07/11/2011 at 11:00 AM EDT
Russell Crowe is getting into shape, 140 characters at a time.
The New Zealand-born Aussie Oscar winner, 47, has been Tweeting
his exercise routine, kicking off his summer of fitness with a bike ride on June 18.
"First ride in quite some time. Sore legs, sore a**, be worse tomorrow and the next day," Tweeted Crowe.
The actor, who gained 63 lbs.
for 2008's Body of Lies
, confessed to struggling with maintaining his physique.
"If i stop exercising my body tries 2 return 2 its heaviest weight," he admitted to a fan
. (Spelling Crowe's.)
During his 105-day training period, Crowe's diet plan includes "taking in roughly 2400 cal/ 2600 cal incl all beverages," and increasingly grueling workouts, one of which had the actor declaring, "i'm toast"
Still, he's keeping a positive outlook – it seems. "There is a long way to go, one layer of tissue paper per day of effort and diet," the star mysteriously Tweeted.
Still, it's not all "body movement with weighted objects"
and "sweaty 4-shirt mornings."
"Yesterday my 5 yr olds birthday," Crowe shared
about his and wife Danielle Spencer's son Tennyson. "Nothing but Lego."