Comparison of the Agonist/Antagonist Tensional Balance of the Knee between Two Isokinetic Positions: A Pilot Study on a Sample of High-Level Competitive Soccer Players

Isokinetic knee dynamometry evolves towards more precise techniques, such as the calculation of the functional ratio. This study evaluated the influence of an intermediate hip position called the unified reclined position (URP) compared to the classic sitting position, (CSP) on hamstring eccentric PT values (H(exc30)) and conventional (H(con60)/Q(con60)) and functional (H(exc30)/Q(con60)) ratios. Twenty Spanish high-level competitive soccer players (20.4 ± 4.44 years) were evaluated in CSP and in URP. The hip angle in URP (44°) was determined with a passive extensibility test (quadriceps and hamstrings), looking for an agonist/antagonist tension balance. The following were performed: three repetitions (60°/s) and five repetitions (240°/s) in concentric quadriceps and hamstrings mode; and three repetitions (30°/s) in concentric and eccentric for the hamstrings. At 30°/s, the CSP presents higher values of maximal eccentric hamstring strength than URP, (Dom + N-Dom leg (Nm): CSP = 148.3 ± 19.5 vs. URP 143.5 ± 23.2); p = 0.086 (n.s.). The conventional relationship did not show data justifying the preference for URP over CSP (p = 0.86 (n.s.)). However, although the functional index did not show significant values (p = 0.97 (n.s.), it did show a greater number of subjects with imbalances measured in URP (five in URP vs. two in CSP). An assessment angle of the hip closer to sports reality seems to favor the use of the URP as a complementary method to the CSP. These data stimulate new studies using URP together with the classic protocol.