Originally Posted by Wiggin
Yeah, just like with lawyers, there are some good ones out there!
I am of course, kidding...to a degree. For the people who need the attention and motivation a personal training provides, it's great.
I was really thinking about more concrete things like correcting the trainee's technique so they do not break themselves and perform well.
A person I know was in a gym when someone else there messed up and dropped ~100kg of barbell straight on their face because they had no idea what they were doing. If the aspiring lifter survived, he needed a mostly new face.
Now that was an extreme case of ignorance, a complete newb using relatively heavy weights, but even small weights will easily pull muscles and do real damage when you do some lifts wrong. And not even the stupid kind of wrong. The right technique is not always obvious. Some mistakes can be difficult to notice even if you have been corrected on them before and know you should be watching out for them - until they cause injury. In the long run, you make mistakes of a different scale. I think most people who have gone to the gym for a while have at least one story of personally, repeatedly, doing something seriously counterproductive until they finally somehow learned it's not a good idea. Often injury is the wake-up call.
Not just safety, but performance on many lifts stands to improve greatly with help, whether that help comes in form of a teacher or a book. Olympic lifts in particular are a waste of time and risky unless someone can teach them to you, IMO.
An iTrainer won't coach a weak female trainee to progress from a heavily assisted chinup to three unassisted chinups. It won't estimate whether an overweight elderly male trainee's knees can take a squat 1RM and if not, what should be substituted. Resistance training is repetitive, but it's also highly personal, chaotic, and at times risky. Software can't decide something like that.