[Closed] Is social distancing done with in mountain biking?

The first part seems to be the actual definition of mountain biking or group riding?
You sit behind or in front of someone for 5+ minutes…

I agree with this.

As I pointed out, your breathing roughly every second. A couple of litres of air, into your wake, assume your wake is about 1m2 then that’s a dilution factor of 1:2500

Right. But we know the 2m radius thing is the rule, and that takes into account any 'dilution factor' you care to mention.

When you exercise, you breath more often AND more deeply. It's a multiplicative effect. So you multiply respiratory rate and tidal volume together - in medicine this would be called your minute volume. This will increase 25-30 fold during peak exercise compared with rest. So you're shifting 25-30 x more air. In addition to that, by breathing more deeply, you are recruiting alveoli in the depths of your lungs which are not as active at rest. It's certainly plausible that these alveoli have a different concentration of viral particles.

I guess it depends on how you ride in a pair. I agree, if you're alongside 1-2m away it seems low risk intuitively. But on singletrack climbs you could easily be riding directly behind someone. There are other factors too. If you're meeting someone, you increase the likelihood you'll borrow their multitool or have a bounce on their bike etc. Probably some people will lift-share etc.

I, too, think this is probably a low risk activity. But I don't really know, and I'm very uncomfortable with the idea that people can just think they know better than the advice. To quote George Carlin: "Think of how stupid the average person is, and realize half of them are stupider than that.' Plenty of people will do stupid virus-spreading stuff if they're permitted to decide the rules are for bending.

Right. But we know the 2m radius thing is the rule, and that takes into account any ‘dilution factor’ you care to mention..........

I can see your point, I'm just struggling to visualize how riding behind someone is greater exposure than say sitting 2m away facing them in a park. To give an analogy we can all relate to, you know how bad your BO is in the beer garden (2m social distanced) after an all day epic ride? Yet you couldn't smell your mate coming down the last descent (what we're discussing). It's breathing in very diluted breath as you ride along, vs repeatedly breathing the same air they're breathing.

It also kinda hinges on how you think the rules are decided.

Either :
1) The somethingion of a number of risks to get us as close* to normal for most people as possible.

2) A line in the sand that says any activity that means you come within 1.99m of someone, or have a 1 in X thousand chance of ending up in A&E is banned.

It it's more the first one then you could make an argument for banning all sport regardless of low risk in favor of allowing people to see dying relatives and attend funerals (higher risk, but fewer people and arguably more necessary). Because overall the R number would be about the same.

*not necessarily very close

I’m just struggling to visualize how riding behind someone is greater exposure than say sitting 2m away facing them in a park. To give an analogy we can all relate to, you know how bad your BO is in the beer garden (2m social distanced) after an all day epic ride?

I don't mean following someone 20m behind on a descent, I'm talking about sitting on someone's back wheel on a climb. You're riding directly into whatever they've exhaled, and you could be sitting there for 10+ minutes at a time. So while it might be 'very diluted' breath, if you inhale 3L (approximate vital capacity) 30 times each minute for 10 minutes it's a significant exposure.

The 2m distance is based on droplet spread - the vast majority of any respiratory droplets hit the ground (due to gravity) within a 2m radius of you. Respiratory aerosols (NOT thought to be a major route of transmission in Coronavirus) and other molecules (E.g. smells) can travel a lot further than that 'on the breeze'. It's not the same thing. The question is whether the following rider will pass through the leader's 'cloud' (for want of a better word) of exhaled air before the droplets hit the ground. And if they're moving quickly I'm sure it's easily possible.

Again, I'm sure it's a very low risk activity but 1) I don't like the idea of people interpreting the rules however they like and 2) I worry about the 'optics' of riders wholesale ignoring advice because it suits them when others are making gargantuan efforts to stay away from others.

... the transmission risk within a group of mountain bikers out for a ride on Sunday must be pretty small in the first place, no?

When I see groups out mountainbiking, they are often standing around in clusters chatting while regrouping after each stage of their run. I think organising any sort of group activity automatically increases the opportunities for inadvertent transmission, even if people think they are being careful.

I'm sticking to solo and household exercise for the forseeable future. I don't see any point in risking my own health or becoming a conduit for transferring the virus to other people.

The first part seems to be the actual definition of mountain biking or group riding? You sit behind or in front of someone for 5+ minutes… a very moderate 11.8 mph is 5ms-1 or you breath in what someone just breathed/coughed out a second ago if you keep 5m apart… or 2 seconds at 10m apart (etc.) obviously a fair bit of the time most of us are going at least double that speed… and group road riding ???

But you're not in static air - even if there's no wind there must be a shit-ton of turbulence created by someone's body as they ride. You might get a little bit of the same air but it's very very different to being inside a building sitting that close to someone.

