Time difference between grass and road ?

Spirogyra

Hi today I was about a minute and a half slower on grass than the road. OK it was muddy in places but I was still surprised at how slow I was. What's others experience been?ðŸ˜႒

glacial_pace71

I too would be curious about this.

I'd generally be about 10-15 secs per mile slower on grass than on the road. (I'd be c.9 min miles for plain vanilla mileage in training, so adjust 10-15 secs as a percentage if calculating your own road:grass difference). However, it depends a lot on time of year, e.g. the Phoenix Park turns very mucky in parts.

Also the type of grassy surface makes a huge difference too, e.g. the presence/absence of tree roots can subconsciously dictate a pace (I've gone head over heels like a dramatic Ronaldo-style dive even when just stubbing on a tree root at 8:30 to 9:00 min pace per mile).

Elevation can be easier to gauge on a road than on grass, which can be a further complicating factor, e.g. you mightn't be comparing like with like.

Here's an example from Saturday, in which I meander around the Phoenix Park, on grass, trail, road, path etc (trying to avoid Frank Duffy 10 miler). The pace varies as much with elevation as with surface but - all things being equal - if you look at comparable segments of grass with road the difference is about 20 secs per mile, albeit on a slow run of c.9:25 pace.

https://connect.garmin.com/modern/activity/1314870263

hillsiderunner

I'm running a lot on grass these days and I think it'd be about 30secs/mile extra on average when you take the run onto the grass. But will be over this for rougher grass and less on a nice firm golf course!

We are working our legs harder so you'd hope it'll pay off in the long run .

robinph

Far too many variables to be able to compare really.

If you are comparing running around a perfectly flat 400m grass track that is well looked after with running around a cinder track or an Olympic standard track then you can compare and say that there is X seconds difference between them.

Otherwise there are far too many differences. Is it pavement with lots of driveways and side roads, or a flat smooth non potholed surface during a race down the middle of a closed road? Is it a flat grass field you are running around, or is it across some open countryside with long grass tree roots and cow pats to avoid?

Spirogyra

In this case 'cross-country' how I much do those these times vary from road ?

robinph

Spirogyra wrote: »

In this case 'cross-country' how I much do those these times vary from road ?

The same course on different weeks could vary massively. Ignore times on XC, it's all about places.

demfad

Spirogyra wrote: »

In this case 'cross-country' how I much do those these times vary from road ?

If you're in a cross country race and want to estimate your road fitness you could google recent results of the runners who finished around you
(change the Search Tools to only search for the last 6 weeks).
Only for a general idea.

If youre running along a tarmac path beside grass try timing the same section on both surfaces at the same effort. Do this for different routes in different conditions.

I've done this on occasions and noticed that the grass running seems to make my tarmac running instantly more efficient (after I step back on tarmac) . Softer surfaces can make you a little lighter on your feet because some inefficiency is punished by 'sinking'. I always meant to try alternating grass reps and tarmac reps just to see..anyway, that's a tangent.

Tombo2001

Not the answer you want - but does it matter?

When you are training, you know by how you feel if you are going hard enough.

Some people run better on grass; others run better on road, others on track. Last year, I was beating a guy consistently in cross country, and he was beating me consistently on road.

Mulberry

A couple of years ago when marathon training I did a lot of easy runs on the grass/trails/paths in Phoenix Park.

I also did a lot on regular roads.

My easy pace on the roads was almost always 9mm, in the Park it was almost always 9.15-9.20. If I sped it up or slowed it down it was pretty much the same. Say 15-20 seconds at around that pace. Never really varied.