Cat has jumping/back leg sitting issue after very short and quick run away

hi... I am new here.  my 15 year old female, who never had a single problem in life or was ill (indoor cat) has unfortunately had a momnent of inattention (our fault) literally 12 hours ago at nite.. whereby I took her outside as we oftne too and put her on a 3-4feet recyle bin.. form which she just kind of chills and observes.. never going down.. but..  unfortunately, a stray cat was passing by and I didn't catch her on time.. long story short: she jumped off the bin, onto sidewalk, then took off like an arror after the cat .. and I do mean like an arrow.. 100m further.. there was a fence.. the other cat went offer she stopped. this is where I cought her.. so there was 0 zero contact with the other cat and the whole adventure lasted about 15 mins before we were all back home. long story short.. upon return home.. she laid down on floor.. normally she jumps on little chair. maybe she was just tired I thought.. but then later on I noticed she's having bit of hard time jumping on her regular chair... or other places she normaly goes for. she still can do it.. but prefers not to.. so I assume some pain.. I wouldn't say in back legs unless I also noticed she does not sit in the cat usual back legs down position..   she walks arond fine.. pee poo too.. even goes up her cat tree its just a bit slower..  but no jumping really and no sitting on back legs.. this has never happened before..  in fact nothing ever happened to her in 15 years health wise.. so I'm just wondering if you can advise whether there is such a thing is strain of leg.. muscle or what not in cats.. from say getting down off that bin then taking after another cat at full speed ... all this for an 15 year old cat who isn't really used to doing this at all... and if looks like strain.. would you say I should give it a few days and let rest before I put her through stress of a cage... a vet... scans.. pills.. or god knows what else...  any thought would be infinitely appreciated. appetite seems all there drinking too.. thank you.

@alkor

Welcome to TCS

Could it be that all 15 years your cat did not have strenuous exercise and suddenly she ran 100m at full speed after so many years and now get legs are sore and numb from that sprint?
Good thing is that she is doing all her business normally.
Guess you have to observe her for a day or two and see if she gets back to normal after a few days of rest.
If symptoms still persist, bring her in to the vet and have a check. She could have somehow injured herself with all that sudden running.

Yes, it is very possible for cats to sprain their legs.  Your kitty might have landed funny when she jumped off the bin and then exacerbated the problem when she took off running.  It is probably nothing to worry about although if it keeps up more than 48 hours, it's worth a vet check.  If you can try to keep her from moving too much, that will help.  

Does she go to the vet on a regular basis?  I'm just thinking at age 15, she really should be checked over, especially her teeth, and have a senior blood panel.  If you've not had that done, you might want to take her in anyway and take care of everything at once.  

BTW:  a big welcome to you and your kitty to TCS!  

thanks for taking the time to reply!

it is quite new to us because like I Said we are used to seeing her in perfect health. therefore the slightest deviation from that triggers reaction.  it may be nothing.  or it may be something.  I hoped by posting here I'd be able to simply find out whether other more exprienced people with cat issues, would suggest it is a situation that may warrant giving mother nature a few days of rest sleep and healing time.

you made very good point that an older cat, who is indoor and lives a peaceful life where not much running is needed.. not that she has not played in her younger days and even to this day will chase indoor balls with utmost enthusiasm, when faced with a stretch of 100m at top speed and adrenaline pummping, could strain a muscle.. maybe even twist it. we initially though jumping off that 4 feet bin onto floor while already in her mind being at the chasing part that came after ,may have caused a twist at landing, but then we realized how could she run 100m top speed if something happened after landing.  adrenaline? maybe.

in either case, I really appreciate the help.  I'll keep observign her. I cannot see any difference in her walking.  but she isn't jumping the usual chairs. thinking of it.. moving round under it.. but not quite jumping.. I'm thinking its the propulsion system in back (the back legs).. plus I've not seen her sit on back legs once since last nite. and she does it each time to eat or drink.  again I saw her try to put down the bum while eating, but seems to run into discomfort when trying to bend back legs (I think only one in paritcular) all the way to sit. so she remains standing.

will keep posted.  thank you!

At her age, she may also have some arthritis in her joints, and the jump from the bin made it worse. Give her some time and then take her to the vet if it hasn't changed. The vet can recommend some meds if arthritis is all it is.

thanks for all your help and kind words of welcome.

we'll keep close eye on things! I am firm believer in the nearly infinite, and infinitely more intelligent than a man made pill, healing powers of mother nature, for all creatures under the sun, but also know sometimes we have no choice.

thank you again

good day to all.