After visiting a friend today just wondering if anyone else has experience of this?
I have two dogs, different breeds but equal size and build.  My eldest is a 9 year old cavalier.  She has had the highest grade of heart murmour for just over two years which is controlled well with medication.  She still walks off lead for an hour everyday, galloping when she wants to, but spending more of her time than she used to just pottering round having a sniff.  I also have a rather energetic two year old.
At home the Cavalier is without doubt top dog over everything, beds, toys, food.  If the cav is eating my other wont even look at her, nor will she get on the sofa until the cav has decided that she has had enough and jumps down.
On the field however I am seeing behaviour from the youngster neither I nor the cav likes.  If she has found no-one to play with on the field (should add the cav is a lady, and one ought never to induldge in that kind of behaviour, and so has pretty much ignored the younger since I brought her home) she gets fustrated and actively runs into the cav which pushes her over, circles round and does it again.  I'm not sure if this is desperation to engage anyone into a game as she knows the walk is about to end, or a darker reason that she senses the cav doesn't have the ability to put her in her place in a field where she can run away.  I must stress she never does this to anyone elses dog, she knows not to approach a dog unless given the ok, and if she does find a play mate she leaves the cav alone. 
Sorry, turning into a long post!  Anyway, went to see someone with the same rare breed as me, and was very interested that she has exactly the same thing as I do.  Both of hers are the same breed, but eldest is the top dog at home and with everything in the home, but the youngest pushes him over on walks.
Has anyone else dealt with this.  I am currently working to stop this behaviour as its not nice on my Cav.  Just wondering if anyone found anything to stop this, as although I'm seeing progress it is not as fast as I'd like.  I have 6 different walks that the dogs go on to add a bit of variety to life, these cover woods, fields, a river walk and the beach.  So not like shes bored on her walks, always something new and exciting to see.  She point blank refuses to play with toys when on a walk, jumping in a stream is much more fun.  At first she was promptly put on a lead if she did it.  I've got it down from repeatedly pushing the cav over to just once when she will do a perfect recall and sit for two minutes before we continue our walk, but stopping that first push is proving tricky.  As I said she wont even think about doing it if a dog has played with her on the walk.
My friends just ignore the behaviour as none of the dogs (both mine and hers) have ever reacted to the situation.  But my Cav isn't well and its not fair on her.  She tends to know when the youngest is about to do it, and gives me that 'youngsters' look, and then will stand inbetween my legs, or lie down if she is some distance from me.  (You cant be pushed over if you're lying down.)  I should prahaps add the youngsters run ups are generally 1/4 mile long, and she can out run border collies.  This generally gives me enough warning to stand over the cav, but all our lives would be much nicer if this didn't happen!  Any thoughts?

Funnily enough I was discussing this with a friend only last night....and we both have cavaliers.

She has a large pack of them rangeing from a young upstart male through to an old (11) male with many females in between. The discussion got around to the dynamics changing within the pack as the oldest starts to get picked on. Her old boy has started to be sidelined at first and now pushed about and generally jostled and stolen from ...something which never used to happen.

This has started outdoors ( garden mainly) whereas the situation is pretty much as was indoors.

We decided that indoors there were many 'pinch points' ie doorways, corridors and gaps which the younger ones have been taught are conflict areas - where you dont challenge others. Established rules seem to take longer to break down indoors because of close proximity, habit and your closeness to the situation.
Out doors the escape routes are many and poking an oldie and running away seems more achievable and less risky.It does seem to be a the point where we have to step in  protect the more vulnerable aged ones from the up and coming upstarts.
Sadly its the way of the world and 'nature'.....happens to old people too!! Weakness is often used to anothers advantage.

I actually think this is a very normal behaviour.

My mother has a pack of 7 so it is easier to see the behaviour with her pack, her alpha bitch is a very strong alpha she rules the roost no doubt, all the dogs submit to her not that she has ever had to do anything but give subtle body language to hold her status. She just has an air of authority about her.

However, on walks occassionally the alpha male if he is excited and some of the lower ranking dogs will often do the same thing you have described she sometimes has 4 dogs all rushing her at the same time, then they all walk and run together with no further contact.

Perhaps it is a little of testing the water, but it has never impacted on her status and seems to just IMO be normal pack behaviour. I've always seen it as excitement not challenge and this is how dogs show their excitement by having the odd scrum, much like a rugby match. :-)  The fact that the alpha as in your case may be too old for this type of play doesn't seem to register.

