WASHINGTON — The economy sprinted ahead at its fastest pace in four years during the summer, although it is expected to limp through the final three months of this year as housing and credit woes weigh on individuals and businesses.

The Commerce Department reported Thursday that the gross domestic product grew at a 4.9 percent pace in the July-to-September period, unchanged from an estimate a month ago. The performance was impressive given that the housing market plunged deeper into despair. Builders slashed spending on housing projects in the third quarter at an annualized rate of 20.5 percent, the most in 16 years.

Economic growth in October through December is expected to have slowed to a pace of just 1.5 percent or less. Some analysts fear that economic activity might even contract slightly. Gross domestic product measures the value of all goods and services produced in the United States.

The big worry is that people will cut back on spending and throw the economy into a recession. Former Federal Reserve Chairman Alan Greenspan and others say the odds of that happening have grown this year. Greenspan recently warned that the economy is "getting close to stall speed."