Is this why I cramped?

I’ve been training almost exclusively indoors for the last year, and just raced last week. I felt fine during the race but after 90min both of my hamstrings cramped at the same time, and I had to stop for almost 5 minutes to get them to relax. I finished the race solo, but couldn’t push it much after the cramping as my hamstrings felt like they were getting ready to lock up again.

I think I cramped due to a bike fit issue, but want to get some advice in case I need to think about this differently. My FTP is 275, which puts me at about 4 w/kg, and my NP was about 225 after 90min when I cramped, so I don’t think it’s a fitness issue. I preloaded with salt the night before and prior to the race, and had two bottles of electrolyte mix I was drinking, so I don’t think it’s nutrition. The saddle on my race bike was a full inch rearward compared to the saddle on my trainer, so I think that resulted in me recruiting more hamstrings, which overloaded that muscle group causing the cramps. My hamstrings are also sore 2 days after the race (the DOMS kind of soreness) which makes me think I used my hamstrings much more during the race than on the trainer. I need to get a different seatpost on my race bike to adjust the saddle more forward, so I plan to do that which I’m hoping resolves the hamstring cramping issue. Does it seem logical the bike fit led to the cramping in my case?

I don’t think there can be a conclusive determination in most cases. But with the info provided, I would not be surprised if the difference in fit was a contributing factor.

That 1" [25mm] difference is rather large and could very well impact your muscular loading. Even with equal efforts on both setups, you are likely asking different things from your legs in each one. Add to that the tendency to ride with a lower upper body when racing than in training, and the extra tension on the hamstrings is only made worse. Then there is the potential for different saddle height, seated position, back angle and such with a large saddle position disparity.

As the saying goes, “Train how you plan to race” and in this case, that means bike fit/body position. I would make every effort to address this difference as quickly as possible. Match the setups and you will potentially rule out one more different variable between training and racing.


Saddle setback is not a fixed value and is a balance between muscle utilization, weight balance, aero etc. If your race bike position is dialed then don’t change that unless you are addressing a specific fit issue. Move your saddle back on the trainer to match your race position.