So I've not got much idea about this as I've only been practicisng aikido for a couple of months, but...
...there are some basic movements (tori funi, tenkan, can't remember or spell other names) that could be done on my own. I guess if I were going to get good at football (soccer) then I'd go and kick a ball against a wall. It wouldn't teach me how to tackle or to pass, but I'd get a feel for how to kick and it'd improve eye-body coordination. Maybe the same applies to aikido? Doing these movements lets us get your balance right. So maybe it depends on what we class as practice and training?
(Who is the Bear in the Big Blue House?)