Effect of Weekly Training Frequency With the Nordic Hamstring Exercise on Muscle-Strain Risk Factors in Football...

Area of Science:

• Sports Science
• Biomechanics
• Exercise Physiology

Background:

• Nordic hamstring exercises are crucial for improving hamstring strength and reducing injury risk in athletes.
• Determining optimal training frequency is essential for maximizing benefits in high-level football players.

Purpose of the Study:

• To compare the effects of performing Nordic hamstring exercises once versus twice weekly on hamstring eccentric strength and muscle-strain risk factors in elite football players.

Main Methods:

• A randomized trial involving 32 football players aged 18-23 years over 8 weeks.
• Two groups: once-weekly (n=15) and twice-weekly (n=17) Nordic hamstring exercise programs.
• Assessed knee-flexor/extensor peak torques and biceps femoris long-head muscle architecture using isokinetic dynamometry and ultrasonography pre- and post-training.

Main Results:

• The twice-weekly group showed significantly higher hamstring concentric peak torque post-training.
• Trends indicated greater hamstring eccentric peak torque and improved hamstring-to-quadriceps ratios in the twice-weekly group.
• No significant differences were observed in muscle thickness, pennation angle, fascicle length, or quadriceps concentric peak torque between groups.

Conclusions:

• Twice-weekly Nordic hamstring exercise is more effective for strengthening hamstrings in high-level football players compared to once-weekly.
• Both training frequencies induced similar changes in hamstring muscle architecture.
• Training volume (frequency) appears to be a key factor for enhancing hamstring strength.