Deep conditioning and protein treatments are some of the best methods. Our hair generally loses its elasticity through excess heat, manipulation and even improper color-treatments. Refraining from heat, doing protective styles more often and making sure you’re color-treating your hair properly are also good tips. Here are some blog post articles that might help:

http://www.naturalchica.com/2012/08/understanding-hair-elasticity-by-trichologist-dr-kari-williams/

http://www.curlynikki.com/2011/06/elasticity-and-healthy-natural-hair.html

Hope I’ve helped :)