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.

2 Answers 2


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.

  • Thanks, +1. I don't need yet to add weight because I squat very slowly, specially the eccentric movement (each squat takes a total amount of ~8 secons). I know that proper form should cause zero stress on the knees, but that still requires a constant conscious effort. I usually notice during squatting that something doesn't go 100% perfect and have to make corrections. Usually it is a small deviation from the perfect feet position that causes discomfort and sometimes cracking noises. Until proper form is 100% natural to me, I must minimize risks because I am causing some knee stress.
    – Mephisto
    Sep 29, 2013 at 16:53
  • Well, it's not zero stress even for perfect squats, so you're not wrong to ask this question. Slight deviations from your ideal shouldn't be causing discomfort, though. Consider adding some hip and IT band mobility work to help get past any discomfort you have (I'm basing that suggestion solely on what's most common, not anything specific about you).
    – user4644
    Sep 29, 2013 at 17:05
  • What do you mean by hip and IT band mobility? Could you post any link to some site with a description of those things or a youtube video perhaps?
    – Mephisto
    Sep 30, 2013 at 2:57
  • Regrding the deviations, I really don't know if calling them "slight" was appropriate. What happens is that one squats causes discomfort and a twisting sensation in the knees, then I carefully look for a better feet position an then the rest of the set goes fine. It is strongly dependent on the feet position, my knees don't tolerate any deviations from strictly perfect form. I guess the margin for variations will be bigger when they are stronger.
    – Mephisto
    Sep 30, 2013 at 3:05
  • 1
    This video (from about 2:14 onwards gives some examples of hip mobility work). Here's another good set. Again, not sure if this is what you need, but a lot of people do. Worst case, it'll just waste your time.
    – user4644
    Sep 30, 2013 at 4:20

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.

  • 1
    Just a completely irrelevant comment: At 40-something yr old you notice the small quantities of damage after exercise, and you notice too how your body takes one or two nights to recover and rebuilt completely. This is curious. At 20-something you can perpetrate all sorts of offences to your body in the gym without noticing anything other than some DOMs. It is so different!
    – Mephisto
    Nov 9, 2014 at 20:35

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