(exercise bike, and stretches),
you could end up damaging and tearing muscles and tendons, which
you do not want.
Same for singing. It is important to do "warm up" exercises to gently loosen up the vocal chords before starting to sing using the full vocal range. Again, damage can be caused to the vocal chords if these are strained.
Pilates was developed in the early 20th century by Joseph Pilates, a physical-culturist from Mönchengladbach, Germany.