Have a l0ok at Otake-sensei.
He has long been one of the best examples of beautiful, precise swordsmanship as done in Katori Shinto Ryu, one of the oldest styles still in practice today.
Pay extra careful attention to the following:
1) his posture - ramrod-straight back
2) his decisveness - from inaction to full speed in an instant
3) his concentration - you can "feel" the technique start and end by his presence alone
It is also worth mentioning that you never see him "trying to be strong". He lets the technique do his job, and his power comes from his overall body motion, not from the swing of his arms.
Since modern aikido derives a large portion from the movements of the sword, there is much to gain from looking at these masters.
If my aikido could be that precise, it would be invincible.