I saw a physiotherapist today and asked her a few questions. This is some of what she said…
There is less impact on a treadmill. It’s not as hard on your knees.
(I understand some complain of knee pain on treadmills. If she told me this I assume she means in most cases. I won‘t debate this. It‘s simply what she said.)
She said however, if you race on asphalt, it is better to train on asphalt.
(Of course, I’m going to train more on a treadmill since I care less about my race times than the long term impact on my knees. I won‘t debate this either. It‘s my personal choice even if it only makes a 2% difference over 30 years.)
It is better for your knees to run on soft surfaces such as grass.
It’s harder on your ankles to run on a very uneven surface than it is on your knees.
It’s better for your knees to workout the quadriceps and hamstrings (weight training).
Even if you only hold a stretch for 8 seconds, it’s better to stretch before and after running.
(I thought it was only necessary after running.)
She told me I could do a couple of exercises to reduce wear on my knees. One exercise she told me I can do every day is to stand up, fold a pillow and place it between my knees. Then I can push my knees together (aligned with the second toe) and bend my knees forward but without making my knees pass the end of my toes. You’d end up having your head go down perhaps up to 6 inches when you do that. (Just so you can visualize what I mean. Knees bent but not too far.) I was told to hold this for 15 seconds, go up for a couple of seconds then go down again. I forgot to ask how many times.
The other exercise is to place a towel between my knees while doing leg extensions in a gym. And I should put enough pressure on the towel so I end up working a certain muscle in my legs that helps the knees when you run.