Double Olympic and world track champion Mo Farah collapsed after crossing the finish line in the New York half-marathon, having recovered from a fall earlier in the race to finish second to Kenyan Geoffrey Mutai.
Farah fell to the ground shortly after completing the race and was taken away from the finishing area in a wheelchair but later allayed fears for his health.
The Briton, who won the same half-marathon in 2011, endured a tough run after taking a painful fall after five miles.
He recovered to finish in 61 minutes 50 seconds - 18 seconds behind Mutai.
"The conditions today were very, very cold," he said.
"London's going to be different, but I feel good and I felt good to the point I went down."
London up next
Farah said his fall took a lot out of him and affected his ability to see in the latter stages of the race.
"(The) last four miles, I was just pretty much seeing stars... everything was kind of blurred to me," the 30-year-old said.
"When I went down, there was a massive gap, and it was hard to close that gap again."
Mutai's countryman Stephen Sambu finished third to round off a good day for Kenya in New York, with their compatriot Sally Kipyego winning the women's event.
Farah won the 5,000m and 10,000m golds at the 2012 Olympics and 2013 world championships, is preparing to run his first full marathon in London in April.