A two-way motion sensor meter for measuring arm exercise. The meter is mounted on a wrist band adapted to be affixed to a user's wrist. The meter includes numeric display means driven by an electronic or mechanical system. The electronic or mechanical system includes first and second pendulums. The first pendulum is adapted to swing about an axis in a plane substantially parallel to a user's body. The second pendulum is adapted to swing about an axis in a plane substantially perpendicular to a user's body. Each pendulum is adapted to send a signal to the numeric display means each time it is caused to swing by movement of the user's arm upwardly and/or downwardly during exercise. The numeric display means is adapted to add each signal to provide a display of the total number of signals.