Effects of the Football+ warm-up program on kinematics and kinetics related to anterior cruciate ligament (ACL) injury during single-leg landing in young male soccer players
The aim of the present study was to determine the effect of a 10-week Football+ warm-up program on kinematics and kinetics related to ACL injury in the single-leg landing-jump task and lower limb performance in young amateur soccer players under 23 years of age in Isfahan.
Design
Clinical trial with pretest and posttest design with two parallel groups (intervention group and control group), single-blind, randomization with an allocation ratio of 1:1 on 46 soccer players aged 15 to 21 years who were randomly divided into one of the two intervention groups and the control group through a computer randomization program.
Settings and conduct
Testing Locations:
- Rehabilitation School Laboratory, Isfahan University of Medical Sciences
- Sports Science Laboratory, University of Isfahan
Single-leg landing test from a 30 cm box
Static and dynamic Y-balance test
Isokinetic strength test
Single-leg triple hop test
Training Intervention:
Intervention group: 10-week Football+ Warm-up Program (3 sessions/week, 20–30 min/session)
- Control group: their usual warm-up program.
Post-Testing:
- All tests were repeated after 10 weeks
Participants/Inclusion and exclusion criteria
Inclusion criteria: Male players aged 15-21 years, no history of ACL injury, no history of lower limb surgery in the past year, three soccer practice sessions per week.
Exclusion criteria: Visible lower limb and trunk abnormalities, failure to adhere to 80% of training sessions.
Intervention groups
1. Intervention group (Football+ warm-up Training ,a recently published evidence-based warm-up program to reduce injuries and improve performance in soccer players.
2. Control Group (performed their usual warm-up exercises).
Main outcome variables
Kinematics of the hip and knee joints in the sagittal and frontal planes; kinetics and moments applied to the knee; and ground reaction forces
General information
Reason for update
Acronym
IRCT registration information
IRCT registration number:IRCT20250528065947N1
Registration date:2026-04-25, 1405/02/05
Registration timing:prospective
Last update:2026-04-25, 1405/02/05
Update count:0
Registration date
2026-04-25, 1405/02/05
Registrant information
Name
Arzhang Kiani
Name of organization / entity
Country
Iran (Islamic Republic of)
Phone
+98 61 4363 2597
Email address
arzhangkian@gmail.com
Recruitment status
recruiting
Funding source
Expected recruitment start date
2026-08-21, 1405/05/30
Expected recruitment end date
2026-12-26, 1405/10/05
Actual recruitment start date
empty
Actual recruitment end date
empty
Trial completion date
empty
Scientific title
Effects of the Football+ warm-up program on kinematics and kinetics related to anterior cruciate ligament (ACL) injury during single-leg landing in young male soccer players
Public title
The Effect of Football+ warm-up program on ACL Injury Risk Factors
Purpose
Prevention
Inclusion/Exclusion criteria
Inclusion criteria:
Participants must sign and submit an informed consent form in accordance with the ethics committee format
For players under the age of 18, the informed consent form must be signed and approved by their parents
Male players aged between 15 and 21 years
No participation in similar injury prevention programs
No history of ACL injury
No acute lower limb injury in the past 6 months
No history of lower limb surgery in the past year
No history of neurological disorders
Participation in three football training sessions per week
Exclusion criteria:
Failure to provide the informed consent form
History of ACL injury
Undergoing lower limb surgery within the past year
Age
From 15 years old to 21 years old
Gender
Male
Phase
N/A
Groups that have been masked
Outcome assessor
Data analyser
Sample size
Target sample size:
46
Randomization (investigator's opinion)
Randomized
Randomization description
In this study, participants will be randomly assigned to one of two groups (the intervention group: 10 weeks of Football+ warm-up training and the control group: usual training) using the website www.sealedenvelope.com. Randomization will be conducted using a block randomization method with a 1:1 allocation ratio. To ensure allocation concealment, the randomization code will remain concealed from the time of all baseline measurements until the participant enters the trial. For allocation concealment, randomization will be implemented via a computer-generated sequence, using opaque, sequentially numbered, and sealed envelopes. a card inside each envelope will indicate the group assigned to each participant.
Blinding (investigator's opinion)
Single blinded
Blinding description
The present study will employ a single-blind design, in which only the outcome assessors are blind to their group allocation. Outcome measures are assessed at baseline and post-test by a blinded assessor who remains unaware of both the study hypothesis and methodology.
Placebo
Not used
Assignment
Parallel
Other design features
Based on the nature of the subject and its execution, this study is quasi-experimental and applied, using a pre-test and post-test design with two parallel groups. Using G*Power software (version 3.1.9.7, University of Kiel, Germany), the sample size calculation for a 2×2 mixed design, focusing on the time × group interaction effect, shows that 15 participants per group (30 in total) are needed to achieve 80% statistical power with an alpha of 0.05, beta of 0.20, and an effect size of 0.06. To prevent the possibility of subject dropout and to improve statistical power, 23 participants per group (totaling 46) will be considered.
