Ask the group to listen inwards and to think about how they feel. Then work round the group, with people describing in a couple of words or sentences how they are feeling, e.g. curious, nervous, tired, excited etc. This allows the facilitator and the group to tune into each other.
Use this prior to the workshop to set them up for the training/challenge and eliminate any negative feelings (as a positive framing tool).
Also use at the end of a workshop to see if the workshop has had an effect on people’s feelings.