So you mustered the energy to work out, got dressed, left the house, got to the gym, hopped on a treadmill, walked for a few minutes, hopped off of the treadmill, and froze. What do I do next? What body part should I train? What machine should I use? How many reps should I do? And most importantly, how do I know if my workout is working out for me? To answer those questions and more, you need a little help, be it from a trainer or a guide. Luckily, a trainer can be affordable, pocket-sized, and available anywhere and anytime. Here are some of the best workout apps you need to download now for more efficient training and better tracking of your fitness progress.