For me, progression in a training program is where science meets art. It is always my goal to be providing an evidence-based practice which using the best and most current research available. Inevitably though, in an individual setting there is difficulty when “the rubber hits the road”. What might work in a controlled, clinical trial or in a case study may not work the same way in the real world. Whilst I am a tremendous advocate for the scientific process, I also understand that big portions of data (whilst extremely useful) can miss aspects that an individualized program will deliver on. Let’s consider a segment of a personal training program which requires 3 sets of 12 repetitions of a bench press exercise. The science tells us that if we do 3 sets of 12 repetitions at a weight which our body has not previously adapted to, we will get progression. This will be in the form of neural, muscular, psychological etc. Left to our own devices anyone should be able to apply the stimulus and elicit a positive adaptation from their body. 
However, the art of progression in training is identifying priorities for progression and also breaking through new walls once we have plateaued our adaptation. For example our client on the bench press might have to work on their technique before progressing the weight to avoid injury. They may also need to improve their range of motion and this is generally best done under a light load. The artistic, creative personal trainer is the one who can provide the stepping stones to allow for the adaptation to occur as easily as possible, without injury and with an eye on future progressions. 
Science Meets Art
So by applying the appropriate principles: 
  • listening to the client’s needs and wants, 
  • programming to the individual and not the masses, 
  • screening and guarding against injury, 
  • setting appropriate goals and providing a progressive model; 
the personal trainer is the artist moulding the artwork through a series of stimulus/adaptation cycles. The application of the art is nothing without good scientific theory and the science is nothing without the pragmatism and creativity of the artist.