The purpose of this study is to investigate the magnitude of changes in biomarkers of exercise-induced muscle damage following an acute bout of eccentric exercise of the knee extensors performed on an isokinetic dynamometer. Moreover, these biomarkers will be assessed at different time points after the initial intervention, checking the repeated bout effect phenomenon.
Volunteers will visit the laboratory a total of two times. During the first visit, in all participants will be assessed indirect markers of exercise-induced muscle damage (i.e., peak torque, delayed-onset muscle soreness, range of motion, rate of force development), blood parameters (i.e., creatine kinase and c-Reactive Protein), and muscle oxygenation using near infrared spectroscopy. Afterwards, participants will perform an eccentric exercise protocol for the knee extensors consisting of 5 sets of 15 maximal-intensity repetitions at an angular velocity of 60°/s. The second visit will be at different time points between participant, where the indirect mauls damage biomarkers will be reassessed before and after the same isokinetic eccentric exercise (i.e., 5 sets of 15 maximal-intensity repetitions at an angular velocity of 60°/s).
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
NONE
Enrollment
48
Eccentric exercise will be performed using an isokinetic dynamometer. It will be consisted of 5 set of 15 eccentric contraction of the knee extensors at an angular velocity of 60o/s. The intensity will be maximal voluntary.
Department of Physical Education and Sport Science, National and Kapodistrian University of Athens
Athens, Attica, Greece
Delayed onset muscle soreness
Pain will be assessed at baseline (before the eccentric exercise bout) and again at 48 hours (2 days) after the eccentric exercise bout.
Time frame: Baseline and 48 hours after the eccentric exercise bout.
Peak torque output
Peak torque will be assessed at baseline (before the eccentric exercise bout) and again at 48 hours (2 days) after the eccentric exercise bout.
Time frame: Baseline and 48 hours after the eccentric exercise bout.
Range of Motion
The free pain range of motion will be assessed at baseline (before the eccentric exercise bout) and again at 48 hours (2 days) after the eccentric exercise bout.
Time frame: Baseline and 48 hours after the eccentric exercise bout.
Muscle oxygenation
Using near infrared spectroscopy, the oxygenation of the knee extensors will be assessed at baseline (before the eccentric exercise bout) and again at 48 hours (2 days) after the eccentric exercise bout.
Time frame: Baseline and 48 hours after the eccentric exercise bout.
Creatine kinase
Creatine kinase will be assessed at baseline (before the eccentric exercise bout) and again at 48 hours (2 days) after the eccentric exercise bout.
Time frame: Baseline and 48 hours after the eccentric exercise bout.
Muscle thickness using ultrasound
Participants's knee extensors muscle thickness will be assessed at baseline (before the eccentric exercise bout) and again at 48 hours (2 days) after the eccentric exercise bout.
Time frame: Baseline and 48 hours after the eccentric exercise bout.
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