MPU6050 accelerometer small motions

Hi,
I have recently used MPU 6050 for its gyroscope and it has worked fine.
Now I am trying to use MPU 6050 accelerometer for very small motion and the Z-axis accelerometer worked fine with the gravity and show +g and -g very well but wen tried to find the small motion I can't find out the value and i think it showed not appropriately and i can't find out the acceleration and speed is small motion.
Can you please show me a way to explore the amount of acceleration well for small movements and the good algorithm for this purpose?

many thanks,