Protocol summary

Study aim
To investigate the acute, chronic, and detraining effects of dynamic stretching and tissue flossing on muscle function, sprint performance, balance, and proprioception in soccer players with hamstring shortness
Design
a three-arm parallel randomized controlled trial with a computer-generated random sequence
Settings and conduct
This study will be conducted in sports sciences in Qazvin, with participants randomly assigned to one of three groups: dynamic stretching, tissue flossing, or control. Assessments will occur in four phases: pre-test, immediately after the first session, after six weeks of training, and after three weeks of detraining.
Participants/Inclusion and exclusion criteria
Inclusion Criteria: (1) Male amateur soccer players (who play in local leagues without a financial contract) aged 14 to 17 years; (2) Minimum of 3 years of continuous soccer participation within organized soccer clubs; (3) Clinically diagnosed with hamstring shortness, defined as a score of more than 33 degrees on the active knee extension test; (4) No prohibition on using dynamic stretching or tissue flossing, with the approval of a medical professional. Exclusion Criteria: (1) Lower limb injuries during the study; (2) Inability to commit to the full study duration and prescribed protocols, including more than two consecutive or three total absences.
Intervention groups
Three groups will participate: the flossing group, which uses a floss band with active movements; the dynamic stretching group; and the control group. All sessions will begin with a standardized warm-up.
Main outcome variables
Knee extension range of motion Hip flexion range of motion Hamstring and quadriceps strength Muscle power Sprint performance Dynamic balance Knee joint repositioning error

General information

Reason for update
Acronym
IRCT registration information
IRCT registration number: IRCT20251202068197N1
Registration date: 2025-12-05, 1404/09/14
Registration timing: prospective

Last update: 2025-12-05, 1404/09/14
Update count: 0
Registration date
2025-12-05, 1404/09/14
Registrant information
Name
Mohammad Alghosi
Name of organization / entity
The University of Guilan
Country
Iran (Islamic Republic of)
Phone
+98 13 3369 0274
Email address
mohammadalghosi@phd.guilan.ac.ir
Recruitment status
Recruitment complete
Funding source
Expected recruitment start date
2025-12-10, 1404/09/19
Expected recruitment end date
2025-12-30, 1404/10/09
Actual recruitment start date
empty
Actual recruitment end date
empty
Trial completion date
empty
Scientific title
Acute, chronic, and detraining effects of dynamic stretching and tissue flossing on muscle function, sprint performance, balance, and proprioception, in soccer players with hamstring shortness: a three-arm parallel randomized controlled trial protocol
Public title
Effects of dynamic stretching and tissue flossing on muscle function, sprint performance, balance, and proprioception in soccer players with hamstring shortness
Purpose
Supportive
Inclusion/Exclusion criteria
Inclusion criteria:
Male amateur soccer players (who play in local leagues without a financial contract) aged 14 to 17 years Minimum of 3 years of continuous soccer participation within organized soccer clubs Clinically diagnosed with hamstring shortness, defined as a score of more than 33 degrees on the active knee extension test No prohibition on using dynamic stretching or tissue flossing, with the approval of a medical professional
Exclusion criteria:
Lower limb injuries during the study Inability to commit to the full study duration and prescribed protocols, including more than two consecutive or three total absences
Age
From 14 years old to 17 years old
Gender
Male
Phase
N/A
Groups that have been masked
No information
Sample size
Target sample size: 57
Randomization (investigator's opinion)
Randomized
Randomization description
Eligible participants will be randomly assigned to one of three groups, including a dynamic stretching group, a tissue flossing group, or a control group, using a computer-generated randomization sequence from https://www.randomizer.org. The randomization list is securely stored on a password-protected computer, accessible only to the researcher responsible for participant allocation. Recruitment staff and others will not have access to this information.
Blinding (investigator's opinion)
Not blinded
Blinding description
Placebo
Not used
Assignment
Parallel
Other design features

Secondary Ids

empty

Ethics committees

1

Ethics committee
Name of ethics committee
Research Ethics Committees of University of Guilan
Street address
5th Kilometer of Persian Gulf Highway, Rasht, Guilan Province, Iran
City
Rasht
Province
Guilan
Postal code
۴۱۹۹۶۱۳۷۷۶
Approval date
2025-12-01, 1404/09/10
Ethics committee reference number
IR.GUILAN.REC.1404.149

Health conditions studied

1

Description of health condition studied
Limited knee range of motion
ICD-10 code
M25.6
ICD-10 code description
Stiffness of joint, not elsewhere classified

Primary outcomes

1

Description
In the current study, hamstring shortness, knee range of motion, hamstring flexibility, muscle strength, muscle power, sprint performance, dynamic balance, and joint position sense are being investigated.
Timepoint
Baseline, Acute effect measurement (after the first session), Chronic effect measurement (after 6 weeks of training), and Follow-up measurement (after 3 weeks of detraining)
Method of measurement
The following outcome measures will be assessed using the corresponding tests: hamstring shortness and knee range of motion via the active knee extension test; hamstring flexibility via the active straight leg raise test; muscle strength (isometric and eccentric hamstring, isometric quadriceps) using a handheld dynamometer; lower-body muscle power via the countermovement jump test; sprint performance using the MySprint app protocol; dynamic balance via the Y-Balance test; and knee joint proprioception via a joint position sense test.

