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Trial registered on ANZCTR


Registration number
ACTRN12623000532606p
Ethics application status
Submitted, not yet approved
Date submitted
11/04/2023
Date registered
19/05/2023
Date last updated
19/05/2023
Date data sharing statement initially provided
19/05/2023
Type of registration
Prospectively registered

Titles & IDs
Public title
Intrinsic foot muscle morphology and function in tennis players
Scientific title
Intrinsic foot muscle morphology and function in tennis players who have experienced foot and ankle injuries
Secondary ID [1] 309319 0
Nil
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Foot injuries 329601 0
Ankle injuries 329741 0
Condition category
Condition code
Musculoskeletal 326532 326532 0 0
Other muscular and skeletal disorders
Injuries and Accidents 326639 326639 0 0
Other injuries and accidents

Intervention/exposure
Study type
Observational
Patient registry
False
Target follow-up duration
Target follow-up type
Description of intervention(s) / exposure
The study will be conducted in the Susan Wakil Health Building Medical Imaging Suite Ultrasound Lab located on Level 3, Room 311. Only one participant will be present in the room at a time, with a single visit per participant needed. After reviewing the Participant Information Statement and consenting, the participant will complete a REDCap survey, which will consist of demographic questions such as age and years of tennis training. Validated self-report instruments, being the American Association of Orthopaedic Surgeons Foot and Ankle Questionnaire and Universal Tennis Rating Ranking Metric, will also be used to assess their injury status and tennis ability respectively. They will then have their weight, height, and full foot length measured. Static foot posture will be assessed with the Foot Posture Index to allow for comparisons of participant's feet accounting for body habitus.

After this, the student researcher will then scan both the participant's feet using a Philips iU22 ultrasound machine with a linear array 5-12MHz transducer to take measurements of the selected intrinsic foot muscles abductor hallucis and flexor digitorum brevis. The scan protocol will be followed to ensure the accuracy and reliability of measurements. The student researcher will then guide the participant to the Archercise device, for a series of gentle exercises which will be explained, performed, and measurements recorded and saved. The Archercise measurement protocol will be followed to ensure the accuracy and reliability of measurements. The student researcher will be supervised by specialists in the area of ultrasound and foot muscle structure and function. No adherence monitoring is required for this study, as the observations required will be completed at a single point in time with no follow-up visits needed. All the data collected will be stored in a password-protected University Research Data Store.

The study will take about 90 minutes to complete, as the unique time allocation is as follows:

1. Read through the participation information sheet and sign the consent form (approx.10min)
2. Complete the survey regarding demographics, tennis ability and any injury details (approx.20mins)
3. Have an ultrasound scan taken of both feet to assess the selected intrinsic foot muscles (approx. 30min)
4. Perform exercises on both feet to assess intrinsic foot muscle function on the Archercise biofeedback device (approx. 30 min)

The ultrasound protocol is unique to the study and is as follows:

The ultrasound machine will be set to a previously optimised “foot” pre-set for a consistent image setting across participants, with further optimisation of machine controls with regards to the participant's individual acoustic characteristics adjusted as necessary. The participant will be seated erect on an electric plinth, with the bed raised to a comfortable height for the operator. The knee and hip of the participant will be placed at 90 degrees flexion, with the participant's foot in a neutral position for the operator to scan. Bony landmarks will be palpated and marked with an erasable pen to ensure accurate, reproducible measurements are taken and to reduce measurement bias and operator dependence. This is to ensure the exact anatomical region is measured, as opposed to the widest or thickest aspect of the muscle.

For the abductor hallucis muscle, the medial sesamoid bone and navicular tuberosity will be marked and palpated. The probe will be placed longitudinally to the medial sesamoid bone, and the muscle will be tracked to the navicular tuberosity. Here, the operator will ensure the probe is perpendicular to the participant's foot in contact with the region and turn the probe 90 degrees, where the participant will be asked to flex their 1st digit downwards against the operator's hand, with the movement reflected on real-time imaging, to ensure the correct muscle body is measured. Images will be taken in the transverse plane, and this process will be repeated three times, with average measurements taken for increased reliability.

For the flexor digitorum brevis muscle, the probe is placed perpendicularly to the plantar aspect of the foot. The probe is then positioned to the mid-point of the true foot length, which is between the end of the 1st metatarsal and the end of the calcaneus. The participant will be asked to flex their 2nd-5th digits downwards against the operator's hand to ensure the correct muscle body is measured. Images are acquired and this process will be repeated three times, with average measurements taken for increased reliability.

