I was floored to hear this. This is definitely a training idea that is not popular among recreational cyclists.
Discuss!
I’ll be honest, I went back to running about a year ago. TR rec’d that I start out running 11 to 13 miles a week. About half that totally wrecked me. 
I would think the risk for injury for a pro rider would be extreme!
Two words… “Bone density”
Well, they already have a strength & conditioning coach and program. I’m not sure the incremental bone conditioning of running is material. Although maybe the combination of RE & some higher impact cardio (like running). At least in older adults.
I just don’t think higher bone density is likely to make a rider go faster in the next 18 months. But some injury due to running is for sure gonna make them go slower…
" A combination of RE and weight-bearing aerobic exercise (e.g., running, skipping, jumping, or high-impact aerobics) is recommended as RE training provides muscular loading while weight-bearing aerobic exercise provides additional mechanical loading to the bone above gravity. Concretely, this combination has improved multiple musculoskeletal outcomes including aBMD, muscle mass, and strength, in older women as well as men [76,94,95]. A systematic review and meta-analysis has summarized that the majority of previous studies with combined RE training with high-impact or weight-bearing exercises have shown an improved aBMD in the lumbar spine and femur neck in postmenopausal women [35,96]. In a systemic review investigating the effects of exercise on aBMD in middle-aged and older men, RE alone or in combination with high-impact loading activities maintained or increased aBMD in accordance with postmenopausal women [77]. These findings were consistent with the results from a meta-analysis of randomized controlled trials in older adults [29]. Taken together, RE alone or in combination with other interventions may be ideal to preserve bone loss or even increase BMD in both lumbar spine and femoral neck, not only in postmenopausal women or middle-aged men but also in the older population."
I doubt they are doing any sort of mileage that runs the risk of injury beyond general soreness; it’s probably just a simple cross training activity to sorta mimic riding for sustaining aerobic fitness and helps with muscle balance.
On the other hand…this is the thing that would concern me.
“the average recreational runner, who is steadily training and who participates in a long distance run every now and then, the overall yearly incidence rate for running injuries varies between 37 and 56%.”
But, maybe among pro cyclists this injury rate is much reduced. Especially given their lower-than-average body weight.
I wouldn’t apply the risk of injury numbers from recreational runners to pro cyclists. Pros know how to go very easy and the risk of injury would be quite low - especially with the low mass of pros. I highly doubt they are doing very much mileage anyway.
Imo, it is nothing to do with riding faster. Its reducing the chance of doing a Tao GH.
The risk of a run injury is much less than breaking bones in an inconspicuous tumble of the bike and weeks of the season being written off.
Which is exactly what I mean when I said:
When I say lower-than-average body weight, that means cyclists weigh less than the average runner. So I’m speculating that might reduce their injury risk.
This reminds me of when Froome said he was keto
Sounds like your typical pro tour rider 
I’m just thinking about Nichols:
“A significantly greater percentage of cyclists than nonathletes met criteria for osteopenia or osteoporosis at baseline (84.2% vs 50.0%) and at follow-up (89.5% vs 61.1%)”
A lot of pro cyclists display osteoporosis at a very young age due to extreme dieting and primarily low impact endurance exercise. Not unlike older populations of sedentary people.
@Pbase you are probably on to something there! 
I generally hate running, but I knock out an easy mile on the treadmill as a warm up prior to doing weights. In the spirit of “minimum effective dose”, I figure a little running (and the weights) might be enough to remind my body to maintain some bone density.
Without being able to read the entire paper (I only have access to the abstract) it’s really hard to take anything concrete away from this since there are a lot of potential variables at play
I’ve got close to a 30 year history of competitive running (with some breaks in between) and have my fair share of injuries over the years. But most of that was when I as either (1) trying to ramp mileage or speed up too quickly or (2) pushing pretty high mileage for a really long period of time. Or just freak things like stepping on a pine cone or tripping over some uneven pavement. If you’re smart about how much you run and are doing limited mileage, it shouldn’t be very hard to avoid injury.
I’m not surprised that JV would do some running in the off-season. I know a number of other individual riders (Tom Pidcock and some others) who also do it on their own. A lot of competitive runners will add in biking in their off season. Given the massive amount of hours these pros do it’s probably good for their body to be able to change things up for a short period of time
That’s a good point. Any rider with a cyclocross background is going to be doing some running.
I’d actually noticed a lot of hiking off season.
But I hadn’t noticed running in the off season wasn’t popular. I know I do a bit, and a lot in my strava feed do. Enough that my (cycling) club even had a winter run group!
I found the entire conversation about training techniques to be quite interesting and worth listening to. Jumbo-Visma Head of Performance on Training & FTP Tests | Lanterne Rouge Cycling Podcast - YouTube
Kate Courtney (MTB) has been running occasionally, according to Strava.
I’ve tried slow jogging and settled for walking. Every week I try to join my wife on a couple 60 minute walks. Worst case we do 30 minutes after dinner. Easy low aerobic work for me. Nice to see a rising vo2max effort from my Apple Watch, it parallels (but lower) the estimates from cycling (WKO and Garmin).
Are you absolutely sure they said miles, not metres!?! 
“I’ve made a grave error!”