Even a lightweight suit will effect optimum performance. Just imagine how much less it would be with a 85kg PLSS on his back.
Those posters at the Clavius forum are not objective. Here's some info on them. http://www.davidicke.com/forum/showthread.php?t=125628 Jay Windley who is the webmaster of the Clavius forum knows the moon missions were faked. He tried to obfuscate something that was really clear here. http://forums.randi.org/showpost.php?p=8135606&postcount=7907 http://forums.randi.org/showpost.php?p=8144391&postcount=7990 He made some more remarks here. http://forums.randi.org/showthread.php?t=251326 This is who Jay Windley is. http://www.clavius.org/about.html
Not to mention an astronaut DID jump up on the moon,just not very high,but with the liquid cooling garmet they wore underneath several layers of space suit as well, above that on the A7L/A7LB suits,it's a wonder they could walk,let alone jump