The 5th edition of the Fitness Professionals Handbook authored by Edward T. Howley and B. Franks define strength as “the maximal force that a muscle or muscle group can generate at a specified velocity.”
Resistance training accord to the above-mentioned authors is a “method of conditioning designed to increase a person’s ability to exert or resist force.”
That being said, there is a difference between resistance training and strength training. The training adaptation one gets from “strength training” is very different from the training adaptation I would get if I am training for hypertrophy.
Its the difference between an Olympic power lifter (who trains for strength and and someone doing biceps curls with a five pound weight. The load makes a big difference. One is maximal the other is not.
Hope this helps.