In today’s high-tech world of wearable devices coaches and athletes can track, monitor and analyze just about anything to help improve performance – heart rate, power, pace, HRV, glucose levels and so much more. When looking at improved running performance over time, two closely intertwined metrics I like to monitor with my athletes are ground contact time (GCT) and vertical oscillation (VO). Both metrics are captured by many GPS watches when connected with a chest heart rate monitor, pod or running power meter such as Stryd. Within the Garmin family they are referred to as Running Dynamics. Improvement with either or both metrics will improve running efficiency which ultimately boosts performance. Keep in mind much of this is individual and specific to your personal physiology and physique. We should be careful to avoid chasing the “perfect number” and avoid comparing ourselves to elite athletes, our friends and training partners. Likewise, I always caution my athletes to not be too over analytical when sifting through these and other metrics.
Ground Contact Time (GTC) – the measure of time in milliseconds that our foot is in contact with the ground with each step while running. Most athletes are typically in the 200-300ms range while elite runners will often have values that are sub 200ms reaching down to 175ms. Generally speaking, the faster you run the less amount of time your feet will spend on the ground. For anyone who consistently has values above 300ms there is likely room for improvement. A sub-metric related to GTC is GTC Balance which measures the symmetry between your left and right sides. An acceptable range is 49-51% with a differential greater than 2% often considered to indicate poor symmetry. This metric is important as good symmetry will help reduce risk of injury and improve efficiency.
Vertical Oscillation (VO) – the measure of how much our torso moves up and down or how much “bounce” we have while running. The sweet spot for most athletes is 5-10cm (~2-4’’). The goal with running is to be propelled forward as efficiently as possible while moving both vertically and horizontally. VO reflects how much energy is being spent driving us up and down. Too much bounce or a VO above 10cm often becomes inefficient as we waste energy and does not contribute to effective forward motion. Too little VO, below 5cm, indicates lack of “flight time” or time spent in the air and an increase in GCT. Factors that contribute to having an excessive bounce include not having a slight forward lean and mistiming the take-off phase of your stride. A low VO typically reflects lack of general conditioning/fitness and lack of strength, especially in the glutes. Like many variables, VO will change relative to terrain and pace. Honing your sweet spot is kind of like the porridge in Goldilocks and the Three Bears kid’s fable – it shouldn’t be too hot or too cold, but just right!
How to improve GCT and VO:
Here are some of my go-to plyometric exercises with video links which I recommend mixing in as part of a year-round periodized strength training program:
Run like the wind,
Coach Brad
Coach Brad Seng enjoys working with athletes of all abilities who set a variety of personal goals. He understands difficult training days. Challenging days and subpar workouts are inevitably part of the triathlon landscape, as are the times when you’re feeling great and everything clicks. He believes there are lessons to be learned from experiencing both. Sometimes having to fight for a workout is just what’s needed to achieve an important breakthrough in mental conditioning.
Coach Brad is a USA Triathlon Certified Level II, USA Triathlon Certified Youth & Junior, Training Peaks Level 2 Certified Coach and NESTA Certified Sports Nutritionist (National Exercise and Sports Trainers Association).
