Multiarticular isokinetic high-load eccentric training induces large increases in eccentric and concentric strength...

Area of Science:

• Exercise Physiology
• Biomechanics
• Sports Science

Background:

• Eccentric exercise is known to enhance muscle strength and performance.
• Short-term training protocols require investigation for optimal efficacy.
• Isokinetic devices offer controlled resistance for targeted training.

Purpose of the Study:

• To evaluate the impact of short-term eccentric exercise training on concentric and eccentric strength.
• To assess changes in explosive power and jumping performance following eccentric training.
• To determine the effectiveness of a custom-made isokinetic leg press for eccentric overload.

Main Methods:

• Nineteen healthy males were assigned to an eccentric (ECC) or control group (CG).
• The ECC group underwent 8 weeks of training (twice weekly) on a custom isokinetic leg press.
• Training involved progressively increasing eccentric resistance (70-90% of maximal eccentric force).
• Measurements included maximal force, explosiveness, and drop jump performance before and after training.

Main Results:

• The ECC group showed significant increases in drop jump height (13.6%) and maximal power (25.8%).
• Ground contact time during drop jumps decreased by 17.6%, indicating enhanced muscle stiffness.
• Maximal eccentric and concentric leg press force increased by 64.9% and 32.2%, respectively.
• Explosiveness (force in first 300ms) improved by 49.1% (concentric) and 77.1% (eccentric).
• The control group exhibited no significant changes.

Conclusions:

• Short-term eccentric training, even with only 16 sessions, markedly enhances maximal strength, explosiveness, and jumping performance.
• The custom isokinetic leg press facilitates high eccentric loads, leading to substantial gains.
• Eccentric exercise is a potent stimulus for improving athletic capabilities related to force production and power output.