eccentric strength
Positive Versus Negative Strength - The Friction Theory is Wrong
Decades ago, Nautilus founder Arthur Jones theorized muscular friction was the source of differences observed between positive and negative strength - reducing concentric efficiency while increasing eccentric efficiency. On several occassions Arthur has stated the following,
“Everything in the known universe that has both mass and motion also has friction, and muscles are no exception. Whether it is an automobile, an airplane, a snake or a human muscle, friction acts the same way: inhibits positive function while enhancing negative function, thus reduces your positive strength while increasing your negative strength”.
While significant levels of friction in exercise equipment can certainly have this effect, research has shown muscular friction is practically non-existant. Although the exact mechanism isn’t yet fully understood, current scientific consensus is the differences in positive and negative strength are due to differences in cross-bridge mechanics. Dr. Michael Reedy of the Duke University Cell Biology department provided me with the following explanation, › Continue reading