Ex competitive powerlifter weighing in.

The signals that free weights sends to your body, particularly compound multi joint movements like squats and deadlifts are entirely different to isolation exercises (machines). Particularly when it comes to neurological efficiency and hormone response. One's not better than the other, but they produce entirely different strength gains.

For an opinion from a running expert: http://tim.blog/2017/05/07/ryan-flah...omment-1545807

He goes into a lot of detail in the podcast about how he strength trains runners.