Mental toughness is what many average gym-goers lack. You get tired, so you stop. This results in no physical change for that period of time. Your perceived limitations inhibit you from making progress mentally and physically. The body can always do more. It WILL follow the mind. If you believe you can do more, it will happen. Most people do not actually know what their limits are, as they have never pushed to get there. The pain becomes too unbearable or too uncomfortable. I like to tell people, “get comfortable being uncomfortable”. You must rely on your mind to get you through the suffering, not your quads.
The definition of Insanity is “doing the same thing over and over again and expecting different results”. Are YOU insane? 🙂