The Archercise device protocol is unique to this study and is as follows:

Participants will be seated and shown the Archercise device and receive an explanation of how it functions. They will then be guided to perform four main exercises measuring:
1. Speed: Rapid raising and lowering of the arch
2. Endurance: Holding of the raised arch
3. Arch Elevation: Slowing raising the arch
4. Arch Lowering: Raising the arch and then slowing lowering it

An explanation and demonstration of each exercise will be performed before measuring, with participants able to practice before testing to ensure correct measurements are taken. Each exercise will be performed three times for 30 seconds, with average measurements taken to ensure reliability, with a 5-minute break provided in-between exercises to recover or until the participant is ready to continue to the next exercise.
Intervention code [1] 325814 0
Early Detection / Screening
Intervention code [2] 325901 0
Diagnosis / Prognosis
Comparator / control treatment
The control group will be tennis players who have not had any foot or ankle injuries. They will receive the same treatment as the injured participant group, with results from both cohorts observed and noted.
Control group
Active

Outcomes
Primary outcome [1] 334371 0
To determine the cross-sectional area of the selected intrinsic foot muscle abductor hallucis in injured and non-injured tennis players as measured by ultrasound.
Timepoint [1] 334371 0
Immediately after the ultrasound scan has been completed.
Primary outcome [2] 334428 0
To determine the cross-sectional area of the selected intrinsic foot muscle flexor digitorum brevis in injured and non-injured tennis players as measured by ultrasound.
Timepoint [2] 334428 0
Immediately after the ultrasound scan has been completed.
Primary outcome [3] 334429 0
To determine the composite functional performance of the selected intrinsic foot muscles (both abductor hallucis and flexor digitorum brevis) in injured and non-injured tennis players as measured by the relative pressure changes on the Archercise biofeedback device.
Timepoint [3] 334429 0
Immediately after the Archercise device exercises have been completed.
Secondary outcome [1] 421830 0
Nil.
Timepoint [1] 421830 0
Nil.

Eligibility
Key inclusion criteria
• Aged 18-75
• Able to read English and understand the consent process
• Willing to give written informed consent and undertake study procedures
• Have played tennis longer than 12 months and fall into a Universal Tennis Rating Ranking Metric between 1 to 16.5 (i.e. recreational to advanced level)
• Either have or have not, sustained a previous foot or ankle injury in the past 3 months to 5 years

An injury is defined as: “An event that forces a player to miss 3 or more consecutive days of tennis play, either practice or competition, or that requires medical attention from an athletic trainer, physical therapist, or doctor,” (Kovacs et al., 2014), with this injury affecting the foot or ankle region.

Kovacs, M. S., Ellenbecker, T. S., Kibler, W. B., Roetert, E. P., & Lubbers, P. (2014). Injury Trends in American Competitive Junior Tennis Players Journal of Medicine and Science in Tennis, 19, 19-23.
Minimum age
18 Years
Maximum age
75 Years
Sex
Both males and females
Can healthy volunteers participate?
Yes
Key exclusion criteria
• Having had previous foot or ankle surgery
• Pre-existing foot or ankle conditions such as rheumatoid arthritis or heel spurs
• Having trained professionally in other sports
• Have any neurological conditions affecting the foot or ankle such as stroke

Study design
Purpose
Screening
Duration
Cross-sectional
Selection
Defined population
Timing
Prospective
Statistical methods / analysis
This study will be collecting data of tennis players of both genders aged between 18-75 years old at two levels: advanced and recreational. This will encompass players who have and have not had previous foot or ankle injuries as the sample of interest and a control group respectively. This study aims to accrue a sample size of 30, as this is considered adequate for inferential statistical analysis based on the central limit theorem of distribution usually defined as n = 30 (Mascha & Vetter, 2018). Similar studies regarding tennis player foot and ankle injuries have also used this guide (e.g., Mok et al., 2021).

