Why have my strength gains slowed down with each workout?

Without a doubt, strength gains come very quickly for most when they first begin an exercise program. You'll notice that while your strength goes up rapidly, you are not getting bigger each workout. The rapid strength increases experienced by beginners are due to an increased coordination between their muscles and the nervous system. After this neuro-muscular adaptation period, whether you get stronger or not depends upon your training style, nutrition, and recovery. Remember how awkward it felt the first time you did a dumbbell chest press? Well, after a few workouts your nervous system learned how to coordinate the actions of your chest, triceps, and shoulders, while simultaneously learning how to have other muscles keep you still and steady. Basically, you already had that strength, you just did not know how to use it for that particular movement. Weight training exercises are complex tasks that require coordination and practice to perform properly. Imagine you wanted to golf. Very few people can pick up a club for the first time and swing properly and effectively. However, with instruction (lessons) or practice, you become better and your perceived leaps in strength gain will slow down.