A few points …
Soccer is very skill based – so physical aspects have never been emphasized as much as in Rugby (to date).
The higher up the levels the less ‘strength’ work generally done and less emphasis on physical advantage – ‘If a player is poor sell him rather than try and improve him’.
To be perfectly honest – even in the most advanced UK clubs you could do any weight training and improve them
The dynamics are also very different – while they may be arguably as strong per body weight etc etc – there is a massive difference in VO2’s
Now we know VO2 is not as important as we used think – but it still is a measure of aerobic ability
Bris makes the most important point though about the Prem and that’s the number of games you have to manage – it’s essentially about keeping guys on the field from week to week.
Off season is literally 6 weeks if you’re an International Player
If you had 5 months to prepare a Premiership team in the UK you’d win every competition in Europe
One point though that is important is that traditionally the coaches were actually more Physio’s – if you look at the structure in soccer the head of most Physical Preparation departments was actually a Physiotherapist – which is a completely different attitude to S&C coaches in Rugby.