Designing workout database

Im designing a web application to track users workouts. i want each user to have
their own set of exersizes that they can add or delete as they wish. Since multiple
exersizes can be done in the same workout, that is what is giving me the issue, on how
to design around that. This is what i have so far. Any ideas or improvements?


user
id
email
pass
salt


exersize
id
name
userid

workout
id
title
date
notes
userid


workoutSet
id
workoutid
exersizeid
weight
rep
volume
max

volume is basically just found by multipling reps by weight, and max
is found by multiplying reps and weight to another formula. should I
bother including these in the db or just calculate them prior to being
displayed.