The group have been permitted to train with strict Coronavirus testing and protocols in place as they begin preparation for the upcoming UEFA Youth League competition.
McCallum said an excellent online programme combined with hard work from the players over lockdown has allowed them to get straight to work at the training centre.
Speaking to RangersTV this week, he said: “I think the first thing that had to be dealt with was making sure that all the protocols were in place to ensure that when we did get back it was safe and we were meeting all the necessary guidelines.
“We have got a team of people from the operations team who have made sure that what we do is fitting with what is required, but getting back on the pitch is exciting for the players and the staff.
“We put a lot in place with the online programme to keep them learning but getting back on the pitch has proved to be a relief for a lot of the players and staff to make sure that we keep working and developing that side of their game.
“If I am being honest we actually never noticed that there was anything different with their fitness which is credit to the players and credit to the programme that was put in place.
“We haven't really had to focus on their fitness and have really just focussed on the tactical and technical side of the game because their fitness levels appear to be at a level where we want them to be.”
McCallum said it is now key for the players and staff to make the most of the time on the training pitch while ensuring everything is carried out safely.
He continued: “It is invaluable because any access we can get to the players is great. From our point of view there's a short window between now and hopefully when the UEFA Youth League game takes place, so we are making one or two tactical tweaks to how we want the players to be and this is the time to do it.
“On the pitch you are getting that balance of ensuring they maintain their fitness levels and push them but also ensuring that they learn certain aspects of what we want to look like when we get to the game.
“We have not quite got there yet but in terms of the opposition we will start to drip feed a little bit to ensure that we focus on us but have an understanding of what challenges we might face.
“Before we returned to training we had to go through testing which the club put in place and we will continue with that until there's some sort of normality.
“The players go to the right places at the right times, they wear face masks until such time we are on the pitch, the cleaning of equipment is very stringent and we have little access to the building so every aspect of that is about making sure we are outdoors and we are keeping distances.
“Our staff planning is all done off-site on Zoom calls to ensure we are not spending too long together so it is just about making sure that everybody is safe and keeping people away from as much risk as we possibly can.”
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