More Training, Less Trainability: True? A muscle Swelling Analysis

Background. It is still not clear what physiologically differentiates trained individu­als from untrained individuals regarding the ability to hypertrophy, with speculation that these individuals may present different swelling levels in response to the same training load. Objective. This study aimed to compare the response of muscular swelling between eight adults from the More Experienced Group (MEG) and eight participants from the Less Experienced Group (LEG). Methods. The swelling response in the biceps brachii muscle was assessed by measur­ing the variation in cross-sectional area at 50% of the arm length (pre vs post) using B-mode ultrasound through a paired t-test. This comparison was conducted after the completion of four sets to failure at 70% of the one maximum repetition test in the preacher barbell curl exercise. Additionally, the mean values for the maximum number of repetitions (MNR), time under tension (TUT), and the rate of perceived exertion (RPE) for the four sets were also compared using a paired t-test. Results. LEG exhibited greater muscle swelling compared to the MEG (22.59 ± 7.05%; 15.71 ± 5.40%, respectively: p < 0.001), although no significant differences were observed in MNR, TUT, and RPE. Conclusions. Experience level appears to influence the response of muscular swell­ing, indicating that individuals with less experience tend to have greater swelling than those with more experience in strength training. Thus, more trained individuals should seek to implement training strategies, such as an increase in training load, if maintain­ing muscular swelling is desired.