Yoga most directly improves the health-related fitness component of flexibility.

Main component improved

In standard health-related fitness (cardiorespiratory endurance, muscular strength, muscular endurance, flexibility, body composition), yoga is most strongly linked with increased flexibility through its many stretching- focused poses. Research on yoga programs repeatedly reports significant gains in joint range of motion and functional flexibility, especially in older adults and people with limited mobility.

Other components yoga can help

While flexibility is the best answer for “most likely improve,” yoga can also contribute to:

  • Muscular endurance, because holding poses (like planks, warriors, and balances) challenges core and postural muscles over time.
  • Balance and overall functional fitness, which are often grouped with flexibility and mobility in health-related fitness discussions.
  • Cardiorespiratory endurance to a lesser extent, particularly in more vigorous styles such as vinyasa or power yoga, though this effect is usually smaller than for traditional aerobic exercise.

So, if this is a test-style question asking for one health-related component, the best choice is flexibility.