Can you elaborate this in greater detail "Strain caused by the physical elongation of the fibres occurs whenever a muscle is taken beyond its resting length. Strain is measured by change in length divided by the original (resting) length (L - L\deg /L\deg ). In other words, a stretch occurs whenever a muscle is elongated past its resting length." What does the equation for the measurement of strain mean and why is it measured that way? And could you explain a little better what is means when the change in length is divided by the original (resting) length?