As good as the NIV is, it is not a pure translation, and the NIV is known to take some liberties. Try looking it up in the King James, which is among the best translations. Then cross reference the Hebrew words of man or able-bodied man with Strong's Concordance. (If you don't have a Strong's, you can find it on line, or I can send you the link.)
Able-Bodied in ancient cultures was not about discriminating against those with physical challenges. It was necessary to have men who could meet certain physical demands of work and service. This is true in certain professions today, such as airline pilots (men or women pilots), for example who need to be able to see. Blind pilots by ancient standards would not be considered able-bodied.
Fire-fighters, police, and soldiers need to be able-bodied in the same sense as the ancients. Normally this has been a male role because men tend to be larger, stronger, have better upper body strength due to muscle and skeleton design, and men normally are able to inject their mean emotions into doing work - high testosterone charge.
In the 21st century, men are evolving into the sensitive ones, sitting around feeling their feelings, while women are learning to fight and evolving stronger sweat glands.