Solved

Driver stamina and weight

Hello Aishwarik,

The attribute that gets improved is random.

When your training focus is set to Physical, the game will randomly select either weight or stamina to train. Once an attribute cannot be trained any further, it will automatically be removed from the randomiser. 

i.e, once Stamina reaches 30, only weight will be trained. If both weight and stamina are fully trained, you will need to change your training focus or you'll see no improvements through training. 

I hope this helps. If you have any further questions, please feel free to ask. :)

Hello,

Weight will increase/decrease until the BMI is at a healthy level (which is indicated by the colour of the number changing). 
Once BMI is at a healty level, weight will stop being trained and therefore won't change any further.