This study aims at investigating the recovery kinetics of skeletal muscle damage, neuromuscular fatigue and performance following a single change of direction (COD) training session in competitive soccer players. The impact of COD degrees will be also examined by comparing a 45o vs. 90o COD training session. Ten male soccer players will perform a COD45 \[A single training session including 2x(10x \~27.6m) sprints with two 45o COD in each sprint\], a COD90 \[A single training session including 2x(10x \~21.2m) sprints with two 90o COD in each sprint\] and a Control trial (No intervention included, only daily measurements) in randomized, repeated measures, crossover design. Assessments related to skeletal muscle damage, neuromuscular fatigue and performance will be performed prior to training session and daily for three consecutive days post-training, in each trial.
Ten male soccer players will be included in this study. Participants will be initially informed about the aim of study as well as the associated risks and benefits and subsequently will provide their signed consent form. At baseline, they will undergo assessment of their anthropometrics (i.e. body mass and body height), body composition (by DXA), physical conditioning status \[maximal oxygen consumption (VO2max), Yo-Yo Intermittent Endurance test level 2 and Yo-Yo Intermittent Recovery test level 2\] and daily dietary intake. Thereafter, they will participate in two experimental trials and one control trial in a randomized, crossover, repeated measures design: i) COD45: Participants in this trial will perform a COD training session consisted of 2 sets of 10 x \~27.6m sprints with two 45o COD in each sprint and a resting period of 16 sec and 2:20 min between sprints and sets, respectively, ii) COD90: Participants in this trial will perform a COD training session consisted of 2 sets of 10 x \~21.2m sprints with two 90o COD in each sprint and a resting period of 16 sec and 2:20 min between sprints and sets, respectively, iii) Control: Participants in this trial will only participate in daily assessments to control for day to day variability in the depended variables (they will not receive any intervention). Prior to each trial, participants will provide a resting blood sample (for the determination of blood lactate, white blood cell count and creatine kinase activity) and undergo assessment of their delayed onset of muscle soreness (DOMS), maximal voluntary isometric contraction (MVIC), countermovement jump \[will be assessed using two force platforms at 1000 Hz and electromyography instrumentation (EMG)\], isokinetic peak torque of knee extensors and flexors (will be assessed on an isokinetic dynamometer), agility (will be assessed using the Illinois test), 10m and 30m sprint time (will be assessed by using light cells) and repeated sprint ability (5x30m sprints will be performed with 25 sec rest in-between). In COD45 and COD90 experimental trials, a blood sample will be collected immediately post-training for the determination of blood lactate concentration while assessment of DOMS, MVIC and countermovement jump will be performed at 1, 2 and 3 hours post-training. In all trials assessment of DOMS, MVIC, countermovement jump (CMJ), isokinetic peak torque, agility and sprinting performance as well as determination of creatine kinase activity and white blood cell count will be performed at 24, 48 and 72 hours post-training. A 7-day wash out period will applied between trials.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
OTHER
Masking
NONE
Enrollment
10
Participants will perform 2 sets of 10 sprints. The total distance for each sprint will be 27.6 meters and will include two changes of direction of 45 degrees. The recovery time will be 16 seconds between sprints and 2.20 minutes between sets
Participants will perform 2 sets of 10 sprints. The total distance for each sprint will be 21.2 meters and will include two changes of direction of 90 degrees. The recovery time will be 16 seconds between sprints and 2.20 minutes between sets
SMART LAB, Department of Physical Education and Sports Science, University of Thessaly.
