Bollywood superstar Shah Rukh Khan, who turned 44 Monday, spent some "quiet time with family and friends" on his birthday, putting behind a year of ups and downs and looking forward to a strong comeback.

With only one of his films - "Billu" - hitting the screens in 2009, the actor has promised his fans more action in the coming two years.

"I am a workaholic, but in the last year I couldn't do much due to my shoulder problem. My team Kolkata Knight Riders (KKR) didn't do too well and I shot for just one film 'My Name Is Khan'. My injury also pulled me down in terms of my endorsements, but I had time to introspect and spend a quieter time at home with my children," Shah Rukh told reporters at a press conference in Mumbai Monday.

"I feel more energetic and happy now and totally ready for a comeback with many projects in the next two years after this one-year break," he added.

On his birthday, Shah Rukh has chosen to spend "quiet time with his family and friends" instead of partying hard, his spokesperson told IANS over phone from Mumbai.

Shah Rukh was in the capital Sunday to kick off the Airtel Delhi Half Marathon and cheer and egg on the runners. It seemed like he is still recovering from an arthroscopic surgery he underwent earlier this year for a nagging pain in his left shoulder.

The Bollywood superstar chose not to run at the marathon but caused quite a hysteria among the runners and watchers by just being present among them.

He said: "Though I could not run this time because of my shoulder and knee injury, I'll try to be fit and run next year. Running is a spiritual experience."

The past year also brought him disappointment when his cricket team KKR did not perform too well in the Indian Premier League (IPL) tournament.

Shah Rukh Khan was also in the spotlight when he suffered a two-hour detention at the Newark Airport in the US in August, reportedly over his surname.