eccentric contraction is to concentric contraction as:
opposite is to same
Eccentric contraction is to concentric contraction as the lengthening of a muscle is to the shortening of a muscle.
To answer this question, you need to understand the concepts of eccentric and concentric contractions.
Eccentric contraction occurs when a muscle lengthens while generating force, such as when you lower a dumbbell during a bicep curl. During eccentric contractions, the muscle fibers are still actively contracting, but are being elongated.
Concentric contraction, on the other hand, occurs when a muscle shortens while generating force, such as when you lift a dumbbell during a bicep curl. During this type of contraction, the muscle fibers are actively contracting and becoming shorter.
The relationship between eccentric and concentric contractions is that they are two opposing phases of a muscle action. Each phase is necessary for proper muscle function and movement.
So, to answer the question, the relationship between eccentric contraction and concentric contraction is that they are two opposite actions of muscle contractions.