Secondary outcomes

empty

Intervention groups

1

Description
Intervention group: Participants assigned to the tissue flossing group will undergo floss band application, which will be anchored just above the distal third of the thigh between the anterior superior iliac spine and the patella. The band will be applied in a spiral pattern from distal to proximal, maintaining 50% tension and 50% overlap between layers, and will remain continuously applied throughout each session without removal between sets. The Tissue Flossing Group will follow a 6-week progressive protocol. Weeks 1–2 involved 2 sets of 15 repetitions of two exercises (Active leg swings and Active standing toe touches), which will be performed three times per week. Weeks 3–4 progressed to 3 sets of 20 repetitions of Active leg swings and Dynamic standing hamstring stretches, also three times weekly. Weeks 5–6 involved 4 sets of 20 repetitions of Active leg swings and standing hamstring scoop exercises, which will be performed four times per week.
Category
Rehabilitation

2

Description
Intervention group: The Dynamic Stretching Group will complete a separate 6-week progressive protocol. Weeks 1–2 will involve 3 sets of 15 repetitions of Active leg swings and Lunges with eccentric hamstring windmills, to be performed three times per week at a controlled end-range. Weeks 3–4 will increase to 4 sets of 20 repetitions with a slightly increased range of motion. Weeks 5–6 will involve 5 sets of 20 repetitions, with further increased range and speed, to be performed four times per week. For both groups, exercises will be performed at a moderate tempo, 3 seconds per repetition (2-second eccentric, 1-second concentric), synchronized to a metronome at 60 BPM, with a 20-second rest interval between sets. All protocols will be conducted in the morning (10–12 AM) during the pre-competition active phase, with exercises performed bilaterally.
Category
Rehabilitation

3

Description
Control group: The control group received no other intervention, except for the same warm-up as the other groups.
Category
Other

Recruitment centers

1

Recruitment center
Name of recruitment center
Faculty of Physical Education and Sports Sciences, University of Guilan Complex, Persian Gulf Highwa
Full name of responsible person
Mohammad Alghosi
Street address
Faculty of Physical Education and SportsPersian Gulf Highway (Km. 5 of Rasht-Qazvin Road), Rasht, Iran.
City
Rasht
Province
Guilan
Postal code
۴۱۹۹۶۱۳۷۷۶
Phone
+98 933 611 7047
Email
mohammadalghosi9@gmail.com

Sponsors / Funding sources

1

Sponsor
Name of organization / entity
University of Guilan
Full name of responsible person
Hassan Daneshmandi
Street address
Faculty of Physical Education and Sports Sciences, University of Guilan Complex, Persian Gulf Highway (Km. 5 of Rasht-Qazvin Road), Rasht, Iran.
City
Rasht
Province
Guilan
Postal code
۴۱۹۹۶۱۳۷۷۶
Phone
+98 933 611 7047
Email
mohammadalghosi9@gmail.com
Grant name
Grant code / Reference number
Is the source of funding the same sponsor organization/entity?
No
Title of funding source
University of Guilan
Proportion provided by this source
1
Public or private sector
Private
Domestic or foreign origin
Domestic
Category of foreign source of funding
empty
Country of origin
Type of organization providing the funding
Persons

Person responsible for general inquiries

Contact
Name of organization / entity
University of Guilan
Full name of responsible person
Hassan Daneshmandi
Position
Professor
Latest degree
Ph.D.
Other areas of specialty/work
Sport Science
Street address
Faculty of Physical Education and Sports Sciences, University of Guilan Complex, Persian Gulf Highway (Km. 5 of Rasht-Qazvin Road), Rasht, Iran.
City
Rasht
Province
Guilan
Postal code
۴۱۹۹۶۱۳۷۷۶
Phone
+98 933 611 7047
Email
mohammadalghosi9@gmail.com

Person responsible for scientific inquiries

Contact
Name of organization / entity
University of Guilan
Full name of responsible person
Mohammad Alghosi
Position
PhD student
Latest degree
Master
Other areas of specialty/work
Sport Science
Street address
Faculty of Physical Education and Sports Sciences, University of Guilan Complex, Persian Gulf Highway (Km. 5 of Rasht-Qazvin Road), Rasht, Iran.
City
Rasht
Province
Guilan
Postal code
۴۱۹۹۶۱۳۷۷۶
Phone
+98 933 611 7047
Email
mohammadalghosi9@gmail.com

Person responsible for updating data

Contact
Name of organization / entity
University of Guilan
Full name of responsible person
Mohammad Alghosi
Position
PhD student
Latest degree
Master
Other areas of specialty/work
Sport Science
Street address
Faculty of Physical Education and Sports Sciences, University of Guilan Complex, Persian Gulf Highway (Km. 5 of Rasht-Qazvin Road), Rasht, Iran.
City
Rasht
Province
Guilan
Postal code
۴۱۹۹۶۱۳۷۷۶
Phone
+98 933 611 7047
Email
mohammadalghosi9@gmail.com

Sharing plan

Deidentified Individual Participant Data Set (IPD)
Yes - There is a plan to make this available
Study Protocol
Yes - There is a plan to make this available
Statistical Analysis Plan
Undecided - It is not yet known if there will be a plan to make this available
Informed Consent Form
Yes - There is a plan to make this available
Clinical Study Report
Yes - There is a plan to make this available
Analytic Code
Undecided - It is not yet known if there will be a plan to make this available
Data Dictionary
Not applicable
Title and more details about the data/document
Some of the images used in the study will be corrupted.
When the data will become available and for how long
From 01/03/2026 to 6 months later
To whom data/document is available
Researcher
Under which criteria data/document could be used
An official email should be used to contact the corresponding author.
From where data/document is obtainable
corresponding author.
What processes are involved for a request to access data/document
official email
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