A session on an AlterG machine three days out from Saturday's Elimination Final is only adding to the intrigue surrounding Cale Hooker's availability.

The important forward is attempting to recover sufficiently from bone bruising in his leg to take his place in Essendon's team against Sydney.

Hooker did some brief touch work on Wednesday before chatting with club doctor Bruce Reid and then heading inside the club's state-of-the-art Tullamarine gymnasium.

"The AlterG ... it's sort of a big fancy treadmill where you zip yourself into a pair of wetsuit shorts and you zip yourself into this sort of big bubble," Hooker's teammate James Kelly told the AFL Exchange podcast.

"And you stand on the treadmill, and the treadmill actually weighs you and then you can program a percentage weight you want to run with," Kelly explained. 

"So if you only want to run with 85-90 per cent of your body weight the bubble pumps up a little bit more, lifts you that tiny little bit, takes the pressure off your joints. 

"It takes a little bit of load off your body, but still obviously working your muscles running on a treadmill.

"They're great, you feel like you can run all day on them.

"You can punch out really easy K's, and then get off and not be sore at all.

"The only funny thing is you get off it, and try and run 20 metres, you feel really heavy." 

A decision on Hooker appears set to go down to the wire. 

"Ideally you want everyone to train, but I think they're giving him every chance to play," Kelly said.

"So, taking a bit of load off and getting a bit of faster running on the treadmill, fire up the hammys, keep everything going so then if it gets to the game he's got the best chance to play and play well." 

Fellow Bombers Michael Hurley and Orazio Fantasia both completed Wednesday's solid 90-minute session. 

Hurley has been battling a calf strain, while Fantasia suffered a hamstring tear in round 20.