break a sweat

JリーグのFC東京は今年からJ1に昇格したチームですが，昨年J2で過ごした経験は大変重要だったと，FC東京の石川選手がコメントを残しています。

It may be early days, but Tokyo's current form is a far cry from its last season in the first division. The club began 2010 aiming for a first-ever title, but ended it in the bottom three as a squad packed with internationals confounded assumptions that they were too good to go down.
"At first I didn't think we would be relegated, but it's a slippery slope," said Ishikawa. "You lose one game and then you get nervous and lose another, and when that happens again and again you go down. It was difficult to take, and it was difficult to see the fans go through it."
But the tough times did not end there. Any hopes Tokyo had of breezing through J2 without breaking a sweat were dashed by a 3-0 defeat to JEF United Chiba on the second weekend, and the club's supporters were so concerned by poor early form that they displayed a banner warning the players not to take promotion for granted.
http://www.japantimes.co.jp/text/sj20120331a1.html

第2節のジェフ千葉戦はbreak a sweatもなく、3対0の完敗だったと記事にはありますが，break a sweatは口語で「激しく動く，激しく運動する」という意味です（『オーレックス英和辞典』旺文社）。breakには「（困難な状況）を打開する」，sweatには「汗」の他にaがつくと「不安，つらい労働」という意味があります。「ハードワークをしないと試合に勝つと大変なことは成し遂げられない」というメッセージをこのbreak a sweatから感じることが出来ました。（Sugiuchi）