Foot morphology is to be assessed by using a Philips iU22 ultrasound machine with a linear array 5-12MHz transducer to take measurements of the selected intrinsic foot muscles. The ultrasound machine will be set to a previously optimised “foot” pre-set for a consistent image setting across participants, with further optimisation of machine controls adjusted with regards to the participants individual acoustic characteristics. To account for the effects of physical body size in comparing participant foot muscles, the total foot length, dorsal arch height and foot posture index will also be used to accurately account for such (McPoil et al., 2013) (Kate & Palkar, 2021). Foot function is to be assessed by the relative pressure changes as measured on the Archercise device via the electronically controlled inflatable bladder and adjustable toe and heel sensor (Latey et al., 2020). SPSS 22 will be utilised for all statistical analysis. All data will be checked for normalcy. If the data has a normal distribution, Pearson’s correlation will be used, otherwise spearmen’s correlation will be used. Intra-class correlation coefficients (ICC.2,1) are to be used to evaluate intra-rater reliability, as the results can be generalised to any single rater ideally achieving the same score to the same subject (Koo & Li, 2016). Pearson’s correlation (r) and paired t-tests (p) will be used to identify any associations between the cross-sectional areas of the muscles and their performance as measured on the Archercise device. T-tests allow the determination of how significant the differences between these groups are (Fagerland, 2012), while the Pearson’s correlation allows a calculation to be made about the strength of correlation between two variables (Ratner, 2009). The findings above will be paired with descriptive statistics, such as gender, age, BMI and playing history, to help describe sample characteristics.

Fagerland, M. W. (2012). T-tests, Non-parametric Tests, and Large Studies--a Paradox of Statistical Practice? BMC Medical Research Methodology, 12(1), 78-78. https://doi.org/10.1186/1471-2288-12-78
Kate, R., & Palkar, A. (2021). Effect of Intrinsic Foot Muscle Exercises on Foot Posture Index in Obese Individuals with Pes Planus. International Journal of Health Sciences and Research, 11(10), 280-287. https://doi.org/10.52403/ijhsr.20211037
Koo, T. K., & Li, M. Y. (2016). A Guideline of Selecting and Reporting Intraclass Correlation Coefficients for Reliability Research. Journal of Chiropractic Medicine, 15(2), 155-163. https://doi.org/10.1016/j.jcm.2016.02.012
Latey, P. J., Eisenhuth, J., McKay, M. J., Hiller, C. E., Sureshkumar, P., Nightingale, E. J., & Burns, J. (2020). Feasibility of the Archercise Biofeedback Device to Strengthen Foot Musculature. Journal of Foot and Ankle Research, 13(1), 43-43. https://doi.org/10.1186/s13047-020-00394-z
Mascha, E. J., & Vetter, T. R. (2018). Significance, Errors, Power, and Sample Size: The Blocking and Tackling of Statistics. Anesthesia and Analgesia, 126(2), 691-698. https://doi.org/10.1213/ANE.0000000000002741
McPoil, T. G., Cornwall, M. W., Abeler, M. G., Devereaux, K. J., Flood, L. J., Merriman, S. E., Sullivan, S. K., Van Der Laan, M., Villadiego, T. A., & Wilson, K. (2013). The Optimal Method to Assess the Vertical Mobility of the Midfoot: Navicular Drop versus Dorsal Arch Height Difference? Clinical Research on Foot & Ankle. https://doi.org/10.4172/2329-910x.1000104
Mok, K.-M., Ha, S. C. W., Chan, Z. Y. S., Yung, P. S. H., & Fong, D. T. P. (2021). An Inverted
Ankle Joint Orientation at Foot Strike Could Incite Ankle Inversion Sprain: Comparison Between Injury and Non-injured Cutting Motions of a Tennis Player. Foot (Edinburgh, Scotland), 48, 101853-101853. https://doi.org/10.1016/j.foot.2021.101853
Ratner, B. (2009). The Correlation Coefficient: Its Values Range Between +1 -1, or Do They?
Journal of Targeting, Measurement and Analysis for Marketing, 17(2), 139-142. https://doi.org/10.1057/jt.2009.5

Recruitment
Recruitment status
Not yet recruiting
Date of first participant enrolment
Anticipated
31/05/2023
Actual
Date of last participant enrolment
Anticipated
31/10/2023
Actual
Date of last data collection
Anticipated
31/10/2023
Actual
Sample size
Target
30
Accrual to date
Final
Recruitment in Australia
Recruitment state(s)
NSW
Recruitment postcode(s) [1] 40055 0
2021 - Moore Park
Recruitment postcode(s) [2] 40082 0
2008 - Darlington

Funding & Sponsors
Funding source category [1] 313515 0
University
Name [1] 313515 0
The University of Sydney
Country [1] 313515 0
Australia
Primary sponsor type
University
Name
The University of Sydney
Address
Room 311, Medical Imaging Suite, Level 3, Susan Wakil Health Building, D18, Western Avenue, Camperdown, NSW, Australia 2050
Country
Australia
Secondary sponsor category [1] 315291 0
None
Name [1] 315291 0
Address [1] 315291 0
Country [1] 315291 0

