Influence of Pushing Versus Holding Isometric Exercises at Different Joint Angles on Hamstring-Quadriceps Strength Ratio and Functional Performance: A Time-Under-Tension Approach to Injury Risk Reduction

Abstract Background: The hamstring-to-quadriceps (H:Q) strength ratio is a critical determinant of knee stability, functional performance, and injury prevention. Optimizing this ratio is essential for reducing injury risk, particularly among athletes and physically active individuals. Isometric training, characterized by pushing and holding exercises, is commonly used to enhance strength. However, the comparative effects of these two methods at different joint angles, particularly within the framework of time under tension (TUT), remain underexplored. Objective: To compare the effects of pushing versus holding isometric exercises at varying knee joint angles on H:Q strength ratio, functional performance, time under tension (TUT), and perceived exertion among recreational athletes. Methods: Thirty participants were randomly allocated into two groups—pushing or holding isometrics—and trained for six weeks using a time-under-tension protocol. Pre- and post intervention assessments included the H:Q ratio (via hand-held dynamometry), Single-Leg Hop Test, Star Excursion Balance Test (SEBT), TUT, and Rate of Perceived Exertion (RPE). Results: Both groups demonstrated significant improvements in H:Q ratio, hop performance, and SEBT scores (p < 0.05). The pushing group showed greater gains in H:Q ratio and hop distance, while the holding group exhibited longer TUT and enhanced balance control. RPE scores were higher in the pushing group, indicating greater exertion demands. Conclusion: Both pushing and holding isometric protocols effectively enhanced lower limb strength and function. Pushing isometrics were more effective for improving the H:Q ratio and explosive performance, whereas holding isometrics better enhanced dynamic balance and muscular endurance. Incorporating joint angle–specific isometric training may serve as a strategic tool for tailored rehabilitation and injury prevention.