upper body strength
It's a sport that requires great physical strength.
First of all, we must start [by] running [for] thirty minutes per day to improve our physical strength. (First Certificate in English; B2; Greek)
We all have our strengths and weaknesses.
The great strength of this arrangement is its simplicity.
As everything, education in Spain has its strengths and weaknesses. (Certificate in Advanced English; C1; Catalan)
I think she showed great strength of character.
He has a great deal of inner strength.
All in all, being famous takes a lot of courage and strength of personality to be able to face fame and all the risks that come along [with it]. (Certificate in Advanced English; C1; Romanian)
economic strength
Due to the very function of sport, a countr[y']s success in international competition has been asso[c]iated with its general strength and viability and [has] consequently been a matter of national pride. (Certificate of Proficiency in English; C2; German)
The business is going from strength to strength.
To sum up, I believe that if the suggestions outlined above are put into action our magazine will go from strength to strength. (Certificate in Advanced English; C1; Greek)