The best replacement for flexibility is strength.

The best alternatives to flexibility are rated as following:
★★★★★  strength
★★★★★  mobility
★★★  adaptability
★★★  stretching
★★  range of motion
★★  agility
★  stability
★  stretching exercises
★  flexibility
★  hypermobility
★  rigidity
★  versatility
★  mental rigidity
★  muscle mass
★  structure
★  elasticity
  plasticity
  commitment
  static flexibility
  consistency
  dynamic flexibility

Your alternative for flexibility is not listed? Suggest!
Speaking about flexibility, one probably shouldn't forget about strength.

Other search terms related to flexibility and their ratings are:
★★★★★ strength
You have in mind a companion for flexibility and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of flexibility in all years. Click on graph for more.
flexibility
strength
mobility