‘Yank’: A New Term in Biophysics

Biologists and biomedical engineers are proposing to define the term “yank” for changes in force over time, something that our muscles and nerves can feel and respond to.

Need for Change

• Expressed mathematically, acceleration is the derivative of speed or velocity with respect to time. The term for the time derivative of acceleration is “jerk” and additional time derivatives after jerk are called “snap”, “crackle” and “pop.”
• The corresponding term for force which is the mass multiplied with acceleration—in physics, has never been defined.

Significance

• Scientists that study sports often use the term “rate of force development”, ....