Comparison between muscle power outputs exerted by concentric and eccentric contractions

Abstract

Although muscle power output has been evaluated from various dynamic muscle contractions, muscle power outputs exerted by concentric and eccentric contractions due to different physiological mechanisms have not been examined thoroughly. This study aimed to reveal characteristics of eccentric power output exerted by elbow flexion, and to examine the relationship between eccentric and concentric outputs. Ten young males performed single power output tasks via concentric contraction with 40%, 50%, and 60% maximal voluntary contraction (MVC), and by eccentric contraction with 130% and 140% MVC. Power output due to concentric and eccentric contractions was measured using a power measurement instrument with a rotary encoder attached to the pulley. The eccentric contraction velocities in both loads were maximal, about 0.5 s, at about a 90°bend of the elbow joint after the onset of contraction. Although eccentric contraction with 140% MVC completed in about 0.5 s (range, 0.22-0.73 s), contractions with 130% MVC completed in about 8 s (range, 1.41-12.08 s) due to moderate contraction velocities. The reliability of the eccentric power parameters was found to be good, as well as that of the concentric power. The average velocity of eccentric contraction with 130% MVC correlated significantly with the peak power of concentric contraction with 60% MVC. In conclusion, eccentric power may be influenced more by maximal strength rather than muscle contraction velocity.

Eccentric Exercise Program Design: A Periodization Model for Rehabilitation Applications

“…Peak force immediately decreases upon transitioning from isometric to concentric muscle actions, and the parabolic curve in muscle power predictably rises as velocity increases, but eventually declines at relatively high velocities (Figure 5 ). This observed physiologic decline in concentric muscle power has been attributed to the time course required for maximal concentric muscle activation and suboptimal actin/myosin cross-bridge mechanics at high velocities (Hutchins et al, 1998 ; Cramer et al, 2002 ; Demura and Yamaji, 2006 ; Power et al, 2015 ). However, in considering the eccentric power-velocity paradox, eccentric muscle actions may bias skeletal muscle toward maximal power generation at high velocities.…”

Rate modulation of human anconeus motor units during high-intensity dynamic elbow extensions

“…To accomplish a similar outcome with concentric contractions requires a load much less than a maximum voluntary contraction (MVC) that can be moved throughout a full joint range of motion repeatedly for sufficient duration to induce muscle fatigue. Peak power (the optimal combination of force ϫ velocity) occurs at about a 40 -50% MVC load (18,37), and at loads much higher velocity becomes substantially compromised and the ability to complete a joint range of motion fails within a few maximal effort contractions. Unlike for sustained high-intensity isometric contractions, dynamic contractions that are repeated necessarily have a return phase during which the agonist muscles are not active and are therefore necessarily intermittent in power generation.…”