This image of the turbulence behind a timetrialist
(image from https://link.springer.com/article/10.1007/s12283-017-0234-1)

That makes me doubt the simple cone shape shown - http://www.bikeirvine.org/news/2020/4/1/riding-in-the-time-of-covid-19
and also, mountain biking is a lot of more active and mobile than group road riding. You're not as close, your not following precisely the same lines, your body isn't in a static position, and our actual riding time tends to be far less.

Still agree, big groups a bad idea both optically and for maintaining distancing.

Study from Germany indicate that it is proximity, duration and indoor confinement that facilitate viral aerosol infection rates and represent high risk. Outdoor exposure risk is very low.

The fluid dynamics study images above is tosh, plausible tosh, but still unscientific and not peer reviewed.

One thing as I understand it from SARS-CoV-2, the actual virus that causes Covid-19 (the condition), is it's not a true airborne virus. In the air it is spread by water droplets and these fall to the ground rapidly. Hence the distance and that's to cover coughs and sneezes. Just being in the airstream of someone in front breathing doesn't mean you're exposed to water droplets containing the virus, not in sufficient quantities at least. Stood next to them chatting with spit and saliva coming out of their mouth for a few minutes and yes the risk is greatly increased.

Outdoors, sunlight, fresh air, can disperse and break up the virus as I understand it. In virus particle form it's quite vulnerable. The problem is once it hooks onto cells on the body.

Combine the outdoors risk with knowing who your riding buddies are and their activities. People you know who have basically been self isolating and solo riding for weeks. Chance of them being infected and actually infectious at the point of a ride is very low. Okay maybe they went to a shop the day before so risk there but still low chance with precautions.

If schools go back I'd be very wary about riding with anyone with kids though. Also those going back into offices. Schools and offices I still believe are the prime spread environments even if not everyone in them shows symptoms. That and airports and planes.

Of course if we could have an on demand test before a ride then we'd be clear to ride no worries. I'd be happy to pay for a test per ride if it wasn't stupid money.

Larry Lamb

Steve, all 4 nations are advised by the same group – SAGE. So again why has NI moved forward with larger group allowance than England. I’d also add that Outdoor markets will be allowed from the 1st June, thats certainly going to be a crowded affair.

You have to remember there are other factors here at play than just the science, like politics.

I agree with all that. The point is really that a political response it doesn't make it safe.
Objectively many other activities are less safe ... some we choose and others not but ultimately what makes an activity safe or not is how we manage it.

The vast majority of the population treat rules and advice as binary. Is group riding allowed... then it must be safe... Is tennis allowed... must be safe... they seem to require blanket statements.

Totally not cycling but the "school semi-official photographer" is doing a series of individual photo's they are going to merge together.
To make a consistent theme they are taking a cardboard box (75cm cubed) around 100+ kids houses over 2-3 days with an assurance "the box will be disinfected between kids".

I'm somewhat puzzled by how that is going to be achieved as it's not stated .... other than a huge energy source with UV B or microwaves how do you disinfect a cardboard box 100x without it getting soggy? Bleach? Soapy water? IPA?

I made my own box, we asked what the size was but of 100 other parents scheduled for the same day I don't think anyone else asked, they just "assume" as it say's "disinfected" (incl. the OH - "if she says its disinfected then we should just trust them and not ask how) ? I also know several of the families are meant to be self isolating due to symptoms... but as this is "in their own home (drive/garden) it's apparently OK"

But you’re not in static air – even if there’s no wind there must be a shit-ton of turbulence created by someone’s body as they ride. You might get a little bit of the same air but it’s very very different to being inside a building sitting that close to someone.

Erm yes.... sitting inside a building the droplets fall to the ground faster than they spread an adequate viral load at 2m and if you are sitting in a room your not then in the same place as the other person 1/2s later.

Turbulence just keeps the droplets in the air... you can do this for yourself with a spray bottle and some light. If you want Febreeze or similar to settle quickly don't wave at it... let it fall of its own accord which takes a second or so after the initial energy and turbulence has worn off.

Putting aside all the speculation about droplets for a moment, my feeling is that larger groups for socially responsible exercising could have been permitted by now - but the Gov't has been somewhat distracted by defending you know who.

The only new announcement I've seen is non-essential shops to re-open, which is great if you own a shop but is clearly an economically led measure and one which obviously seems less "safe" than group bike rides.

So while I'm still sticking to the guidelines, I no longer really resent others using their own initiative.

The only new announcement I’ve seen is non-essential shops to re-open, which is great if you own a shop but is clearly an economically led measure and one which obviously seems less “safe” than group bike rides.

Arguably more essential than hanging out with your mates, though.

Arguably.

But it'd be a pointless argument since it's not one OR the other.