Trikala, Greece
SmArT LABORATORY, SCHOOL OF PHYSICAL EDUCATION & SPORTS SCIENCES, UNIVERSITY OF THESSALY
Trikala, Greece
Change in creatine kinase activity
Creatine kinase activity will be measured in plasma
Time frame: At baseline, at 24, 48 and 72 hours after change of direction training session
Change in white blood cell count
White blood cell count will be measured by using an automatic blood analyzer
Time frame: At baseline, at 24, 48 and 72 hours after change of direction training session
Change in delayed onset of muscle soreness
Muscle soreness will be assessed by palpation of the muscle belly and the distal region
Time frame: At baseline, at 1, 2, 3, 24, 48 and 72 hours after change of direction training session
Change in isometric peak torque
Isometric peak torque will be assessed on an isokinetic dynamometer
Time frame: At baseline, at 1, 2, 3, 24, 48 and 72 hours after change of direction training session
Change in fatigue index of maximal voluntary isometric contraction during 10 seconds
Fatigue rate will be determined by calculating the percent drop of peak torque between the first and the last three seconds of a 10-second maximal isometric contraction
Time frame: At baseline, at 1, 2, 3, 24, 48 and 72 hours after change of direction training session
Change in isokinetic peak torque of knee extensors
Isokinetic peak torque will be assessed on an isokinetic dynamometer in both limbs
Time frame: At baseline, at 24, 48 and 72 hours after change of direction training session
Change in isokinetic peak torque of knee flexors
Isokinetic peak torque will be assessed on an isokinetic dynamometer in both limbs
Time frame: At baseline, at 24, 48 and 72 hours after change of direction training session
Change in countermovement jump height
Countermovement jump height will be assessed by using two force platforms at 1000 Hz, with each foot in parallel on the two platforms providing a separate yet time-synchronized measurement of the jump height for each leg
Time frame: At baseline, at 1, 2, 3, 24, 48 and 72 hours after change of direction training session
Change in ground reaction force during countermovement jump
Ground reaction force will be assessed by using two force platforms at 1000 Hz, with each foot in parallel on the two platforms providing a separate yet time-synchronized measurement of the jump height for each leg
Time frame: At baseline, at 1, 2, 3, 24, 48 and 72 hours after change of direction training session
Change in peak power during countermovement jump
Peak power will be assessed using two force platforms at 1000 Hz, with each foot in parallel on the two platforms providing a separate yet time-synchronized measurement of the jump height for each leg
Time frame: At baseline, at 1, 2, 3, 24, 48 and 72 hours after change of direction training session
Change in mean power during countermovement jump
Mean power will be assessed using two force platforms at 1000 Hz, with each foot in parallel on the two platforms providing a separate yet time-synchronized measurement of the jump height for each leg
Time frame: At baseline, at 1, 2, 3, 24, 48 and 72 hours after change of direction training session
Change in vertical stiffness during countermovement jump
Vertical stiffness will be assessed using two force platforms at 1000 Hz, with each foot in parallel on the two platforms providing a separate yet time-synchronized measurement of the jump height for each leg
Time frame: At baseline, at 1, 2, 3, 24, 48 and 72 hours after change of direction training session
Change in peak rate of force development during countermovement jump
Peak rate of force development will be assessed using two force platforms at 1000 Hz, with each foot in parallel on the two platforms providing a separate yet time-synchronized measurement of the jump height for each leg
Time frame: At baseline, at 1, 2, 3, 24, 48 and 72 hours after change of direction training session
Change in peak normalized electromyography (EMG) during the eccentric and concentric phases of the countermovement jump
EMG data will be collected wirelessly at 2000 Hz using a Myon MA-320 EMG system (Myon AG, Switzerland) for the vastus lateralis, biceps femoris, gastrocnemius and gluteus maximus muscles.
Time frame: At baseline, at 1, 2, 3, 24, 48 and 72 hours after change of direction training session
Change in mean normalized electromyography (EMG) during the eccentric and concentric phases of the countermovement jump
EMG data will be collected wirelessly at 2000 Hz using a Myon MA-320 EMG system (Myon AG, Switzerland) for the vastus lateralis, biceps femoris, gastrocnemius and gluteus maximus muscles.
Time frame: At baseline, at 1, 2, 3, 24, 48 and 72 hours after change of direction training session
Change in repeated sprint ability
Repeated sprint ability will be tested using 5x30 m sprints with 25 seconds rest in-between
Time frame: At baseline, at 24, 48 and 72 hours after change of direction training session
Change in sprint time of 10m
10m sprint time will be assessed using light cells
Time frame: At baseline, at 24, 48 and 72 hours after change of direction training session
Change in sprint time of 30m
30m sprint time will be assessed using light cells
Time frame: At baseline, at 24, 48 and 72 hours after change of direction training session
Change in agility
Agility will be assessed using the illinois agility test.
Time frame: At baseline, at 24, 48 and 72 hours after change of direction training session
Change in field activity during the change of direction training session
Field activity will be continuously monitored during the change of direction training session by using global positioning system (GPS)
Time frame: During the change of direction training session
Change in heart rate during the change of direction training session
Heart rate will be continuously monitored during the change of direction training session by using heart rate monitors.
Time frame: During the change of direction training session
Change in blood lactate concentration
Blood lactate will be measured using a lactate plus system
Time frame: At baseline and immediately post change of direction training session
Body mass
Body mass will me measured on a beam balance with stadiometer
Time frame: At baseline
Body height
Body height will me measured on a beam balance with stadiometer
Time frame: At baseline
Body fat
Body fat will be assessed by using Dual-emission X-ray absorptiometry
Time frame: At baseline
Lean body mass
Lean body mass will be assessed by using Dual-emission X-ray absorptiometry
Time frame: At baseline
Maximal oxygen consumption (VO2max)
VO2max will be measured by open circuit spirometry via breath by breath method
Time frame: At baseline
Yo-Yo Intermittent Endurance Test level 2 performance
Time frame: At baseline
Yo-Yo Intermittent Recovery Test level 2 performance
Time frame: At baseline
Dietary intake
Dietary intake will be assessed over a 7-day period by using diet recalls
Time frame: At baseline
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