Baseball
Testing Bats

Skateboarding
Designing Stronger Skateboards

Sports Equipment
These students did a project on the properties of the materials used to make sports equipment. You can scroll down to read about the ideas and see the notes they took as they researched their topic.
http://team8blue.wikispaces.com/Compact+Curriculum+Ch.+2

The Science of Sports Lab Activities
The Chemistry of Sports
Exploratorium Sports Science

Sports Science Projects - From Automobile Racing to Swimming! Check out all the different sports!