When I mentioned field implements being used for armed martial arts, I was thinking about the Okinawan family if armed combat. IIRC, everyday instruments of work were adapted to martial use because the Japanese lords of the island had forbidden the use of weapons under pain of death.
Why shouldn't there be the same development in Europe?
As for the argument of there being no tradition in Western culture of the concept of inner strength, well, this is an alternate history site, dammit. Just have some obscure Christian sect or order deviate from the path of strength through bodily mortification and develop something akin to the Qi/Ki path. A gaggle of monks begin to dabble in physical training where the weather is cold and wet for most of the year in order to keep warm - Scotland, Ireland etc.
During a (Viking) raid, the monks discover that those more physically fit and adept at swinging shepherds' stafs, flails and whatnot, or even their hands and feet fare better than the emaciated followers of ascetic doctrines. "Mens sana in corpore sano" springs to mind.
Along the way they discover that strenuous exercise beyond working in the fields and gardens of the monastery actually enhances their mental prowess (a medical fact) and seems to keep them healthy. Prayer routines are adapted for use while going through "weapon dances" (a.k.a. Kata in Japanese martial arts). This becomes equivalent to mantras and/or centering techniques. I am pretty sure there are numerous passages even in the New Testament which would serve this purpose admirably.
A trickle-down effect starts over time as commoners and nobles alike witness the monks' prowess and start to emulate them or even seek tutelage and training. Washed-out secular warriors who join monasteries to find some peace of mind contribute to the ever-growing and evolving arsenal of armed and unarmed monastic combat arts...well you get the picture. As for some Aikido-like form of unarmed combat being most likely to be developed, I concur whole-heartedly.
Another thought springs to mind. A Christian version of the Old Man of the Mountain and his Assassin sect. A somewhat twisted monastic order (of nuns, maybe?


) seeking to proactively annihilate the enemies of Christendom...scary but fascinating.
Just my 2 Euro-Cents' worth
