The 27-year-old was relegated with Newcastle last season and did not play for the north-east club in their Championship campaign.
"I can't tell you a date when I will be at my peak level, but my fitness is becoming better with every game, and I will work at the training ground to be 100 percent as soon as possible," Sissoko told the Evening Standard.
Sissoko, who had looked on the verge of moving to Everton during the transfer window, said he joined the north London club to help them secure the English top flight title.
"I came here to help them so I hope we have a great season and finish top of the league. They played very well all last season," he added.
"What qualities can I bring to this team? My power and my strength. I have a lot of energy. Everyone knows I like to run forward, so maybe this is something I can add."
Tottenham, fifth in the league standings with eights points, host Sunderland on Sunday.
(Reporting by Ian Rodricks in Bengaluru, editing by Pritha Sarkar)
