The question as to whether running on grass or trails is easier on one's joints than running on hard surfaces (i.e., roads) has perplexed me. On the one hand, it seems to make some intuitive sense that the softer surface of grass or trails would absorb some of the stress of the pounding. On the other hand, it would also seem to be only a very slight advantage and any advantage might well be offset by the greater stress on those same joints caused by running on a less stable (more uneven) surface.
Well, an Australian study that will published in Medicine & Science In Sports & Exercise and that has been reported in Runner's World's Peak Performance and on PubMed, indicates that there may not be any significant difference in the actual effects of running on grass or roads. Inflammation and chemical indicators of stress were higher after running than before running and were higher after high-intensity workouts than after lower-intensity workouts. However, there were no differences between doing the same workout on grass or on a bitumen (asphalt or tarmac) road surface.
Since road surfaces are much more convenient to me for running it's nice to know that I'm probably not doing any additional damage to my knees and other joints by taking the more convenient route. I do enjoy running on trails because of the change and the scenery.
I'm planning a long (12 mile) run tomorrow morning. If the rain holds off or isn't too bad, I'll do another 4-6 miles on Saturday morning before heading to the airport to fly to South Africa. While in South Africa, I hope to get in at least a few higher altitude (5700') runs.
Run well, y'all,
The message of Easter: He is not here; he has risen just as he said. (Matthew 28:6)