Gather Data and Initial Analysis

Now that your power meter and head unit are ready to use, it is time to gather data and initial analysis to start looking at what it tells you over time.  Looking at performance over time allows to identify improvement opportunities and eventually create and follow your power based training plan.

For time based trends, you will need to gather data for several days. One of the analysis tools we will use, the PMC (Power Management Chart) needs ideally at least 6 weeks of data, though you can start looking at results before that.

This is may be a good time to download Golden Cheetah, unless you have access to a similar power data analysis app.

Note: This post is part 4 of 5 of a series on how to start training with a power meter. If you came here as a result of a web search, make sure to go the starting post to take full advantage of the series. If you have not done so yet, please read the section About Training with Power, where we explain our approach to sharing the Training information in this website.

 

POWER METER DATA ANALYSIS WITH GOLDEN CHEETAH

There is so much to extract from a FIT or TCX file to get the most of a power meter that a good web platform or software program are needed. There are many to choose and select from and most of them require a fee to have full access.

In December 2021, I became aware of Golden Cheetah (https://www.goldencheetah.org/) a free, multiplatform program for power meter analysis.

The initial set up process is easy and fast. Once you are ready, import your power data files. There are several options to do so, depending on where you store them, including direct imports from Strava and Garmin Connect.

Once your data is loaded, you will be ready to better understand your fitness by looking at an amazing array of charts, tables, indexes and metrics.

The amount of information that this program shows is overwhelming and intimidating. But, after reading several books on power based training and having some knowledge of the terminology, I had an idea on what to look for. The two most important performance charts are the PMC chart and the Power Curve.

PMC (Power Management Chart) from Golden Cheetah

This image shows a PMC chart for about 4 weeks of training. Though not yet within the ideal 6 weeks (42 days), it shows good enough information to get started.

Four lines can be seen. All of them are derived one way or another from the TSS of each session. The magenta line is called Acute Training Load, that in simple terms represents the load your body is receiving and thus the fatigue. Each time you train, your body fatigues and that is what the graph shows. Normally, it is based on the TSS of the last 7 days of exercise.

The blue line called Chronic Training Load, represents your fitness and is calculated based on the TSS of the last 42 days of training. It shows how you are improving (ascending trend) or decreasing (descending trend) your fitness.

You will notice that the ATL “pulls” the CTL. This represents one of the most important principles of Overload. In order to improve the body shall be stressed to a higher level than it is used to, then allow for it to recover, where it will get stronger to be able to face the new stress load.

The yellow line represents the Training Stress Balance which is the difference between CTL and ATL and is used to measure your Form. Form means being in shape, that is fit, but rested as well so that you can have a great performance. As close as it gets to Zero, the better form you have.

So, eventually, to be ready in your best Form for an event, you will have to decrease your training load, which will be seen as a descending ATL, allowing the body to rest, until the Training Stress Balance gets as close to Zero as possible. Then you are ready to go full power on that event.

Finally, the green line is the RR that represents the trend your CTL is growing at.

This is the most important graph to watch and have control of your fitness. It is all about having a balance between stressing your body, letting it rest to recover and get stronger, and plan to be in Form for that important event.

The Power Curve from Golden Cheetah

Also, for the same period of the PMC chart above, it allows to see where your strengths and weaknesses are in relation to the seven power zones that were calculated after getting your FTP.

The vertical axis has power values while the horizontal has time. This graph plots the amount of power you have generated for certain time periods, shown in the X axis.

The blue dotted line represents the ideal power you could generate along the seven zones as calculated by the software. The blue continuous line represents the actual power you are generating. The gap between the 2 represent the potential for improvement in a specific zone.

The shadowed graph shows what zones power has been generating. It shows a predominance of Zone 6, followed by zone 3.

This graph can help guide your training depending on your goals. If you look for long rides both in distance and time, such as XC or Marathon, then you should be training predominately in zones 2 to 4. If you are more on short rides with lots of sprints and hard efforts, then you should focus on zones 4 to 7.

What is a strength or a weakness depends a lot on the type of mountain biking you are doing, but it is a good practice to spend some time in each.

 

POWER METER DATA ANALYSIS WITH GARMIN CONNECT

The Garmin Connect app, also provides some helpful information in its Performance Statistics.

Garmin Connect FTP over time chart

Shows the performance of your FTP along time. FTP, besides being the base to calculate the training zones, is also one of the major performance improvement metrics. If your FTP increases, your fitness is improving. That is why it should be measured periodically.

 

Garmin Connect VO2

Per the description in Garmin Connect, “VO2 max is an indication of cardiovascular fitness and should increase as your level of fitness improves”.

Garmin Connect Lactate Threshold.

Threshold Heart Rate could be considered as the FTP equivalent for heart rate based training. It is used to calculate the heart rate based training zones.  A decreasing value (improvement) means you can apply greater power at reduced heart rates, a sign of fitness improvements.

 

 

and the overall fitness performance trends

 

SUMMARY

The data analysis of the first few days of using a power meter start to show performance trends to identify where you should focus your training towards your goals.

With this data, it is now time to build the detailed, day to day training program.

 

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