Emotional Release: Images Versus Dry Body Awareness
Lack of sensitivity can occur due to using meditation techniques. Whenever a technique is used, such as watching breathing at abdomen or nose-tip, body scanning or the two methods proposed in the question, there will be a deliberate, fixed &amp; gross intention operating in the mind to exert the mind. This 'intention'  &amp; 'exertion' is a thought and it is this thought intention that hinders sensitivity. 

To feel the body, breathing &amp; associated feelings &amp; emotions sensitively, the ideal practise is to simply 'let go' of all wanting &amp; all intention. The mind must be quiet however the effort used must be a little as possible. Just sit, but very quietly.