Ashes: Ollie Robinson must improve his fitness for Test cricket, says England bowling coach Jon Lewis

England seamer Ollie Robinson must improve on his fitness to keep up with the demands of Test cricket, says bowling coach Jon Lewis.

Robinson, 28, took two early wickets but bowled only eight overs because of a back spasm on day one of the fifth Ashes Test against Australia in Hobart.

Australia, who lead the five-match series 3-0, recovered from 12-3 to end the day on 241-5.

"[His fitness] is something he needs to improve", Lewis said of Robinson.

"He's got a record of playing a lot of games of county cricket but international cricket is of a higher intensity and you play it all year round.

"So he's got to get used to understanding what it takes to be a full-time year-round international cricketer and playing that extra day, five days of Test cricket."

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Opening the bowling, Robinson was threatening with the new ball, finding plenty of movement to dismiss Australia batters David Warner and Steve Smith for ducks.

But England's four-man seam attack was depleted when Robinson went down, as Australia - led by Travis Head's 101 from just 112 deliveries - counter-attacked.

Robinson has taken 37 wickets in eight Tests at an average of 21.16 since making his debut against New Zealand last summer.

Having played in the first three Tests of the Ashes, he missed the fourth match before returning for the final game of the series.

"With these series we play now, with the times we're in, everything is squashed together so there's not a great deal of rest and recuperation between games," Lewis said.

"That's something he's going to have to deal with. Is it a concern? It's one of the things he really needs to work on.

"He's shown over the course of the English summer and this series so far he can put back to back games together but there's definitely areas he needs to work on."

Lewis is hoping Robinson's injury will improve overnight and he will be able to bowl on day two, a reason why he did not leave the field on day one.

"If he's off the field with a back spasm, he wouldn't have been able to bowl if he spent time off the field today," Lewis explains.

"Those things can come and go so we're hoping with treatment overnight he can come back tomorrow and be free enough to bowl."

'Robinson was a handful' - analysis

Ex-England seamer Steve Finn on Test Match Special: "There's no doubt Ollie Robinson was a handful on that wicket with his ability to bowl a fuller length and get the batter forward. Once he was injured, England had to manage their resources the best they could. They will be hoping he wakes up feeling a bit better. "

BBC Cricket correspondent Jonathan Agnew to Test Match Special: "If you've only got four seamers on a pitch like that, you're taking a gamble by picking someone who may not have been fit to play. Presumably he would have been asked how he felt before the game, but he didn't last very long."