The 39 year old – who retired from the game after suffering a spinal injury in 2010 – admitted he always felt “sluggish and heavy” during his playing days, and he thinks the problem is too much emphasis was placed on using heavy weights instead of skills that would have improved his technique on the pitch.

He told Men’s Health magazine: “I’ve added a lot more functionality into my training. I’m a big golfer and I’m bit into my tennis and having that ability to have the strength but be more functional with it just serves a lot more purpose.

“I look back at some of my rugby with a bit of frustration. The training we used to do was all about how heavy you could squat, how heavy you could do a weighted pull-up, how heavy you could do a bench.

“None of it had any relation to playing. I always felt sluggish and heavy.

“I wish I could have applied some of the training I do now.

“Simple things like skipping or the boxing training that I do.

“I think they would have made a huge difference to the quality of my play.”

And Thom - who is engaged to Nicole Scherzinger - has learnt there are more important things in fitness than just “looking big”.

He said: “When I was in my early 20s, I just wanted to look big, you know?

“If I looked big then I thought I felt good but it didn’t really serve a purpose.

“Now that I’m a bit older, I realise that you just feel so much better if you can use your fitness.

“At the end of the day, it’s about feeling as good as you can.

“Doing bog-standard weights isn’t necessarily the way forwards.

“Strength does serve a huge purpose but you definitely need to mix it up and get in some variety.”