Ethics approval
Ethics application status
Submitted, not yet approved
Ethics committee name [1] 312702 0
The University of Sydney HREC Committee
Ethics committee address [1] 312702 0
Camperdown 2006 Sydney NSW
Ethics committee country [1] 312702 0
Australia
Date submitted for ethics approval [1] 312702 0
12/03/2023
Approval date [1] 312702 0
Ethics approval number [1] 312702 0

Summary
Brief summary
The International Tennis Federation’s 2021 Global Tennis Report tells us that a staggering 87 million people play tennis, with competitors from 142 countries competing in the 2020-2021 period (International Tennis Federation Academy, 2021). However, as the number of tennis players increases, so does the number of reported foot and ankle injuries (Kemler et al., 2022). The impact of these injuries has become of particular interest, as they are reported to be the most common severe injury in tennis players (Robison et al., 2021). Further, there is an increasing body of literature surrounding the significance of the intrinsic foot muscles (IFMs) in these injuries. Thus, a critical issue for exploration is the impact of these foot and ankle injuries on the IFMs of tennis players. By understanding this, a more detailed and accurate management plan for performance optimisation, injury prevention and therapy in both recreational and advanced tennis players can be developed (Di Giacomo et al., 2018). Therefore, the purpose of this study is to determine if there is an association between foot muscle morphology and functional performance of selected IFMs in tennis players who have, and have not, experienced previous foot or ankle injuries.

Research Questions:
The specific research questions this study aims to answer are as follows:
1. What is the relationship between foot and ankle injuries and the size of the IFMs in tennis players using ultrasound measurements?
2. What is the relationship between foot and ankle injuries and the functional performance of the selected IFMs in tennis players using measurements obtained on a novel biofeedback device?
3. What is the difference between the structural and functional performance of the IFMs in tennis players with and without foot and ankle injuries at an advanced and recreational level?

Di Giacomo, G., Ellenbecker, T. S., & Kibler, W. B. (2018). Tennis Medicine A Complete Guide to Evaluation, Treatment, and Rehabilitation (1st 2018. ed.). Springer International Publishing. https://doi.org/10.1007/978-3-319-71498-1

ITF Academy. (2021). 2021 ITF Global Tennis Report https://www.itf-
academy.com/?view=itfview&academy=103&itemid=1473

Kemler, E., Valkenberg, H., & Verhagen, E. (2022). More People More Active, But There is a Counter Site. Novice Athletes are at Highest Risk of Injury in a Large Population-based Retrospective Cross-sectional Study. BMJ Open Sport & Exercise Medicine, 8(1). https://doi.org/https://doi.org/10.1136/bmjsem-2021-001255

Robison, H. J., Boltz, A. J., Morris, S. N., Collins, C. L., & Chandran, A. (2021). Epidemiology of Injuries in National Collegiate Athletic Association Women's Tennis: 2014–2015 Through 2018–2019. Journal of Athletic Training, 56(7), 766-772. https://doi.org/10.4085/1062-6050-529-20

Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 125606 0
A/Prof Jillian Clarke
Address 125606 0
Room 311, Medical Imaging Suite, Level 3, Susan Wakil Health Building, D18, Western Avenue, Camperdown, NSW, Australia 2050
Country 125606 0
Australia
Phone 125606 0
+61 0416110260
Fax 125606 0
Email 125606 0
[email protected]
Contact person for public queries
Name 125607 0
Jillian Clarke
Address 125607 0
Room 311, Medical Imaging Suite, Level 3, Susan Wakil Health Building, D18, Western Avenue, Camperdown, NSW, Australia 2050
Country 125607 0
Australia
Phone 125607 0
+61 0416110260
Fax 125607 0
Email 125607 0
[email protected]
Contact person for scientific queries
Name 125608 0
Jillian Clarke
Address 125608 0
Room 311, Medical Imaging Suite, Level 3, Susan Wakil Health Building, D18, Western Avenue, Camperdown, NSW, Australia 2050
Country 125608 0
Australia
Phone 125608 0
+61 0416110260
Fax 125608 0
Email 125608 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?

Doc. No.TypeCitationLinkEmailOther DetailsAttachment
18793Informed consent form    385637-(Uploaded-04-04-2023-12-29-48)-Study-related document.docx
18794Study protocol    385637-(Uploaded-04-04-2023-12-30-19)-Study-related document.docx
18834Ethical approval    Will be provided once approved



Results publications and other study-related documents

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