Ground contact time (GCT) measures the time the foot spends on the ground during a running stride. The less time you spend on the ground, the more efficient running is. Fast ground contact time increases running speed and makes running more economical.
What is a good ground contact time?
Ground contact time is related to running cadence and vertical movement, as well as where ground contact occurs. An excessively long stride and a lower cadence often increase the ground contact time, these also often increase vertical movement. Vertical movement makes running jumpy, which makes it not energy efficient either.
The general recommendation is that the ground contact time should be less than 300 milliseconds, but for fast runners, the time can be around 175-200 milliseconds. The shorter the time spent on the ground, the greater the benefits.
You can monitor your GCT and vertical movement with various sensors. For example, the foot pod is popular and one of the most accurate sensors for this. Depending on the watch manufacturer, there are several different options available. However, it is good to note that several watches also offer readings of the GCT, without a separate sensor. However, the readings given by the watch alone are not completely reliable, because that calculation is based on the movements of the hand.
A balanced running
In the contact time, it is also good to consider the half differences. The ideal situation of 50/50 balance between the legs happens very rarely. A difference of more than 2% between legs can affect performance. It is easy to think that a small difference between the legs is not harmful. However, it has been found that, for example, every 1% increase in imbalance increases the metabolic cost of running by 4%. In other words, this increases oxygen consumption very quickly, which also increases energy consumption.
The difference can also be a sign of weakness in one leg, which can increase the risk of injury. It is difficult to say the exact limit for the limit of asymmetry. However, it can be assumed that the strain on the other side, even if it is small, will slowly add extra strain to the muscles and joints.
How can you improve your Contact Time?
Faster running increases flight time and cadence, which often also reduces GCT. However, this does not directly mean that all runs must start running hard. Various technique exercises, strength training, and plyometric exercises that train the speed and strength of the legs develop not only step speed but also GCT. Technique plays a big role in this as well, if the body does not have the strength to maintain a good running form and generate power for efficient running, the posture often collapses.
A lot can be achieved with weekly strength training. In strength training, you should also consider movements performed with one leg, such as lunges, in addition to just traditional squats. Various technique exercises before the run during the warm-up, both wake up and prepare the muscles for the exercise and improve the technique. Different terrains also challenge the legs and balance when running. Small things can make running more fun and enjoyable.
Joubert, D. P., Guerra, N. A., Jones, E. J., Knowles, E. G., & Piper, A. D. (2020). Ground contact time imbalances strongly related to impaired running economy. International Journal of Exercise Science, 13(4), 427.