Effects of Different Stretching Modalities on the Antagonist and Agonist Muscles on Isokinetic Strength and Vertical Jump Performance in Young Men

Montalvo, S, Gonzalez, MP, Dietze-Hermosa, MS, Martinez, A, Rodriguez, S, Gomez, M, Ibarra-Mejia, G, Tan, E, and Dorgo, S. Effects of different stretching modalities on the antagonist and agonist muscles on isokinetic strength and vertical jump performance in young men. J Strength Cond Res XX(X): 000-000, 2024-Exercise warm-up may include static or dynamic stretching, impacting performance differently. This study investigated the effects of various stretching protocols on isokinetic strength, muscular activity, and vertical jump performance. Sixteen subjects, divided evenly between trained and untrained groups, underwent 8 distinct stretching conditions in random order. Outcomes measured included isokinetic knee extension and flexion torque and power, muscular activity (vastus lateralis, vastus medialis, and biceps femoris), and jump performance (jump height and modified reactive strength index [RSImod]). Responses to the stretching conditions were analyzed using a mixed-methods approach. For isokinetic knee extension, dynamic stretching of both agonist and antagonist (DY-AG-ANT) and combined dynamic agonist with static antagonist stretching (DY-AG ST-ANT) produced significant improvements. Dynamic stretching of both agonist and antagonist increased peak torque by 12.72% and average torque by 30.80%, while DY-AG ST-ANT increased peak torque by 15.61% and average torque by 41.06%. Muscular activity also improved significantly; DY-AG ST-ANT increased EMG activity of the vastus lateralis by 29.43% and vastus medialis by 70.75%. Biceps femoris saw a 33.18% increase with DY-AG and a 22.15% increase with ST-AG. Countermovement jump height improved with DY-AG-ANT (12.6%) and static antagonist (ST-ANT) conditions (11.3%) ( p < 0.05). Dynamic stretching of both agonist and antagonist also enhanced average power knee extension by 32.41%, while ST-AG DY-ANT improved it by 31.09% ( p < 0.05). Dynamic stretching, especially when combined with static stretching, optimizes isokinetic strength, muscular activity, and jump height. Coaches should incorporate dynamic stretching, alone or with static antagonist stretching, to maximize performance.