Honda rider Marquez suffered a partial shoulder dislocation in a crash at last year’s Malaysian Grand Prix - which he aggravated further in a fall during the Jerez test in November - and underwent surgery over the winter.
This left him below full physical fitness for the Sepang test, with Marquez admitting after the first day of running that his condition was worse than he expected.
With just three more days of testing left before racing gets underway early next month in Qatar, Marquez admits areas of the new Honda “have not convinced me”, and is more concerned about his bike being in a competitive state than his body.
"About physical condition of course I would like to be better, but I saw already these three days that I was not like I expect, but I was able to be fast," said Marquez. "And even like this I was able to have a good pace, especially today.
"But I'm more worried about the technical side. We need to keep working, because the new things we try, is not clear but some of them were a little bit better, but still we need to be pushing because Yamaha is like always - the answer about technical side is the opponents.
"The opponents improved a lot, means that you need to keep working. Looks like Suzuki and Yamaha, they improved a lot."
More Sepang test reaction:
Asked if he felt he could challenge for victory if the first race of the season was held immediately after testing, the Spaniard replied: "It's difficult to say.
"With rubber on the track, everybody is fast. Everybody is riding in [1m]59s, the pace. I mean, [Alex] Rins did a really good job, [Maverick] Vinales too, on the race pace.
"Rins and Vinales are the two fastest ones. Then, I don't know, but I don't feel very very far on 10 laps. Then of course now I'm not ready to finish that 20 laps [race distance]."
On Saturday LCR Honda rider Cal Crutchlow admitted the 2020-spec RC213V seemed a little worse than last year’s bike in turning.
Marquez tried several things on Sunday to improve his feeling with the front end, but admits his physical condition was not good enough to offer sufficient feedback.
He finished the test 13th-fastest overall, athough just 0.415 seconds off the pace set by Fabio Quartararo in a tightly bunched field, and ended Sunday “with a good feeling” having ridden a “very good” rhythm – albeit over short runs.
Marquez crashed for a second time during the test on Sunday, after sliding off at the last corner late in the session. He conceded that he had “reached the limit” with his body by that point.
“At noon [on Sunday] I was broken,” Marquez said. “In the afternoon I went out again, but suffered a fall because I already lacked energy.
“I have reached the limit with my body, because in the morning I forced [it] a little more. The position of the body [on the bike] is still not what I would like.”