Velocity-specific strength recovery after a second bout of eccentric exercise

Area of Science:

• Exercise Physiology
• Muscle Physiology
• Sports Science

Background:

• Eccentric exercise (ECC) can induce muscle damage.
• The repeated bout effect (RBE) describes the protective adaptation following an initial ECC bout.
• The influence of contraction velocity on the RBE is not fully understood.

Purpose of the Study:

• To investigate if the RBE is greater when both ECC bouts use the same versus different contraction velocities.
• To examine the role of velocity specificity in the RBE.

Main Methods:

• Thirty-one participants performed an initial ECC bout of elbow flexors at either fast or slow velocity.
• Three weeks later, participants completed a second ECC bout at the same or a different velocity.
• Muscle damage markers including MVC strength, muscle thickness, DOMS, and EMG were assessed.

Main Results:

• Faster recovery of maximal voluntary isometric contraction (MVC) strength was observed only when the repeated bout velocity matched the initial bout velocity.
• Muscle thickness and delayed onset muscle soreness (DOMS) were reduced after the repeated bout, regardless of velocity.
• Twitch torque increased at 72 hours post-exercise for both velocity conditions.

Conclusions:

• Velocity specificity contributes to the RBE, particularly for strength recovery.
• The findings support the concept of multiple underlying mechanisms contributing to the RBE.
• Matching contraction velocity between ECC bouts enhances protective adaptations.