Ankle Flexion metrics and visualization

Learn about ankle angle and flexion metrics in Velogic Studio, including the new 8th marker capabilities and advanced ankling visualization

Historical: Ankle Angle metrics

Historically, Velogic Studio used 7 markers: wrist, elbow, shoulder, hip, knee, ankle, and toe. From those 7 markers, a range of metrics were calculated; for the foot, this was mainly "Ankle Angle" which is a simple measure:

Ankle angle measurement diagram showing simple angle calculation between ankle, toe markers and vertical reference

From this measure, across a capture period, Velogic Studio calculated 2 metrics:

Historical ankle angle metrics showing average and range measurements in Motion Metriqs panel

1. Ankle Angle Avg is the average ankle angle across the whole pedal stroke

2. Ankle Angle Rng is the range of ankle angles (Max - Min)

These are good, simple metrics, and can be used to see how ankle movement changes during a fit. However, these metrics suffer from one major problem: the angle calculated is very dependent on the placement of the toe marker. If placed further forward on the foot, the angle angle will be measured as smaller; further back will give a larger number.

New in v4: Ankle Flexion metrics

With the release of Velogic Studio v4 in 2024, we added the option of using an 8th marker on the rider's heel. This allows a more detailed analysis of ankling.

8th marker placement on rider's heel for enhanced ankle flexion analysis capabilities

If you choose to use the 8th marker, you'll see new ankling metrics in the Motion Metriqs area on the right-hand side of step 2:

New ankle flexion metrics showing minimum and maximum values with 8th marker data

1. Ankle Flexion Min is the lowest observed ankle flexion over the capture period

2. Ankle Flexion Max is the highest observed ankle flexion over the capture period

The older "Ankle Angle" metrics are still available too. If you wish to hide those, see Customising display of MOTION METRIQs.

Advanced Ankling Visualization

If you Lock in a single capture for review (or Compare 2 captures), and then click on either the Ankle Flexion Min or Ankle Flexion Max metrics (see above), Velogic Studio will display an advanced visualization of ankling metrics.

Advanced ankling visualization showing crank angle scrubber with plantarflexion and dorsiflexion indicators

1. Crank angle scrubber is like a normal video playback scrubber (where you can drag the playing head forwards and backwards to "scrub" through the video. The major difference here is that the horizontal axis doesn't represent time in a video; it represents degrees of crank angle in the pedal stroke.

2. Current crank angle is shown on the outside of the circle

3. Ankle flexion is shown for each frame.

4. Around the outside of the circle, you'll see red and purple areas. These represent the degree of plantarflexion (red) or dorsiflexion (purple) at that part of the pedal stroke.

You can use this visualisation to understand, and explain to your customer, what's going on with the ankle during the pedal stroke.

It's particularly effective when you are comparing either 2 different captures of the same side of the body, or 2 different sides of the body during the same capture:

You may also like to use this ankle flexion visualization in conjunction with pedal angular velocity.