Before starting a personal training program with a 'professional' trainer, you might like to give one of the following applications a try. Which app you choose will depend on your overall health and fitness goals, and your personal exercising preferences. The digitizing of information that is occurring rapidly within all sectors of the economy is helping to bring all of this information directly to the end user, allowing them to skip the expensive middle man.
Are you an advocate for HIIT / CrossFit? You may wish to try iWOD (IOS only). iWOD is jam packed full of videos highlighting the correct form and technique for many typical routines found in a cross-fit program like burpies and double-unders. Their timings are also fully customizable, meaning you can create your own workout in minutes that you can set and forget.
If you wish to analyze your individual athletic strengths and weaknesses, and then have a program formulated just for you based on these, then we recommend FLOW Competitive Sports from the Simpliflow team. These guys are a dedicated team of sports scientists and experienced sports coaches, and 'they' will take you through 8x initial tests to determine your strengths and weaknesses. They are tailor a specific program based on these! Again, they have some top-flight HD videos that show you the correct form and technique to use for each exercise, limiting your chance of an injury hampering your progress against your goals.
If you own a windows phone (5% of smartphone users can not be wrong), then you could look at 6-week training from Herm's Software. This application helps to create callisthenic / HIIT type programs, and is geared to progress the user towards their predetermined 6-week goals. Progressive overload is part of the experience, so all the user needs to do is complete the task as described, and they can be sure that they are making progress after each and every workout. There is also regular 'testing' to ensure that the workouts are not too easy or too hard. We also love the ability to visualize this at any point.
Are you a runner looking to get their times down? We can not go past Strava from Strava Inc. This is the most feature packed GPS tracking app that we've seen or used. It will communicate with most wearable devices (HR monitors, smartwatches etc.) and will sync all data with a bank of cloud services so they are visible from any web browser anywhere. There is a cool social feature too in the premium version, which is well worth checking out!