To have the potential to become sources of competitive advantage, resources and capabilities must be non-substitutable, valuable,

Rare,costly to imitate

Explanation:

Competitive advantage is the superiority gained and enjoyed by a business entity by providing cheaper services or products to its customers when compared to other business entities whose prices are higher for the same quality, quantity and value. For a business entity to continue to enjoy competitive advantage the resources and capabilities of the business entity must be non-substitutable ( it must not be replaceable),it must be valuable,rare and costly to imitate. The potential to become a business entity with a competitive advantage it must be very difficult to achieve.

i dont know about your physical education course but usually the key is determination and not giving up