WASHINGTON — The economy's spring rebound turned out to be slightly less energetic than the government previously thought. And, the road ahead is likely to be rocky as the country gets pounded by the worst financial crisis in decades.

The Commerce Department reported yesterday that gross domestic product, or GDP, increased at a 2.8 percent annual rate in the April-June period. That wasn't as strong as the 3.3 percent growth estimate made a month ago.

But it did mark a pickup after two terrible quarters. The economy barely grew in the first quarter — advancing at a feeble 0.9 percent pace. In the final quarter of last year, the economy shrank.

Nonetheless, the lower reading for second-quarter GDP surprised many who had been expecting the government to stick with the 3.3 percent growth estimate.

The main reasons behind the downgrade: consumer spending and U.S. exports didn't grow as much during the spring as previously thought. Yet export growth was still very brisk.

GDP measures the value of all goods and services produced within the U.S. and is the best barometer of the country's economic health.

Since the spring, the economy has lost traction.

"The latest tightening of the credit crunch will hit an economy that was already deteriorating sharply," said Nigel Gault, economist at Global Insight.

In the past week alone, the clogging of the nation's credit arteries had become so bad that the Bush administration proposed a $700 billion financial bailout to Congress in a desperate bid to stem the fallout.