I've hit a proverbial brick wall with my research. I've been researching the Isa rune, and obviously my first stop was the rune poems. However, when trying to look further to see if the Isa rune had other meaning attached to it through kennings or other works but I keep coming across websites, and the like, that claim Isa have meanings that seem contradictory to what the rune poems say, such as Isa being an obstacle or representing tiredness. I was wondering if there was any truth to these ones such as these as no sources were listed?
I mean... I'm not usually a fan of those websites and stuff, but I can't help but note that you have, in this instance, actually run into an obstacle and stagnation in relation to the i-rune.
For me the question is never really "is it true?" but rather "where does it come from?" The former question is outside of my ability to evaluate but the latter I'm much more comfortable with working with.
In this case, that seems to be either Michael Howard or Ralph Blum. They both list it with that "esoteric meaning." Howard came first but the only work of his that I've found is from after Blum, so I don't know who gave it this meaning first. Neither were exactly what you'd call Norse scholars and this probably has more to do with either the demands of their systems or their own personal cultural biases than anything. If Blum started it, it might have something to do with I Ching, though I know very little about that (which I should probably correct, if I'm to write about the history of runic divination). I can't find anything from earlier than 1982 with this interpretation though I still haven't gotten my hands on everything from that highly influential period and it's certainly possible that the idea was already in circulation before those two wrote it down (wouldn't surprise me if Nigel Pennick were involved, but I haven't found evidence of that).
This interpretation doesn't come from the Armanen runes, so at least it has that going for it. They had some weird shit about it being "the true ego," maybe extrapolating from the English pronoun I (this is speculation on my part). Though, they also associated it with Hávamál verse 154 where Óðinn says that he knows a song which he can use to still the winds and ocean. For the Armanen people this was purely numerical -- it's the ninth rune, and this is the ninth of such songs starting in stanza 146 (the so-called ljóðatal) but I could imagine how this could feed back into a reinterpretation of the rune itself being associated with stillness and inactivity.
In my research of rune kennings, I haven't turned up much variety for this rune. It mostly reemphasizes ice as a barrier on top of water (wave's roof, water's blanket, ocean's lock, river's bark, lake's door); less often refers to it on land (mountain's hat, prevention of earth, land's chasuble (a priest's outer vestment)); as something to walk on or which gives access (broad bridge, birds' path, seal-hunting), and as dangerous or untrustworthy (doomed man's misfortune (fár), doomed man's path (far), a big fall. There is at least one that I know of that does (loosely) hint at it as an obstacle: "prevention of herding." A couple interesting ones I've only found rarely include "Ymir's hide/skin" and one I'm having trouble interpreting due to the pre-standardized language but which I think might mean "containment of meltwater."
There are a few Icelandic phrases referring to ice which mostly support the meanings given in the kennings. I'm getting these from Orð að sönnu, a dictionary of expressions and proverbs. Ekki er gagn að góu ísi is probably not so much a proverb as meant strictly literally, it means something like 'it isn't useful to trust ice after Góa (the fifth month of winter).' An opposite but corresponding phrase is sjaldan er mein að miðsvetrarís 'rarely is harm done by midwinter-ice.' Hávamál reminds us not to praise the ice until it's crossed (this is one that apparently entered the common store of proverbs). A foreign saying adapted into Icelandic is sá vakar ís sem þyrstur er, 'that one liquifies ice who is thirsty.'
Colloquially in Iceland the word ís refers to ice cream (so yes, Ísland could be translated 'Ice-cream land'; also Icelanders eat a disproportionately huge amount of ice cream per capita even in the winter which might be related to the ice cream they have there being ridiculously good... yes, you CAN improve on ice cream, the Icecreamlanders have done it. My favorite ice cream is Danish though).
In the sagas ice does sometimes become an obstacle when the ocean freezes over so badly that ships can't dock. There's also a famous fight scene from Njáls saga wherein Skarphéðinn pulls off some intense acrobatic action-movie fighting moves using the ice to rip through his opponents. Myth and legend also refers to a consequential battle on the frozen Lake Vänern. Needless to say, in a place like Iceland a little ice can't always bring about a cessation of activity although it can certainly change the parameters.