Eccentric and Trunk Stability Exercise Program Effects in Young Soccer Players

Effects of an 8-week Eccentric and Trunk Stability Exercise Program on Muscle Strength and Postural Stability in U19 Elite Soccer Players

The purpose of the present study is to investigate the effects of an in-season mixed training program on several physiological parameters of soccer players. Twenty-one U19 elite soccer players recruited and randomly assigned to either an 8-week specific training experimental group or a control group. The program will include an eccentric hamstring exercise, static balance exercises and core muscles strengthening exercises. Isokinetic hamstring and quadriceps strength, single leg static balance and lumbopelvic stability will be measured prior and after the intervention.

Study Overview

• Status: Completed
• Conditions: Muscle Strength; Postural Balance
• Intervention / Treatment: Other: Sliding leg curl; Other: Balance training; Other: Core stability

Detailed Description

A total of 123 male Under-19 (U19) players from several soccer teams were initially invited for participation in the study after signing informed consent forms. following a second contact with the participants, questionnaire forms with inclusion and exclusion criteria were send for completion.

Based on their self-report and a clinical examination by a health professional, of the 103 players, 42 did not meet the inclusion criteria, while 12 players did not participate for personal reasons. Of the remaining 69 players, 48 players were excluded, including 3 players reporting an anterior cruciate ligament reconstruction, 14 because of lower extremity injury led to more than two weeks absence from training and 10 players because of secondary injuries or health problems that led to loss of training the past 3 months.

A neutral, blinded investigator with no further involvement in the study was responsible for randomized allocation of participants in two groups. All training sessions in the training group will be supervised by a fitness coach, who will ensure that the exercises are performed according to protocol.

• Study Type: Interventional
• Enrollment (Actual): 21
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Greece
  • Serres, Greece, 62110
    • Laboratory of Neuromechanics, Department of physical education and sport sciences, Aristotle University of Thessaloniki

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 16 years to 19 years (ADULT, CHILD)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: Male

Description

Inclusion Criteria:

• 16 to 19 years old soccer players
• Trained at least 3 times and played 1 match weekly, the past 4 years
• Healthy
• Free from muscle injuries in the 6 months prior to the study

Exclusion Criteria:

• History of anterior cruciate ligament rupture
• History of ankle, hip or knee injury with duration at least 1 week, in the 3 months prior to the study
• Muscle injury with duration at least 1 week, in the 3 months prior to the study
• Any reason resulting in 2 weeks loss of training the preceding 6 months
• Involvement in hamstring strengthening, core stability or balance training program in the 6 months prior to the study

Study Plan

How is the study designed?

Design Details

• Primary Purpose: BASIC_SCIENCE
• Allocation: RANDOMIZED
• Interventional Model: PARALLEL
• Masking: DOUBLE

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
EXPERIMENTAL: Training group; For the balance exercise the participants will perform one-legged stance of certain duration, on a stable surface. For the sliding leg curl exercise the participants lay supine on a mat, wearing only socks in order to create a slippery surface between their heels and the gym floor. The player begins by extending the hip and having the working leg on knee flexion. The contralateral limb is on hip flexion and knee flexion. The base of support is the shoulder blades, the elbows and the heel of the working leg. After assuming this position, the player begins to extend the knee, as slowly as possible, resisting the low friction properties of the ground. The core stability program consists of front plank, side planks, supine bridge, leg lowering and superman exercise. These exercises will be performed at the end of the training session, in contrast to the balance and hamstring exercises which will be executed before the training session.	Other: Sliding leg curl; The exercise protocol consists of the following sets and repetitions Week 1- 2 sessions with 2 sets of 6 repetitions Week 2- 2 sessions with 3 sets of 6 repetitions Week 3- 2 sessions with 4 sets of 6 repetitions Week 4- 2 sessions with 4 sets of 8 repetitions Week 5- 2 sessions with 4 sets of 10 repetitions Week 6- 2 sessions with 4 sets of 10 repetitions Week 7- 2 sessions with 4 sets of 8 repetitions Week 8- 2 sessions with 4 sets of 8 repetitions; Other: Balance training; The exercise protocol consists of 2 sessions/week with 4 sets of 30'' single stance. Week 1 and 2- 1 set of 30'' single leg stance and 3 sets of 30'' single leg stance and ball kicks with contralateral foot Week 3 and 4- 2 sets of 30'' single leg stance while moving the ball around the leg with the contralateral foot and 2 sets of 30'' single leg stance, moving a ball around the knee with hands and kicking a ball with contralateral foot Week 5 and 6- 2 sets of 30'' single leg stance while giving and receiving hand passes with medicine ball (in couples) and 2 sets of 30'' single leg stance with perturbations (in couples) Week 7 and 8- Same as week 5 and 6 with extra 15" in each repetition; Other: Core stability; The exercise protocol consists of the following sets and repetitions Week 1 and 2- 3 sets of 30'' front plank, 3 sets of 20'' side plank, 2 sets of 30'' superman, 2 sets of 30'' supine bridge and 2 sets of 10 repetitions leg lowering exercise Week 3 and 4- increasing difficulty in 2 of the sets Week 5 and 6- adding 1 more set at each exercise Week 7 and 8- adding 15" in each repetition
NO_INTERVENTION: Control group; The participants in this group will follow only the usual training program

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Peak concentric and eccentric torque of hamstrings and quadriceps	Peak torque (N.m) is measured using isokinetic dynamometer at each angular velocity (30°·s-1, 180°·s-1, 240°·s-1).	Change from baseline assessment at 8 weeks
Total sway of the center of pressure (CoP)	This is defined as the average distance (mm) of the CoP from the reference lines and the amplitude is its standard deviation	Change from baseline assessment at 8 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Angle at peak torque of hamstrings and quadriceps	The angle at which peak torque of hamstrings and quadriceps muscles was achieved, at each angular velocity, measured in degrees (°)	Change from baseline assessment at 8 weeks
Conventional hamstrings to quadriceps ratio	This is calculated by dividing peak isokinetic concentric hamstring strength by the peak isokinetic concentric quadriceps strength, at the same angular velocity	Change from baseline assessment at 8 weeks
Dynamic hamstrings to quadriceps ratio	This is calculated by dividing peak isokinetic eccentric hamstring strength by the peak isokinetic concentric quadriceps strength, at the same angular velocity	Change from baseline assessment at 8 weeks
Mixed hamstrings to quadriceps ratio	This is calculated by dividing peak isokinetic eccentric hamstring strength at 30°·s-1 by the peak isokinetic concentric quadriceps strength at 240°·s-1	Change from baseline assessment at 8 weeks
Average speed of CoP	This reflects the amplitude and frequency of CoP movements and is calculated as the total length of the path of CoP divided by the test trial time (mm·s-1 )	Change from baseline assessment at 8 weeks

Collaborators and Investigators

• Sponsor: Konstantinos Dafkou
• Investigators: Principal Investigator: Konstantinos Dafkou, Laboratory of Neuromechanics, Aristotle University of Thessaloniki

Study record dates

Study Major Dates

• Study Start (ACTUAL): February 15, 2020
• Primary Completion (ACTUAL): June 30, 2020
• Study Completion (ACTUAL): July 5, 2020

Study Registration Dates

• First Submitted: March 29, 2020
• First Submitted That Met QC Criteria: March 29, 2020
• First Posted (ACTUAL): April 1, 2020

Study Record Updates

• Last Update Posted (ACTUAL): July 16, 2020
• Last Update Submitted That Met QC Criteria: July 15, 2020
• Last Verified: July 1, 2020

More Information

Terms related to this study

• Other Study ID Numbers: ERC-005/2020

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No