A shock-absorbing hammer may reduce arm muscle strain and consequently reduce the risk of tennis elbow for users.

An industrial engineering team from the University of Wisconsin-Madison reached this conclusion after ergonomic testing.

Graduate student Oguz Akkas pounds nails with an IsoCore hammer.The hammer’s manufacturer, Fiskars, asked the Wisconsin team to evaluate the design, which has a sheath of vibration-dampening material. Fiskars designers speculated that holding onto a shaking object causes users to grip the object tighter, resulting in muscle strain.

Fiskars engineers discovered that the relatively low amounts of vibration in different kinds of hammers would not necessarily induce tighter grips. They enlisted the help of the Wisconsin engineers to figure out whether the shock-absorbing hammer reduced arm strain in its users.

Rob Radwin, team lead, hypothesized that the abrupt stop when a hammer’s head hits a nail is the real culprit behind muscle injury. To test this, he and his team recruited volunteers to drive 20 nails in quick succession.

Test subjects were filmed, and muscle response was measured by recording electrical activity in the hammering arm. Subjects’ arms also underwent MRI examination prior to and after the test.

Results demonstrated that the new hammer design delivered the most kinetic energy to a nail on each swing. Subjects who wielded this hammer also showed less evidence of muscle strain and no increase in grip tightness.