How to combine running and squating within the week so that stress on the knees is reduced?

Question

After more than a month walking at a fast pace everyday, my body seems to be adapting and now I need to walk at a ridiculously forced high speed in order to feel it sort of challenging. So I want to start running.

But I am doing air squats once every three or four days or so. The number of squats has steadily been increasing too, and I plan to restrict them to once a week.

Running might impose some stress on my knees, so I want to run only once a week as well, at least for the first month until I am convinced that everything goes well.

So, my question, which one the following two alternatives is best, in order to minimize the risk of knee injuries?

• Running and squatting on the same day. Good: it allows a whole week for the knees to recover. Bad: the stress on the knees imposed by the two things on the same day might add up and increase the risk of injury.

• Running on, say, monday and squatting on thursday. Good: Both activities don't overlap in the same day, minimizing the amount of stress within the same day. Bad: only two/three recovery days between activities that put stress on the knees.

Answer 1

Squatting shouldn't be putting any stress on your knees that would lead to injury under the following conditions:

• You perform them controlled, and unfatigued
• You mirror a low-bar squat posture even in your air squats
• You only squat so deep as to get the tops of your thighs below parallel
• You don't use an excessively wide stance

This will result in 0 ACL stress, low PCL stress, low tibio-femoral compression if you don't squat very heavy or very low, and low patello-femoral compression with bodyweight.

You should get your form checked, and then squat as much as you want.

Also, rather than continually increasing the number of squats that you're doing, I would suggest increasing the weight that you're moving. That would help keep repetitions low, which is important when avoiding doing squats in a fatigued state.

Answer 2

More than a year has passed since I wrote the question. In the meantime I became a serious runner (basically because a shoulder surgery forced me to either running or staying a couch potato). My experience now is as follows:

1. It is running (and NOT squatting) what puts stress on my knees (Kate was right, I now know). In fact I often have to insert some extra non-running day in my schedule until small pain signals that arise after a running session completely disappear.

2. Strictly correct squats (I mean slow bodyweight squats) seem to be harmless to my knees, and I do them regularly. BUT:

3. The tiniest deviation from perfect form causes a lot of damage, specially near the bottom squat position. Until I learnt to squat properly I was really scared and had to stop all leg activity and wait a couple of days very often.

My strength training days now are just the day before running, and not the opposite. For instance, I do the squats on monday and run on tuesday. There is no problem in running after squatting, but conversely I don't dare squatting after running. I notice nearly always some tiny quantity of damage to the knee joint the day after running, which disappears in ~24 hours. I don't like squatting during that time.