Rest is also important .
It 's how we make strides of improvement , but the easy runs also allow your body to be conditioned to more back - to - back running at a threshold that is acceptable and does n't put too much strain on the body .
Rest is also important and it 's how we make strides of improvement , but the easy runs also allow your body to be conditioned to more back - to - back running at a threshold that is acceptable and does n't put too much strain on the body .