1]

Australian Catholic University Human Research Ethics Committee

Ethics committee address [1]

Australian Catholic University 
North Sydney Campus 
PO Box 968
NORTH SYDNEY, NSW 2059

Ethics committee country [1]

Australia

Date submitted for ethics approval [1]

20/04/2017

Approval date [1]

05/07/2017

Ethics approval number [1]

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

Public notes

Contacts

Principal investigator

Name

Dr Ryan Timmins

Address

School of Behavioural and Health Sciences, Australian Catholic University, Melbourne Campus 115 Victoria Parade, Fitzroy, Victoria 3065

Country

Australia

Phone

+61 3 9953 3772

Email

[email protected]

Contact person for public queries

Name

Ryan Timmins

Address

School of Behavioural and Health Sciences, Australian Catholic University, Melbourne Campus 115 Victoria Parade, Fitzroy, Victoria 3065

Country

Australia

Phone

+61 3 9953 3772

Email

[email protected]

Contact person for scientific queries

Name

Ryan Timmins

Address

School of Behavioural and Health Sciences, Australian Catholic University, Melbourne Campus 115 Victoria Parade, Fitzroy, Victoria 3065

Country

Australia

Phone

+61 3 9953 3772

Email

[email protected]

Trial Review

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