Simplify the following text for a Grade 11 native English-speaking person.
Original: There are many different methods of strength training , the most common being the use of gravity or elastic\/hydraulic forces to oppose muscle contraction . See the resistance training article for information about elastic\/hydraulic training , but note that the terms `` strength training '' and `` resistance training '' are often used interchangeably .
Simplified: There are many different methods of strength training , the most common being the weight\/gravity training and the training with the help of resistive equipment .