Acute changes in muscle thickness and pennation angle in response to work-matched concentric and eccentric isokinetic exercise.
Acute changes in muscle architecture influenced by muscle swelling might be associated with chronic adaptations to resistance exercise, including skeletal muscle growth. Concentric (CON) and eccentric (ECC) muscle actions both play a role in hypertrophic processes, but the influence of each on acute indices of muscle swelling (i.e., muscle thickness (MT) and pennation angle (PA)) remains relatively unknown. Therefore, this study compared the acute changes in MT and PA in response to work-matched CON versus ECC isokinetic exercise. Twelve university-aged students performed 2 bouts of maximal isokinetic knee extensions at 120°·s-1 on the same day: 50 CON followed by a work-matched ECC bout (∼5000 J; 28 ± 5 reps) with the contralateral limb. Ultrasound images were captured from the middle and distal sites of the vastus lateralis before and immediately after each exercise bout. From these images, MT and PA were measured. Middle and distal MT (11% and 14%, respectively; p < 0.001) and middle PA (39%, p < 0.001) increased only after CON. In addition, changes in MT were strongly related to the amount of total work performed (r = 0.76) during CON. Our results suggest that when the workload is matched between CON and ECC muscle actions performed at a moderate velocity, CON actions seem to be a more potent stimulus for inducing acute changes in MT and PA.
['Vieira|Amilton|A|', 'Blazevich|Anthony|A|', 'Souza|Nuno|N|', 'Celes|Rodrigo|R|', 'Alex|Savio|S|', 'Tufano|James J|JJ|', 'Bottaro|Martim|M|']
D000222:Adaptation, Physiological D015444:Exercise D005260:Female D006801:Humans D008297:Male D009119:Muscle Contraction D053580:Muscle Strength D053581:Muscle Strength Dynamometer D052097:Quadriceps Muscle D055070:Resistance Training D013997:Time Factors D014463:Ultrasonography D055815:Young Adult
muscle architecture muscle swelling resistance exercise ultrasound architecture musculaire dynamomètre isokinétique exercice contre résistance gonflement musculaire isokinetic dynamometer ultrasonographie