That way, your smaller muscles can rest once you get to the big weight machines.VitalPeak XT Having strong thighs will insure against injuring your knees. Exercising your quadriceps and hamstrings will help prevent injuries to the ligaments in your knees. To protect your knees, you must do exercises for your hamstrings and your quadriceps. Leg curls and extensions are great for this.VitalPeak XT If you're going to be using weights, start small in the beginning. Small muscles fatigue more quickly than large muscles, so using barbells before larger machines makes sense.