Many of us are accustomed to the beautifully colored MPA charts by now (and if you aren’t, learn how to enable them here) but you may not be aware of what is possible with the Advanced MPA tab. In this short article, we’ll take a look at the different options that are available, what they do, and how you can make use of them!
Functionality of the Advanced MPA buttons:
Peak Power, High Intensity Energy, & Threshold Power: All 3 parameters of your fitness signature can be directly edited by highlighting & entering in new values
Previous (only available on Breakthrough activities): displays what the MPA analysis would look like using the starting signature (likely what you would’ve seen on your Garmin/workout player when getting a Breakthrough). Clicking on ‘Current’ will return you to the MPA analysis using the new fitness signature.
Refresh: Allows you to view the MPA analysis after modifying the fitness signature parameter(s).
Extract: Runs Xert’s signature extraction algorithm to and returns the exact fitness signature from the activity. Note that the signature extraction will only work with maximal effort data, where there is overlap between MPA & Power. If encountering difficulty with extracting a signature, contact the Xert support team for assistance.
Save: Saves the current fitness signature and locks the signature for the activity. This means that the signature can not be changed unless it is unlocked. Note that a Progression Recalculation unlocks all signatures and should only be performed when absolutely necessary.
Unlock (only available for locked activities): unlocks the signature from any progression updates. N.B. Activities can also be unlocked by clicking the lock icon on the Activities Table.
Important Note: Retroactively adjusting and saving an activity will cause a “trickle down”, where all activities completed following that activity will be re-analyzed starting with the updated fitness signature in this activity.
Moving the slider to the right will show the activity analyzed with the updated (current) signature, as a result of the breakthrough. Moving the slider to the left will show the activity analyzed with the starting (previous) signature. Note that this should match what you would have seen on your Garmin/Android/iOS device in real-time.
How to Use Advanced MPA – Manually Adjusting Fitness Signatures
If the starting signature for an activity is dramatically underestimated, Xert’s extraction algorithm will assume the data is invalid (see example below). If the data is valid, use Advanced MPA tab to manually increase PP, HIE, and/or TP and pressing ‘Refresh’ until there is only a little overlap between MPA & Power. When only a little overlap is present, you can re-run the extraction by selecting ‘Extract’. If the system is able to extract a valid signature, you can press ‘Save’ to Save and Lock the activity.
Notice how this athlete’s signature was likely greatly under-estimated, since they spent nearly 45 minutes “above” MPA! The extraction algorithm has a difficult time extractive a valid signature. In this situation, you can use Advanced MPA to increase the fitness signature parameter(s) until there is only a little overlap of MPA and your power output (shown below).
After manually increasing Threshold Power up about 10% at a time, there is minimal overlap between MPA and Power. From here, you can select ‘Extract’ to run the system’s signature extraction. If the extraction is successful, you can Save & Lock the signature.
If a maximal effort sprint was very short (< 5s), it’s possible that the sprint might not register as a breakthrough on Xert – this is intentional behavior which prevents data spikes from your power meter from skewing your fitness signature. If the sprint data is valid and no breakthrough was recorded, you can use Advanced MPA to increase Peak Power to the highest 1 sec power value recorded on the ride and Save/Lock the signature.
In this scenario, it would be appropriate to manually increase the Peak Power parameter to the highest 1 sec value recorded on the ride and Save & Locking the signature.