The relationship between eccentric hamstring strength and eccentric absorption during the landing phase of vertical...

This study aimed to examine the relationship between eccentric hamstring strength and biomechanical energy absorption parameters during the landing phase of a vertical jump, and the impact of a pre-season preparation period on these variables in professional soccer players.

Thirty-one professional male soccer players (n=31, age: 24.81±5.23 years) participated in the study. Eccentric hamstring strength was measured using the NordBord system, and countermovement jump (CMJ) landing kinetics were assessed via ForceDecks dual force plates before and after the pre-season camp. The landing phase was analyzed through Peak Landing Force, Landing Impulse, and Landing Rate of Force Development (RFD).

After the preparation period, a significant decrease in Peak Landing Force (5429.89±1865.7N vs. 4939.13±1449.8N; p=0.012) and a significant increase in Landing Impulse (98.2±18.19 Ns vs. 106.54±24.67 Ns; p=0.029) were observed. Furthermore, a statistically significant reduction of 11.6% was found in Landing RFD (p=0.047). A statistically significant increase of 7.4% was observed in normalized Nordic hamstring strength (p=0.021).

The pre-season training period enabled soccer players to develop a "softer" and more controlled landing strategy by enhancing the eccentric braking capacity of the hamstrings. The reduction in impact forces and the increase in impulse indicate more effective absorption of loads on the knee joint. Integrating eccentric hamstring exercises and landing mechanics drills into training programs is recommended to reduce injury risk.