I never used to do cross training until I met my partner Lisa and she introduce me to cross training, now a year later i am stronger, fitter, faster and smashing my PB's most noticeably this year Virgin London Marathon in 2hr 56min 23s at a tender age of nearly half a century.  Her latest blog article on the subject http://www..com/general-blog/does-cross-training-improve-your-running-performance I think most runners can relate to? I certainly can, How about you?

I can't relate. I don't run to race, I run to stay fast in the mountains, and to keep my ticker insanely strong for the lil' misses. She's insatiable, capiche. My cross training if you want to call it that is, climbing, running and swimming. Enough about me though, a sub 3 hour marathon at fiddy is pretty sweet, keep on keepin' on.

Yes.

I hope so. But if not, I'm having fun.

I would love to see some peer reviewed, published studies on this.  I think we all agree that there is a point at which x-training detracts from the specific fitness needed to run competitively, but where is that point?  People who improve race times after adding in x-training may have improved just due to the increase in work and aerobic capacity - would they have seen the same benefits if they just ran more and stayed healthy?

I started to investigate a little, but then I got distracted by this (I fixed some of the grammar):

Eur J Sport Sci. 2016 Jul 28:1-7. [Epub ahead of print]

Do women with smaller breasts perform better in long-distance running?

Brown N¹, Scurr J².

Author information

Abstract

Literature has established that a range of physiological, biomechanical, and training variables influence marathon performance. The influence of anthropometric characteristics has also received attention. However, despite major marathons exceeding 40,000 participants and approximately a third of these runners being female, no data exist on the influence of the breast on running performance. This cross-sectional study aimed to explore the impact of breast mass on marathon finish time. One hundred and sixty-eight of 321 female marathon runners contacted completed an on-line survey focusing on marathon performance during the 2012 London marathon. Participants were categorised as smaller (<500 g, 54%) or larger breasted (>500 g, 46%). Regression analysis identified that 24% of marathon performance variance could be explained by body mass index (BMI), but breast mass improved the model to explain 28% of performance variation. The model determined that for women with 32/34 or 36/38 underband each increase in cup size equates to a performance decrement of 4.6 min or 8.6 min, equivalent to 34.4 min difference between a woman with 36A compared to 36DD breast size. Larger breasted runners had greater BMIs, completed less fewer marathons and had slower marathon finish times (316 ± 48 min) compared to smaller breasted runners (281 ± 51 min). Twenty-five per cent less larger breasted women finished in the fastest quartile. These results suggest that differences in breast mass are an important factor for female athletes and should be considered in future research in this area.

 Participants were categorised as smaller (<500 g, 54%) or larger breasted (>500 g, 46%). 

I've never thought to weigh my breasts.  Looks like another thing to add to the to-do list.

MTA:  Two postal scales?

Haha, not surprised, but are smaller boobs due to lower BMI and body fat% due to higher training load?  I remember a few girls in college with Cs and Ds who legitimate D1 contenders.

Unfortunately not always. I was not blessed by the boob fairy, body fat seems to reside anywhere but there. And I don't run that fast either. 

The correct question is:

" I have ___ hours a week I'm willing to use to train, how can I make the best use of it?"