Which gym is best for increasing muscle size and strength, and developing a toned physique? Planet Fitness, 24 Hour Fitness, or Crunch?

I agree with SSG Mullen but will also say from what I seen in these gyms that each of these gyms is a different experience. Planet fitness will have food that isnt really motivating, alot of older people go and they don't like noise. 24 hour fitness and Crunch are similiar to eachnother because they usally have more people of all ages in there and wont yell at you if you make too much noise in there

I believe that any of them would fit your needs. The key to achieving your goals is consistancy. Some gyms have trainers on staff who can answer questions and may be able to create a workout plan for you. You may want to hire your own trainer though, there are good ones out there, but it may take some trial and error to find the one that is right for you. Good luck.