I'd like for an idiomatic Japanese reader with some familiarity with aiki, etc., to take a look at the characters for "straining hands" before I'd totally accept that the translation was accurate, though.
Heresy! The skills are beyond language! Signs of their absence or presence may always be read by those who know, without regard to the language in which the signs appear! All who know, know this! Do not question, lest you release the secret techniques of Aiki no In Yo Face and darkness and calamity spread across the land!
Actually, I'd like to see the original too; my guess is that the translation at hand is representative of the third (and most unfortunate) category of mistresses left undiscussed in the famous characterization of translations: neither faithful nor beautiful.
This particular word choice (and some other minor problems in the English text) raises flags for me concerning both the English language ability and the martial arts background of the translator, so I too would be hesitant to put much weight on the translation.