The advanced running dynamics sensor and the power sensor are very interesting tools because they give you a continuous and objective measure of the effort you sustain while running.
Power value is more accurate than running pace, which can be affected by the surface you run on, the positive or negative slope of the road, and some weather phenomena such as wind. The advantage of using a power sensor is not limited to this. In fact, current devices are capable of generating other very useful data to analyze and learn about all aspects of your running. This feature turns your sensor into a tool for improving not only performance but also running technique. However, these values are also available when you use the sensors for advanced stroke dynamics.
Let’s see what are the most useful data you can get from using sensors.
Running cadence and stride length
Running cadence is the number of steps you take each minute. It is important to keep track of it because it is an index of running efficiency. Your speed is the product of cadence and stride length (the distance traveled). So to increase the pace, you have to either increase the cadence or lengthen the length of each step. However, the latter solution involves more muscle energy expenditure and therefore is not the best way to go. Many numbers are given on cadence intended as the minimum number of steps we should take in each minute. They often take as an example some elite athletes who can reach and exceed 200 steps per minute in certain races. This also happens because of the pace that certain athletes achieve because cadence is also a function of speed.
If you analyze any track among your workouts, you will see that the cadence increases as the speed increases. At the same time, stride length also increases, but this is a more instinctive and natural variable. Before you focus on a specific number (170, 175 or 180) you need to figure out what pace you usually run at and at what cadence. If you run at 6:40 per km, it will not be easy to get to 180 ppm. If, on the other hand, you do repeats under 4 min per km, 185 is definitely an achievable cadence pace. The best thing to do is to figure out what your current average cadence is and work to increase it. One of the things I do to improve cadence is to do specific exercises on the treadmill where the speed remains constant. At intervals of 3 to 4 minutes I have 1-minute stretches inserted in which at the same speed you have to increase the cadence by 5 to 10 units. Doing it on the road would result in an increase in pace and therefore not in your ability to know how to control and increase cadence at the same pace.
Research has repeatedly shown how an increase in frequency is linked to a reduction in the energy cost of your running and a reduced risk of injury. So to increase the pace you’d better start with increasing the frequency and not increasing the length of each step.
Ground contact time
It represents the total time from the first contact of your foot with the ground (whether it is with forefoot or heel depending on your level and style) to the moment it comes off the ground. This is also interesting as a measure of the efficiency of your technique. A very short time is an indication of speed and efficiency. A very high value, on the other hand, denotes a long stance time related to a hammer-foot position and thus a very long “roll” or excessive knee flexion. When the leg bends a lot you have to “endure” a longer muscle contraction and thus a greater energy expenditure.
Horizontal and vertical oscillation
The horizontal swing is the part of movement you are most interested in when you run because it is the part that allows you to move forward in space. Ideally you should put all your energy into horizontal movement and waste as little of it as possible on lateral and vertical movement. Vertical sway, on the other hand, is the upward movement of your center of gravity that you achieve with each push off the ground. Vertical swing values vary between 3 and 15 cm, depending on the efficiency of the stroke.
There is no ideal value for everyone, but you certainly need to monitor this value to be sure that your energy is being used more in advancing than in pushing up. Those who tend to hop in running typically have high values of vertical sway. The added value of a power meter is that it measures the two components of horizontal and vertical force so that it is evident how your energy is used in each step.
Leg Spring Stiffness (LSS)
This is a very technical parameter. In simple terms it expresses the value of the elastic capacity of your stroke. In the stance phase your legs function about like a spring that compresses, storing energy, and then relaxes. Higher LSS values correlate with higher stroke efficiency. If you want to compare this parameter with other runners, you need to divide the value calculated by the device by the athlete’s weight.
All of these values are interesting because they allow you to assess the efficiency of your running throughout the duration of a training session or race. You will see that very often the indicators tend to get worse as you accumulate miles. This can serve you to increase your concentration to make sure that when your energy starts to run low, you are able to keep a high efficiency so that you do not reduce your pace too much. If, on the other hand, you add up worse running technique (too long strides, high swing, etc.) to the onset of fatigue you will experience an even greater slowdown.
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