Leg cramps aren’t usually a cause for celebration, especially for marathon runners.

But Charles Archer, of Niles, was thankful for cramping up during Monday’s Boston Marathon.

Archer said he was on pace to finish the race around the time two bombs went off near the finish line, killing three people and wounding hundreds more.

Leg cramps forced him to slow down around the 22nd mile, so when the first explosion happened, he was 1/2 mile back from the finish line.

“The Lord was really looking out for me,” he said Tuesday afternoon in a Chicago airport.

Archer said he was a couple streets away from Boylston Street — the location of the finish line — when he heard a blast and saw smoke in the air.

“We didn’t know what was going on … then we heard the sirens and the police,” he said.

Emergency responders kept Archer and the other runners on the course for about 45 minutes before allowing them to leave.

Once Archer got to his phone, he sent text messages to his daughters to let them know he was safe. He said he feels lucky.

“It was just emotional, and still is, knowing that innocent bystanders were hurt,” he said.

It was Archer’s fourth Boston Marathon and his 38th marathon overall.

He said he already qualified for next year’s race and plans on returning.

“I am sure it will be emotional next year going back, but I hope to,” he said.

Archer has lived in Niles for more than 20 years. He works at Life Action Ministries in Buchanan.