Here's an article on isometrics I thought some would like.
http://zhealtheducation.com/episode-259-neural-drive-any-strength-you-want-90-seconds-at-a-time/?inf_contact_key=bc4e52a1825e5707eb0f78e8f8c7fd92d88a1d4a87dfa4e4152f90c00a8e68fa
Health, Fitness, Non-Apparatus Exercise, Unarmed Self-Defense, Firearms Self Defense