Has anyone ever heard of really strange improvement patterns?
For example lets take runner A and runner B, they both start running with a 25 min 5k level of fitness and do identical training (adjusted for their fitness). Runner A rockets down to a 19 min 5k in 3 months while runner A is hovering around 21 mins. Could runner B still catch up with and pass runner A doing the exact same routine?
Before you think you're clever by pointing it out I am so obviously runner B.