Abstract
Purpose: This study aimed to examine the variations in the velocity of contraction (Vc) assessed via tensiomyography (TMG), vertical jumping ability, and sprinting speed induced by four different exercise protocols (i.e., strength, sprint, plyometric, and technical training sessions) in fourteen male National Team rugby players (age: 21.8 ± 2.6 years; weight: 83.6 ± 8.5 kg; height: 177.4 ± 6.7 cm). Methods: Physical tests were conducted immediately pre- and post- four distinct workouts, in the following order: (1) TMG in the rectus femoris (RF) and biceps femoris (BF) muscles; (2) squat and countermovement jumps (SJ and CMJ); and (3) 30-m sprint velocity. To analyze the differences in the assessed variables before and after each training session, the differences based on magnitudes were calculated. Results: After strength and plyometric workouts, the players presented possible to almost certain impairments in sprint and jump performance and in the Vc RF (effect sizes varying from 0.26 to 0.64). After the sprint training session, possible to very likely decreases were observed in the SJ, 30-m sprint, and Vc BF (effect sizes varying between 0.21 and 0.44). In contrast, after the technical training, athletes demonstrated a possible increase in the SJ and Vc in both muscles examined (effect sizes varying from 0.13 to 0.20). Conclusions: The main finding of this research is that, for the vast majority of results, the direction of changes observed in the Vc were the same as those observed in performance assessments. This suggests that the Vc might be used as a sensitive marker of acute variations in speed and power performance of elite team-sport athletes.
