Handshakes - body language
Firmness of handshake is not the reliable indicator of firmness of character that many believe it to be. Firm handshakes tend to be those of confident people, especially those who have spent some time in business, and who realise that most people in business consider a firm handshake to be a good thing. Handshakes that are uncomfortably firm show a lack of respect or awareness, especially if used in cultures (Eastern especially) where firm handshaking is not normal.
Handshaking evolved from ancient times as an initial gesture of trust, to show that no weapon was being held. Naturally also the handshake offers the most obvious way to connect physically as a way to signal trust or friendship. In more recent times, especially from the 1800s onwards, a handshake became the way to confirm a commercial transaction. Handshaking by women became common practice much later, reflecting the change of social attitudes and the increasing equality of women, for whom a hundred years back such physical contact was considered improper. Women have throughout time generally been subservient to men, hence the very subservient female curtsey gesture (also spelled curtsy), which survives now only in traditional situations such as meeting royalty, or ending a stage performance.
signal part of body possible meaning(s) detailed explanation handshake - palm down

handshake dominance Usually a firm handshake, the 'upper hand' tends to impose and/or create a dominant impression. handshake - palm up handshake submission, accommodating
Usually not a strong handshake, the lower hand has submitted to the upper hand dominance. How all this ultimately translates into the subsequent relationship and outcomes can depend on more significant factors than the handshake. handshake - both hands handshake seeking to convey trustworthiness and honesty, seeking to control Whether genuine or not, this handshake is unduly physical and (often) uncomfortably domineering. handshake - equal and vertical
handshake non-threatening, relaxed Most handshakes are like this, when neither person seeks to control or to yield. pumping handshake handshake enthusiasm A vigorous pumping handshake tends to indicate energy and enthusiasm of the shaker towards the other person, the meeting, situation or project, etc). There is a sense of attempting to transfer energy and enthusiasm, literally, from the vigorous handshaker to the shaken person, hence the behaviour is popular in motivational folk and evangelists, etc. weak handshake handshake various
Avoid the common view that a weak handshake is the sign of a weak or submissive person. It is not. Weak handshakes can be due to various aspects of personality, mood, etc. People who use their hands in their profession, for example, musicians, artists, surgeons, etc., can have quite gentle sensitive handshakes. Strong but passive people can have gentle handshakes. Old people can have weak handshakes. A weak handshake might be due to arthritis. Young people unaccustomed to handshaking can have weak handshakes. It's potentially a very misleading signal. firm handshake handshake outward confidence Avoid the common view that a firm handshake is the sign of a strong solid person. It is not. Firm handshakes are a sign of outward confidence, which could mask deceit or a weak bullying nature, or indicate a strong solid person. Strength of a handshake is not by itself an indicator of positive 'good' mood or personality, and caution is required in reading this signal. It is widely misinterpreted. handshake with arm clasp
handshake seeking control, paternalism When a handshake is accompanied by the left hand clasping the other person's right arm this indicates a wish to control or a feeling of care, which can be due to arrogance. To many this represents an unwanted invasion of personal space, since touching 'permission' is for the handshake only.