In a trial which started in November last year, the Caversham school started at the usual 8.55am and finished at 3pm, but departed from the one-hour lunch break in favour of a 40-minute morning interval and a 35-minute lunch break.
Pupils spend the first 10 minutes of each break eating with their teacher.
Principal Gary Tenbeth said there were several "at risk" pupils at the school who displayed "social issues" in the playground last year.
"They were socially immature children who got bored during breaks and started to display antisocial behaviour.
"The children would get a game of cricket going, but a pupil would come in and disrupt the game and verbal abuse would follow."
Mr Tenbeth said a game had "a life" of about 20 minutes before it got physically and mentally tiresome.
However, a shortened break meant pupils did not have a chance to get restless and there had not been any issues in the playground since the school had made the changes, he said.
"The change in the children has been very dramatic.
"They don't linger around like they used to.
Because their time is limited, they tend to use it productively."
Altjough Mr Tenbeth was delighted with the results, he acknowledged there were drawbacks.
The shortened lunch breaks made it difficult for staff to have meetings and do administrative tasks.
"But school isn't about the teachers - it's about the kids' needs."
