Recovery Kinetics Following Change of Direction Training
Condition: Skeletal Muscle Damage
Study type: Interventional

Summary: 
      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.
    

Detailed description: 
      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.
    

Intervention name(s): COD45; COD90
Intervention type(s): Other; Other
Intervention description(s): 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
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: None (Open Label)
Primary purpose: Other
Keywords: change of direction training; recovery; soccer; performance