TAMPA – The rebuilding of Jason Giambi’s body is complete. Now we will see if the strict workout program can help Giambi resurrect a baseball career.

Giambi flexes his biceps and the ink ripples on his tattoos. His chest looks like a body builder’s again. Legs that turned soft thanks to a 2004 knee operation provide a solid base.

According to Giambi’s leaked BALCO grand-jury testimony, he stopped using performance-enhancing drugs in July 2003. Since then, he hit .218 with 31 homers and 84 RBIs. In that time, he battled an intestinal parasite and a benign tumor on his pituitary gland. And Giambi carried around the guilt of knowing he told the truth to the grand jury but very few other people did about steroid use.

The biggest question in Yankees camp is, can Giambi rebound? He doesn’t have an answer, but he knows it won’t be because his 34-year-old body isn’t ready.

With the help of personal strength and conditioning guru Bobby Alejo, Giambi turned into a Las Vegas gym rat this past winter. Yesterday, Giambi gave The Post his routine that began in the final week of November.

Giambi never shied from the gym in the previous winters, but on the advice of Alejo, they split the workouts in two. The mornings were devoted to agility drills. In the afternoon, Giambi and Alejo returned to the gym to add muscle.

“Mondays we worked on the chest. Tuesday it was hamstrings. Wednesday it was the back. Thursday it was the quadriceps, and Friday it was arms,” Giambi said. “We incorporated everything. Some days we would use machines and some days we would use dumbbells.”

Until the middle of December, about two months before he would be in Tampa for spring training, Giambi doubted his body would rebound.

“I was nervous and asked myself, am I ever going to feel normal?” Giambi said. “When I started working out three weeks after the season ended, I started from scratch.”

Finally, 10 days before Christmas, Giambi began to feel his body responding.

“I started to get the results,” Giambi said. “The next day I wasn’t as sore and the weight started to climb.”

Alejo’s program called for higher repetitions at the start to lay a foundation and to create muscle size. Later in the

winter, Giambi lowered the repetitions and pounded heavier weights. The result is a body everyone agrees looks better than at any time last year.

“Bobby was a big part of it,” Giambi said of Alejo, who isn’t allowed by Major League Baseball to work with Giambi at the Yankees’ facility. “We did some of it on the fly depending on how I felt.”

Because of his health problems a year ago, Giambi was required to make two visits to New York in the offseason to be examined by Yankees doctors. The Yankees weren’t monitoring his Vegas workouts, but they were more aware of what Giambi was doing. And remember, they looked into ways of voiding the remaining $82 million on Giambi’s contract after the grand-jury testimony was leaked.

“We were more on top of him than any other player,” GM Brian Cashman said. “No one is complaining [about his program] because he came to camp in good shape.”

That was the first hurdle, and Giambi cleared it. If Giambi’s mind follows his body, the Yankees’ biggest question will be answered with a positive.

If it doesn’t? Well, Giambi will look good at the beach.

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Gym dandy

Under the supervision of personal trainer Bobby Alejo, Jason Giambi used offseason workouts to rebuild a physique that reportedly at one time was steroids-aided. Here’s a look at Giambi’s program:

MORNING

EVERY DAY: Agility drills

AFTERNOON

MONDAY: Chest

TUESDAY: Hamstrings

WEDNESDAY: Back

THURSDAY: Quadriceps

FRIDAY: Arms

* Workouts included use of machines and dumbbells.

* At the start, higher repetitions were used to build muscle size.

* Later, weight was increased and reps were lowered.