They could make a matrial that wolnt rust, and that will not wear down/ break
The difference is that cardio focuses mainly on your cardiovascular system which is vital in activities such as running, swimming etc. Strength training is mainly based on well, strength. How much weight can be lifted. so the difference really speaks for itself. A runner will mostly do cardio whereas a football player will mainly focus on strength. Both can be used simaltaneously in a work out.
