Training for a marathon is a huge commitment - and with so long out running, the best kit is essential. Make sure you have enough sports bras - as for each new pair of running shoes, you really need 3 new sports bras! And if they start to chafe it may be a sign they need replacing.
The best sports bras for marathon training are those that are comfortable on the longest runs, offer great support and don't chafe. At both Brighton and London Marathon Expos this year we sold more of the Shock Absorber RUN
bras than any other sports bra. This is because it is designed for runners. There are no seams inside. The band is seam free. It offers excellent support (backed up through research). And the shoulder straps do not slide. Do make sure you have the correct size as the cups should sit smoothly across the bust and you should only be able to get a finger in each side.
For those too busty for the Shock Absorber RUN bra, we suggest looking at the Enell
or the new Lynx sports bra
which both offer excellent support