Keep the back rigid and flat, contract the abs while holding the body in a straight line from head to heels. (fitnessandpower.com)
If you have, you probably noticed that markets don't move in straight lines for very long. (learntotradethemarket.com)
Even though aerodynamics wasn't really a thing back then designers realised that by covering the wheels their cars would go faster in a straight line. (wtf1.com)