Having some fun lately doing Isometrics, particularly Free-Handed Isometrics (Pitting Muscles Against Each Other) to put on some definition and shed off unwanted fat from certain areas. By far when it comes to safety and developing lean muscle within minutes a day, this is one of the top methods if not the best in fitness.
I've been doing them off an on for practically a decade and they are an ultimate method to train anywhere and anytime. So how does this method shed fat quick or in better terms burn it like Firestorm from Legends Of Tomorrow; well you create the contractions internally and flex a specific muscle or muscle groups and as you contract, you do so as hard as possible for around 7-12 seconds. When you relax the muscle after hard fought flexing, you bring in fresh blood into even the smallest capillaries in your body which in turn brings highly oxygenated blood into the streams and hits the muscle fibers at their highest peak.
The fat shedding is when you hit the muscle hard and bring in fuel for the muscle fibers and as they contract they send shock waves through your system and hence hit the fat in those areas so hard they are practically getting stabbed to death. This is from my experiences with this method, i'm not a physiologist or kinesiologist. This form of contraction and relaxation creates denser muscles which gives the fat a non-fighting chance. When you have denser muscles, you have greater definition and your ability to create testosterone & HGH goes up big time.
This method is a great way to build muscle control and enhance your abilities to flex and relax at will and bring in fresh blood with every Play(Work)out that gives off signals that says "Fat, you're no longer welcome here, get out or learn the hard way." How long can you do this method per day to get great results? It depends on the individual and what they're looking for plus some people burn fat faster than others and the metabolism comes into play in the individual differently. With any means, this is one tough and awesome way to train and you only need maybe 10 minutes or less to get in an awesome Playout. Does this mean they're also good as stand-alone? For some yes due to lack of movement or have had previous injuries and its the best they can do at the time but for the rest, its important to add movement, HIT Playouts, Calisthenics, weights or whatever gives you benefit for moving.
For great Isometrics to build a strong spine and overall body awareness, learn the bridging exercises here...