Looking for some help on how I might design a database for scoring.

The database is to hold exercises. Each exercise is recorded in a different way - eg. running is stored as distance and time, weights would be stored as weight and repetitions.

I have the tables as shown below but I've just got the scores (distance, time, weight, reps) stored in 4 available columns in the logs table. I know there must be a better way to do this. Anyone have any ideas?

exercises
----------------------
id
title
description
exercise_type

exercise_types
----------------------
id
title

logs
----------------------
id
time
exercise
distance
time
weight
reps