From studies of pregnant sharks, it emerged that there may be an "optimum size range" for the mothers.

BBC: Shark mums 'invest' in newborns

And finding just the right beat isn't difficult, as a lot of popular music falls within the optimum tempo range and most other musical genres also have music in that range, Dr. Karageorghis says.

WSJ: Optimal Music for the Gym

Its acoustically angled 50mm speakers deliver extended bass with extraordinary dynamic range for optimum audio performance.

ENGADGET: Turtle Beach releasing entry-level Ear Force NLa, N11 stereo headsets for the Wii U faithful