From Ken Hart
I recently read a checklist of things to bring and do before a race, and one suggestion was to apply embrocation to exposed legs. What is this and when is it used?
Embrocation is a European that means “lotion”, however, in our context, it better translates as "Linament".
Massage and linaments are highly debated topics, with both pros and cons to their benefits. Here are some highlight of what may become a very long thread. From the context you described, they probably are talking about spring and fall racing, when you do not want to wear tights, but still want your legs to be warm.
Most linaments are irritants to the skin, with ingredients that make the skin "feel hot". Some examples are "Icy-hot", "Ben-gay", and "Musclor". There is some discussion as to whether embrocations really work.
The people AGAINST linaments tend to state that the effect is false, since the active ingredients are actually irritating the skin, which causes a false sense of heat. The people FOR embrocation tend to argue several points:
1) Embrocation is put on with an active or brisk massage. so there is a benefit to the legs from the massage.
2) The irritation to the skin from the active ingredients brings blood to the skin, causing the skin to turn a brighter color of red. (this is from the irritant (usually) and not from the cold. Advocates believe that this increased blood flow to the legs also helps the muscles, and does not go to only the skin.
3) Embrocations are oil based products. As they are massaged in, they leavebehind an oily coating. This coating acts as an extra layer of fat (like blubber on a seal), adding warmth, and repelling water.
Embrocations and massage tend to go hand in hand. Embrocations are normally used by a team's masseur/masseuse. A masseur/masseuse may carry dozens of oils (read linaments / embrocations) of vaying heat and oily-ness.
The colder the event the hotter the linament (to a point),
The colder the event, the thicker the oil, becoming more vaseline like
The wetter the event, the thicker the oil
I hope this helps