Acute effects of different dynamic exercises on hamstring strain risk factors

Area of Science:

• Sports Science
• Biomechanics
• Exercise Physiology

Background:

• Optimizing hamstring muscle performance is crucial for athletic activities.
• Pre-competition warm-up routines aim to enhance muscle function and prevent injuries.
• The specific effects of different dynamic stretching techniques on hamstring performance require further investigation.

Purpose of the Study:

• To investigate the acute effects of dynamic open kinetic chain stretching (DS) and dynamic closed kinetic chain stretching (LEC) combined with jogging on hamstring muscle performance.
• To compare the efficacy of DS and LEC interventions against a jogging-only control group (CON).

Main Methods:

• Thirty-six young men with poor hamstring flexibility were randomly assigned to three groups: DS, LEC, or CON.
• Measurements included hamstring flexibility, muscle stiffness (AUC), joint position sense (JPS), maximal eccentric strength (ECC), and angle of peak torque (APT).
• Assessments were conducted before and immediately after the respective exercise interventions.

Main Results:

• Hamstring flexibility significantly increased in the DS group.
• Muscle stiffness decreased in the DS group, showing lower values compared to the CON group.
• Maximal eccentric strength (ECC) significantly increased in the LEC group, surpassing both CON and DS groups.
• Angle of peak torque (APT) differed significantly across all three groups.
• Joint position sense (JPS) accuracy decreased in both DS and CON groups.

Conclusions:

• Dynamic closed kinetic chain stretching (LEC) appears to be a more effective pre-competition warm-up technique for enhancing hamstring muscle performance, particularly maximal eccentric strength, compared to dynamic open kinetic chain stretching (DS) or jogging alone.
• Dynamic open kinetic chain stretching (DS) effectively improved hamstring flexibility and reduced muscle stiffness.
• Both DS and jogging interventions led to a decrease in joint position sense accuracy.