I agree, with my two it seems to be over excitement from the youngster as it is often followed by a play bow, I'm only trying to put an end to it as my Cav is so ill.  I have been expecting a few arguements between them as Libby is now reaching maturity and the cav is unsteady on her feet sometimes, so far there have been no signs. 
I have a funny old Cav who really would rather she was a cat!  She doesn't want to interact with any dogs whether she knows them or not.  Shes not fearful, or aggressive, she just pretends as if she cant see them and walks on.  The only time she has interacted with Libby in the last 2 years is when Libby is in season, and the first week we brought her home the cav politely but firmly put her in her place.  This hasn't stopped Libby worshiping her, she constantly presents the Cav with her toys, who doesn't have time for toys and gets annoyed that she then has to walk around them!  (Thankfully the cavs behaviour hasn't stunted Libby's social skills.)  So there is never any play between them unless there is a season.
Looks like this will be slow progress.

> poking an oldie and running away>

'Knock a door run away' springs to mind - Hope it's not only me that's done that as a child.  Do agree about the picking on the vulnerable - it's something I think, most yungsters, of whatever animal species, will try on; and will need to be taught not to.

...and will need to be taught not to...

Thats why I posted.  I've made good progress in correcting the behaviour, but getting rid of that first push is proving tricky.  Wondering if anyone out there has had sucess in stopping it completely.  Short of buying another dog for Libby to have as a full time play mate (which I wont do) I'm running out of ideas of how to stop it completely.

Try anything - games preferably, but water spray is good as an adversive, to stop your youngster well before she gets near your older dog.  I say games because I believe that if you teach her that outside you are the one for fun and games she will change her focus onto you.  indoor games are probably less energetic for yor older dog who probably enjoys them but outside it's too much.  perhaps you could also start to play more inside with your youngster so that her 'playtime' isn't all focussed around your older dog.

I actually train dogs so covered on all basics, but just branching out for advise as I'm stuck! Hence long posts to give full back ground.
When I say my dogs dont interact, I mean my dogs dont interact.  At all.  Ever.  They are pleasent with each other, never even the lowest level of disagreements or nastiness.  The cav plain ignores Libby, and Libby worships the cav but has learnt not to expect anything back from her.
To give background my dogs get an hour off lead everyday over different terrians.  The youngster also gets a full half hour to 40 mins of fetch and games at lunchtime.  They come to work with me so see new sights everyday, group training one night a week and a show every weekend.  Of course there are also smaller games through the day and cuddles.  She is kept entertained!
I dont disagree with your advise at all, I would give it myself, but unfortunately I have tried it.  Any other ideas?
I train using rewards, hence not wanting to go to water sprays but in anycase that wouldn't help with this bitch.  Dancing in a sprinkler/hose pipe is one of her favourite activities, and I fear will make the activity more entertaining!  She is fast, easily out runs fit Border Collies, so reaching my cav before she does on a field isn't always possible.  I'm considering using a loud whistle on her run up to distract her, then doing a recall or other command to make her forget but with just 4-5 seconds to get a response and leave I'm not that hopeful.
I know finding a playmate to walk with would solve it completely, but i just haven't been able to find anyone.  My dogs get walked through rain and snow, most people round here are fair weather walkers!  Please keep thinking!

Thanks for not shouting me down.  Will try thinking some more.  Good luck.

Thanks, all help welcome! Just trying to make the time my cav has left as pleasant as possible.

When I have any 'oldie poking' I keep the oldie on lead until the 'poker' is distracted and goes off to do their own thing.
Getting the younger ones to go off to retrieve then gives enough chance for the oldie to potter off while you conduct the game with the others. Making sure,of course, that the oldie doesn't get bowled over in the game :-)

Going back to days when I trained more and thinking about what you said about the whistle: could you trian your youngster to 'drop' to the whistle.  I haven't done this recently, but have done it with about 3 of my past dogs, and successfully :-).  They were a mix of collie x FCR, GR, collie x, so all working/trainable types, but from what you've sais you have the expertise [which I don't particularly] and commitment, and your little one has the ability. 
Not wanting to 'teach my granny to suck eggs' so to speak, if you could build up the down over time so that she could do it next to you, going away, coming back, where-ever you could stop her in her tracks.  My collie X Flatcoat absolutely loved this, he was ball mad and training mad - he was the one I could do directional control with, not just static, but stopping him and re-directing him for a find [hand/arm signals as well as whistle and voice].  I could also 'drop' him when going for the ball at speed. 
Now for the guilty admission - I couldn't do the same when he ran at people in order to protect me - depends on what's motiviating them doesn't it.  So, it may work for yours, depending on what's the dominant goal for her.

I think I'm going to give the whistle a go.  Unhelpfully I have an unusual type of gundog that was bred to work in complete silence and audio commands tend to bounce off them.  Hand signals however they respond to immediately.  I will try training her with the whistle over the next couple of weeks, probably using it as a distraction and then waving my arms around like a mad woman to give visual distance commands!  If that fails I'll resort to the good old 'whistle has blown get here quick to catch the sausage' routine.
Summers coming so I know I wont have these problems during these months as there will always be a dog somewhere for Libby to play with.  My cav really is just such a lady and doesn't do mud- unless its chasing a rabbit, the look of disgust on her face when shes pushed over in a patch of mud kind of says enough is enough!