The Vertical Force-velocity Profile in Male Under-20 National Team Rugby XV Union Players

Purpose: The main aim of the present study was to describe the Vertical Force-velocity (F-v) profile in male Under-20 (U-20) national team rugby XV union players. Also, as a secondary aim, we proposed to establish the relationships between anthropometric variables with F-v profile parameters. Methods: Ten elite rugby union players from Uruguayan National male U-20 team [age: 18.9 ± 0.3 years; body mass: 90.03 ± 9.09 kg; body mass index (BMI): 26.28 ± 1.33 kg·m-2] were assessed in their force-velocity profile employing squat jump (SJ) with incremental loads. Moreover, we performed correlations between anthropometric variables [height, body mass, BMI, lower-limb length fully extended position (LL length), starting position of the jump (hs), and vertical push-off distance (hpo)] with the F-v profile variables [theoretical maximal force (F0), theoretical maximal velocity (V0), maximal mechanical power output (Pmax), deviation from the optimal profile (Dev), force-velocity imbalance (FVimb), SJ height (SJ0 h) and SJ power (SJ0 P)]. Results: Among the 10 rugby union players evaluated, 7 of them presented a force deficit, 2 were well balanced, and only one presented a velocity deficit. Thus, five athletes presented a high force deficit (37-52%), 2 a low force deficit (64 and 66%), 2 were well balanced (95 and 96%) and only one showed a low velocity deficit (136%). Furthermore, we found large to very large significant correlations between hs with F0, V0, FVimb and Dev (r > 0.6; p < 0.05). Additionally, we found a very large significant correlation between SJ0 h with Pmax (r = 0.757; p = 0.011). Conclusion: Male U-20 union rugby players presented force imbalance, which could suggest a greater emphasis of maximal strength performance for this sample.