Supervisors info:
Πασχάλης Β., Αναπληρωτής Καθηγητής, ΣΕΦΑΑ, ΕΚΠΑ
Γελαδάς Ν., Καθηγητής, ΣΕΦΑΑ, ΕΚΠΑ
Τερζής Γ., Καθηγητής, ΣΕΦΑΑ, ΕΚΠΑ
Summary:
This study aimed to investigate the effect of exercise-induced muscle damage (EIMD) on muscle and cerebral oxygenation after an acute bout of eccentric exercise and its impact on the muscle architecture of vastus lateralis. Twelve healthy men (n=12, age 25.2 ± 4.8 years, mass 79.4 ± 10.2kg, height 1.80 ± 0.13, and BMI 24.5 ± 2.2) performed five sets of ten repetitions of unilateral eccentric exercise on a 45-degree leg press at an intensity of 70% of one maximum concentric contraction. Twenty-four hours prior and 48 hours after eccentric exercise, muscle and cerebral oxygenation (Δ[H2Ob], Δ[HHb], Δ[tHb], and TSI%) were monitored with near-infrared spectroscopy at rest, during 5 and 30 seconds of maximum isometric contraction on a modified force platform. Isometric leg press rate of force development (RFD) at 80,100 and 150ms and maximum concentric contraction were also assessed. In addition, the architectural structure of vastus lateralis was evaluated through ultrasound imaging. Two days after eccentric exercise, muscle pain increased significantly (p <0.01) while RFD and one maximum repetition decreased (p<0.01). There was no change in the oxygenation indices of the vastus lateralis in the resting state as well at 30 seconds of maximum isometric contraction(p> 0.05). However, the time by condition interaction of deoxygenated Δ[HHb] and total hemoglobin Δ[tHb] was found to be significantly reduced during the 5s maximum isometric contraction. No significant differences were found in the pennation angle, fascicle length, and muscle thickness after the intervention and between conditions (p>0.05). Nevertheless, the cross-sectional area of the muscle was significantly increased (9%) for the experimental leg after the eccentric exercise (p<0.05). In conclusion, 48 hours after unilateral eccentric exercise, muscle and cerebral oxygenation did not change at rest and 30 seconds of maximum isometric contraction. However, there was a significant drop in deoxygenated Δ[HHb] and total hemoglobin Δ[tHb] at 5 seconds of maximum isometric contraction, suggesting a disturbance in either oxygen availability or oxygen consumption. In addition, there was a significant increase in the cross-sectional area after the intervention without changing pennation angle, fascicle length, and muscle thickness.
