Recovery Kinetics Following Eccentric Exercise
Condition: Muscle Damage
Study type: Interventional

Summary: 
      The aim of this study will be to investigate the recovery kinetics of neuromuscular fatigue,
      muscle microtrauma indicators, performance and oxidative stress factors after three different
      exercise induced muscle damage (EIMD) protocols in adult Males. Also, this study will
      determine the comparison among three different eccentric protocols in neuromuscular fatigue,
      muscle microtrauma indicators, performance and oxidative stress factors. The eccentric
      protocols will be differentiated in training volume and specifically in the eccentric
      repetitions in isokinetic dynamometer.
    

Detailed description: 
      It is known that eccentric exercise induces muscle microtrauma. Also, eccentric type of
      exercise are associated with inflammatory response. The leukocytes and the immune cells
      during the phagocytosis process alter the redox status causing secondary muscle damage to the
      muscle tissue and also increase oxidative stress concentration. Despite of the existence of
      studies that examine the muscle damage indicators, inflammatory response, performance and
      neuromuscular fatigue and oxidative stress concentrations after eccentric exercise, however
      no studies are detected in order to compare the differences among three eccentric protocols.
      The eccentric protocols will be differentiated in training volume and specifically in the
      eccentric repetitions in isokinetic dynamometer. Specifically, a randomized, fourth-trial,
      cross-over, repeated measures design will be applied. Healthy male adults (age 18-30 years)
      will participate in the present study. Also, it is considered necessary that the participants
      will not suffer from any musculoskeletal injuries that will limit their ability to perform
      the exercise protocols. Also the participants will not be smokers and will not consume
      alcohol and nutritional supplements.

      In the first phase all participants will sign an informed consent form after they will be
      informed about all benefits and risks of this study and they will sign a recent historical of
      musculoskeletal injury or illness form. Subsequently, fasting blood samples will be collected
      by venipuncture using a disposable needle (20-gauge) in order to measure muscle damage
      markers (CK), inflammation markers (WBC) and oxidative stress markers (TBARS, PC, GSH, ΤΑC,
      CAT, UA). After, delayed onset muscle soreness (DOMS) in the knee flexors (KF) and extensors
      (KE) of both limbs, body weight (BW), height and body composition (DXA method) will be
      measured in the lab. Completing the first phase, participants will be instructed by a
      dietitian how to record a 5 days diet recalls estimating the energy intake during the trials
      will be the same. The knee range of motion (KJRM) will be determined by the use of a
      goniometer, 24 hours after (second phase). The counter movement jump (CMJ) will be evaluated
      on a force platform 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 data for each
      leg. During the CMJ will be measured the jump height (cm), the ground reaction force (N), the
      peak and mean power (W/kg), the vertical stiffness (Kvert, N/m/kg) and the peak rate of force
      development (RFD, N/s), while at the same time will be evaluated the change in peak and mean
      normalized EMG during the eccentric and concentric phases of the counter movement jump, for
      the vastus medialis (VM) and vastus lateralis muscles. Electromyography data will be
      collected wirelessly at 2.000 Hz using a Myon MA-320 EMG system. The peak eccentric and
      concentric isokinetic torque of the knee flexors and extensors, in both limbs will be
      evaluated on an isokinetic dynamometer at 60°/sec. Also, the isometric peak torque of the
      knee extensors will be evaluated at 65° in both limbs. Finally, Open-circuit spirometry will
      be utilized for assessment of maximal oxygen consumption (VO2max) using an automated online
      pulmonary gas exchange system via breath-by-breath analysis during a graded exercise testing
      on a treadmill.

      96 hours after, the participants are going to perform one of the three eccentric protocols
      randomly, on an isokinetic dynamometer. The eccentric protocol will be performed on a
      different limb for each trial. The ECC 75 trial will include 75 eccentric maximum repetitions
      (5 sets, 15 reps/set and recovery period: 30sec.) at 60°/sec. The ECC 150 trial will include
      150 eccentric maximum repetitions (10 sets, 15 reps/set and recovery period: 30sec.) at
      60°/sec. The ECC 300 trial will include 300 eccentric maximum repetitions (20 sets, 15
      reps/set and recovery period: 30sec.) at 60°/sec. The DOMS indicator in the knee flexors (KF)
      and extensors (KE) of both limbs and the KJRM will be evaluated immediately after each
      protocol. Also, the (CMJ) will be evaluated on a force platform 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 data for each leg. During the CMJ will be measured the
      jump height (cm), the ground reaction force (N), the peak and mean power (W/kg), the vertical
      stiffness (Kvert, N/m/kg) and the peak rate of force development (RFD, N/s), while at the
      same time will be evaluated the change in peak and mean normalized EMG during the eccentric
      and concentric phases of the counter movement jump, for the vastus medialis (VM) and vastus
      lateralis muscles. Electromyography data will be collected wirelessly at 2.000 Hz using a
      Myon MA-320 EMG system. In addition, the peak eccentric and concentric isokinetic torque of
      the knee flexors and extensors, in both limbs will be evaluated on an isokinetic dynamometer
      at 60o/sec. Also, the isometric peak torque of the knee extensors will be evaluated at 65o in
      both limbs. All the above markers will be evaluated 24, 48 and 192 hours post eccentric
      protocol, however at these time points, fasting blood samples (20ml) will be collected in
      order to estimate hematological and biochemical indicators. Α 2 - week washout period will be
      adapted among trials. After, the participants will perform the process until they complete
      the trials.
    

Intervention name(s): 75 eccentric contractions; 150 eccentric contractions; 300 eccentric contractions
Intervention type(s): Other; Other; Other
Intervention description(s): An acute bout of eccentric exercise will be performed on an isokinetic dynamometer, including 5 sets of 15 repetitions, with 30 sec rest intervals,at 60 degrees/sec.; An acute bout of eccentric exercise will be performed on an isokinetic dynamometer, including 10 sets of 15 repetitions, with 30 sec rest intervals,at 60 degrees/sec.; An acute bout of eccentric exercise will be performed on an isokinetic dynamometer, including 20 sets of 15 repetitions, with 30 sec rest intervals,at 60 degrees/sec.
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: None (Open Label)
Primary purpose: Basic Science
Keywords: muscle damage; oxidative stress; Eccentric exercise; Neuromuscular fatigue; Recovery