Secondary Ids
empty
Ethics committees
1
Ethics committee
Name of ethics committee
Research Ethics Committees of University of Isfahan
Street address
Postal Code: 8174673441, University of Isfahan, Esfahan, Iran Azadi Square, ,
City
Esfahan
Province
Isfehan
Postal code
8174673441
Approval date
2026-02-21, 1404/12/02
Ethics committee reference number
IR.UI.REC.1404.278
Health conditions studied
1
Description of health condition studied
Effects of the Football+ warm-up program on kinematics and kinetics related to anterior cruciate ligament (ACL) injury during single-leg landing in young male soccer players
ICD-10 code
ICD-10 code description
Primary outcomes
1
Description
Biomechanical Risk Factors Associated with Anterior Cruciate Ligament Injury
Timepoint
At baseline (pre-intervention) and one week post-training.
Method of measurement
Single-leg landing test from a 30 cm box to assess lower limb kinematics and kinetics
2
Description
Lower extremity performance
Timepoint
At baseline (pre-intervention) and one week post-training.
Method of measurement
Static and dynamic Y balance test
Secondary outcomes
1
Description
Isokinetic strength of the quadriceps and hamstrings
Timepoint
At the beginning of the study (pre-test) and then at the end of the study (post-test)
Method of measurement
Isokinetic dynamometer (Biodex Multi-joint System 3, Biodex Medical Systems, USA)
Intervention groups
1
Description
Intervention Group (Football+ Warm-up training): This is a football-specific injury prevention program recently designed, developed, and implemented by the Movement and Exercise Science group at the Dortmund Institute of Sport Science, in collaboration with Borussia Dortmund Football Club. The program is delivered as a structured warm-up protocol comprising a series of football-specific exercises aimed at both enhancing movement performance and targeting injury risk factors. Designed to ensure high compliance and adherence within football organizations, the Football+ program consists of three components: 1) Foundation, including running and strengthening exercises; 2) Ball-based training and small-sided games (SSGs); and 3) Explosive performance, including plyometric, agility, and speed drills. The Football+ exercises are categorized into three difficulty levels and are modified and adapted every 4 to 6 weeks based on the players' abilities and progress. Each session lasts approximately 20 to 30 minutes and is performed at least twice per week
Category
Prevention
2
Description
Control group: Control (in this study, the control group will perform their usual and common exercises, including running, static and dynamic stretching exercises)
Category
Prevention
Recruitment centers
1
Recruitment center
Name of recruitment center
Isfahan City Football Committee
Full name of responsible person
Mustafa Davoodi
Street address
Bozorgmehr Street, Sharif Al-Nasab Alley
City
Esfahan
Province
Isfehan
Postal code
814658888
Phone
+98 903 399 4385
Email
Arzhangkian@gmail.com
Sponsors / Funding sources
1
Sponsor
Name of organization / entity
The University of Isfahan
Full name of responsible person
Hamidreza Mirsafian
Street address
Postal Code: 8174673441, University of Isfahan, Isfahan, IranAzadi Square,
City
Esfahan
Province
Isfehan
Postal code
8174673441
Phone
+98 913 214 2319
Email
h.mirsafian@spr.ui.ac.ir
Grant name
Grant code / Reference number
Is the source of funding the same sponsor organization/entity?
Yes
Title of funding source
The University of Isfahan
Proportion provided by this source
5
Public or private sector
Public
Domestic or foreign origin
Domestic
Category of foreign source of funding
empty
Country of origin
Type of organization providing the funding
Academic
Person responsible for general inquiries
Contact
Name of organization / entity
University of Isfahan
Full name of responsible person
Arzhang Kiani
Position
PHD student
Latest degree
Master
Other areas of specialty/work
Sport Sciences
Street address
university of Isfahan Azadi Square Isfahan, Iran
City
اصفهان
Province
Isfehan
Postal code
8174673441
Phone
+98 916 534 6925
Email
Arzhangkian@gmail.com
Person responsible for scientific inquiries
Contact
Name of organization / entity
The University of Isfahan
Full name of responsible person
Arzhang Kiani
Position
PHD Student
Latest degree
Master
Other areas of specialty/work
Sport Sciences
Street address
University of Isfahan Azadi Square Isfahan, Iran
City
Esfahan
Province
Isfehan
Postal code
8174673441
Phone
+98 916 534 6925
Email
Arzhangkian@gmail.com
Person responsible for updating data
Contact
Name of organization / entity
University of Isfahan
Full name of responsible person
Arzhang Kiani
Position
PHD Student
Latest degree
Master
Other areas of specialty/work
Sport sciences
Street address
University of Isfahan Azadi Square Isfahan, Iran
City
Esfahan
Province
Isfehan
Postal code
8174673441
Phone
+98 916 534 6925
Email
Arzhangkian@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
Yes - There is 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
Not applicable
Data Dictionary
Not applicable
Title and more details about the data/document
"The data on primary outcomes can be shared
When the data will become available and for how long
"Two months after publication of the results"
To whom data/document is available
All interested parties, including researchers
Under which criteria data/document could be used
There are no other conditions
From where data/document is obtainable
The principal investigator of the study was contacted via email.
What processes are involved for a request to access data/document
They must send their request by email to the principal investigator