sergio, it's whatever works for each.
I had to start stretching when I realised my hamstrings, already a little tight, were getting worse. I was riding to work, sitting at the desk, riding home and sitting down again, and it was getting worse.
Stretching after cycling won't necessarily prevent muscle soreness (linky
) but it can help prevent the tightness that leads to discomfort, knee pain or even lower back issues. It is also recommended for general flexibility, and as pedalling uses relatively few muscles in a small range of movement I feel I benefit from trying to retain some suppleness. Lots of suggestions online, including these:
I have a 1-page PDF with several stretches recommended by bikefit guru Andy Pruitt, pm me if you want a copy.http://velonews.competitor.com/2010/08/ ... ing_136713
These are specifically for tight hamstrings:http://www.sportsinjuryclinic.net/cyber ... etches.php
This video discusses stretching for your IT band:http://www.youtube.com/watch?v=mlYM3KWwrGY
A general stretching guide PDF by a local sports therapist (I trust him, he knows his onions) can be downloaded from this page: http://www.restoresportsmassage.co.uk/res2.htm