Definition of "isometrics"

It is theorized that this is due to the increased capillarization which is stimulated much more by isotonics than isometrics.

1972, Clayne R. Jensen, A. Garth Fisher, Scientific basis of athletic conditioning, page 72

Hand and wrist isometrics and isotonics are performed in the sling.

2011, Robert A. Donatelli, Physical Therapy of the Shoulder, page 66