Shoulder Pull is the centripetal force, in Newtons,with the shoulder being a distance `R` (= 0.61 + `r`/100) meters from the racquet mass center. The Shoulder Pull force, measured in units of Newtons (1 Newton = 0.225 lb.) attributable to the racquet alone is derived from the Work formula and the general formula for centripetal force (centrifugal force). See the accompanying remarks. A complete description of all variables used in this derivation follows at the end.

I |
= | moment of inertia (swing weight) of racquet, in kilograms·centimeters² |

b |
= | mass of ball, in kilograms |

d |
= | distance from axis of rotation to impact point, in centimeters |

s |
= | ball velocity, in meters-per-second (positive is away from player) |

r |
= | distance from axis of rotation to mass center, in centimeters |

v |
= | linear velocity of mass center, in meters-per-second |

M |
= | mass of racquet, in kilograms |

c |
= | coefficient of restitution of the racquet/ball system |