You might think that being good at standing on one leg has little to do with your running performance or injury risk, but you may be wrong. While running, you will spend a significant portion of your time during your run, stood on one leg. Ground reaction times vary between individuals and there are many variables that exist that determine the amount of time your foot is on the ground at any one time. The speed you are running, the type of foot strike you employ (rear foot / mid foot / forefoot runner), reactivity of the soft tissues in your legs and your running mechanics can all have an impact on this length of ground contact time. Despite all of that, the fact that you will be balanced on one leg while running is indisputable.
Poor single leg balance may occur because of inadequate rehabilitation after an injury, poor stability of the leg, resulting from inefficient muscle recruitment, or uncontrolled movement patterns and more. All these factors contribute to stability of the leg and a reduced ability in these areas can predispose the body to injury.
You can test your single leg balance easily, simply by standing on one leg and timing the length that you can maintain balance. We like to test this with the opposite knee held at hip height and the eyes closed. The time starts as the eyes are closed. You should aim for a time greater than 16 seconds. We usually stop the test after 30 seconds as this shows that you have a good level of ability. If you struggle to achieve this length of time or notice a difference between your right and left leg balance ability, it is advised to practice balancing on one leg. By improving your balance, you help to improve the stability of that leg that is crucial while you are running.
There is way more you can do than simply stand on one leg to improve your balance. Obviously, running is far more dynamic than that as you land on the leg, transfer and stabilise force / load over the foot and push off your toes to propel yourself forward. Running is hugely dynamic and your training should consider this. You can challenge yourself by balancing on uneven surfaces, use jump / land drills and multi directional drills. Use your imagination to challenge yourself and improve the stability of the leg.