Washington ? President Bush’s knee pain is the result of wear and tear and injuries over the years, doctors said Thursday in ruling out surgery and giving him the go-ahead to continue careful jogging.

MRIs, or magnetic resonance imaging scans, taken of both knees at Walter Reed Army Medical Center, showed that the 57-year-old president has normal range of motion and strength in his knees, no fluid buildup and stable joints.

Bush consulted with two specialists, Dr. Kevin Murphy, the chief of orthopedic service at Walter Reed, and Dr. Stephen Haas, doctor for the Washington Wizards basketball team.

“Neither surgeon recommends surgery,” according to a medical summary of Bush’s exam issued by the White House.

More specifically, a scan of the right knee showed an old, “incomplete” ligament tear and a softening of the cartilage under his kneecap, a condition often called “runner’s knee.” A tear in the meniscus, which helps cushion the knee, also was noted, but the report called it insignificant and not the cause of current pain.

Evaluation of his left knee showed no change in previously discovered early signs of arthritis.

The doctors recommended exercise to strengthen muscles that help support the knee and stretching. They suggested he continue cross-training, water jogging and exercises to build up his quadriceps.

“And listening to his body,” added White House press secretary Scott McClellan, who recalled that after a calf strain earlier this year, the president acknowledged that he needed to wait longer for injuries to heal before resuming rigorous activity.

The president was at the medical center with first lady Laura Bush to visit soldiers wounded in Iraq and Afghanistan and give a speech to about 200 members of the medical staff. The president also dropped in on Secretary of State Colin Powell, who was released from the hospital Thursday afternoon after prostate cancer surgery on Monday.