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.
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
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
DOUBLE
Enrollment
21
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
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
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
Laboratory of Neuromechanics, Department of physical education and sport sciences, Aristotle University of Thessaloniki
Serres, Greece
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).
Time frame: 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
Time frame: Change from baseline assessment at 8 weeks
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 (°)
Time frame: 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
Time frame: 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
Time frame: 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
Time frame: 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 )
Time frame: Change from baseline assessment at 8 weeks
This platform is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional.