This was fixed, as anticipated, for pre-exiting users but a further change is needed for recent sign-ups. This post will be updated, or removed, when that has been completed. Apologies again,
Ian
There have been a lot of new Crickles sign-ups over the weekend and this has surfaced a bug in the processing overhaul I introduced in February. No information has been lost and all activities should play through correctly by the end of the calc cycle tomorrow evening. Apologies for the delay.
If you’re a regular user of Crickles you’ll have noticed the new Pending page that arrived recently. This arose from a deep change to the way Crickles works. Previously, Crickles would take a once per day snapshot of all users’ activities and run a battery of calculations on them. Many of these calculations require analysis of activities over a long time period and comparisons between cohorts of users. Because of this, it’s not easy to update Crickles in real time. Furthermore, when new users sign up Crickles needs a relatively high amount of historical information as background for current metrics – for example, the Cardiac Stress Score for an activity requires a comparison with historical efforts.
Wherever possible, Crickles uses second-by-second (or near equivalent) data for heart rate and power from users’ sports devices as the basis for analysis. Where this is not available – for example, when the user doesn’t wear a heart rate strap or sports watch – we use machine learning algorithms instead. Getting all of this data for existing and especially new users from Strava requires Crickles to make a lot of calls to the Strava API; not unreasonably, Strava limits this. To an extent, Crickles has always tried to regulate API calls to avoid running into these limits but until recently at times of high load the limits would sometimes nonetheless by met and when this happened Crickles would use its machine learning algorithms in place of second by second data to derive CSS and related output. As a user, you’d see that in these cases CSS numbers would be there but not Normalised Power, Effort Spots and (if you have access to them) or Charts. Fundamentally, this did not affect core Crickles metrics but some users (including me) miss those extra features when they’re not there.
To avoid this Crickles now collects activity data in real time rather than on a daily cycle. This is how we’re able to produce the Pending page, although the extra data collection required for this new page is currently run periodically (generally within 30 minutes of upload) rather than in real time. In addition, there is now also forensic management of Crickles API calls to Strava so that we should never hit an API limit. The main calculation load that updates all of the pages in Crickles other than the Pending page is still done on the daily cycle but this now separated from data collection.
In short, a substantial amount of work has been done to implement changes that few users will notice! However, it’s a better, more robust architecture and it now remains open to Crickles to pull some of the calculations (such as Effort Spots) into near real time in future updates.
The changes were significant enough to risk disruption. I think everything is running smoothly now but if you see anything that looks awry please let me know.
Ian
As many of you have noticed, a new Pending page has been in beta on Crickles. This is now officially live, although changes to its style and operation may yet still be made. This page shows your activities on Strava that have not yet been processed by Crickles. Unlike in the beta release, these do not usually appear instantly on the Pending page but will normally show up within 30 minutes. If Crickles is exceptionally busy this may occasionally take longer.
For each activity on the Pending page you should be able to see headline data like this:
If you recorded your location during your activity you should also be able to select Map from the Data: dropdown to see a zoomable map like this:
If you update an activity on Strava – for example by renaming it – you may see more than one version of the same activity in the Activity: dropdown.
If you have an activity on Strava that does not appear in the Pending page within an hour, and certainly if it doesn’t show up after a calc update (indicated by the Last update: field in the sidebar), please email me (you can use the Contact page) to let me know.
Ian
Anyone who was using Crickles last year may recall that we had a couple of special bonuses pages available in January. One of them is now back for this new year too – it’s the 2023 Top 10 page and reminds you of your hardest rides in 2023 as measured by CSS. There’s a drop-down to select from your top 10 and for each one you get a map of the ride. A unique and especially useful feature is that if you were recording your heart rate on your ride you can see any sections where you were above your sustainable heart rate.
Here’s an example:
While the overall route is shown in grey, the sections in which the heart rate exceeded the rider’s sustainable level are highlighted in red.
It’s possible to zoom in and out of the map using the +/- button at the top left of the map.
This feature is only available to users who have completed the short Crickles heart health survey at https://crickles.survey.fm/crickles-cardiac-health-survey. The page will be present throughout January.
Happy New Year!!
For cyclists using a heart rate monitor and a power meter the Effort Spots page enables you to visualise how much time you spent at different heart rate and power levels on a given ride. This has now been enhanced to show you the exact heart rate and power level where you spent most time on the ride – the hottest spot. This is marked with a small green cross (+) and will typically lie within a hot red region:
You can hover over the cross and it will give you the numerical values for the heart rate and power at the hottest spot – in this case 152 bpm and 228W:
Adding a Reference activity works in the same way as before and now also shows you the hottest spot of that activity as a blue cross:
Again, hovering over the blue cross will show you the numerical heart rate and power values for the reference activity’s hottest spot.
Sometimes the heart rate and power combination where you actually spent the most time on a ride correspond to times when you were freewheeling and the power was zero. Since these points are not especially interesting they are not marked as hottest spots and the highest heart rate / power combination with a positive power value is selected instead. In those cases you may notice that the contours and colour coding indicate values on the y-axis that may exceed the “heat” of the hottest spot.
Garmin sports watches now provide a power figure for running, measured in watts. Garmin note that athletes who both run and cycle will find that the power numbers reported for runs are typically significantly higher than those for bike rides. To avoid running power figures distorting the power curve on the Sustainable Levels page and elsewhere in the modelling, power numbers from running have been removed from Crickles.
From today, references in Crickles to Lactate Threshold Heart Rate (LTHR) and Functional Threshold Power (FTP) are replaced by the terms Sustainable Heart Rate (Sustainable HR) and Sustainable Power respectively. The LTHR-FTP page is now renamed SUSTAINABLE LEVELS. The calculations themselves have not changed but the new terms more accurately reflect their meaning and derivation.
In the case of the Sustainable Power metric, the general usage of the term FTP is variable – see here – and does not always reflect what Crickles measures. In Crickles, Sustainable Power is a measure of the level of power that the athlete can be expected to sustain for an hour on a recent evidential basis. This means that if the athlete does not engage in any effort sessions for a while then the recent evidential basis for the estimate of sustained power will decay and the estimate will start to fall until a new, high power effort is recorded. It is not necessary to do a full hour’s effort to get an updated estimate of Sustained Power: Crickles uses empirical information to determine the relationship between the power that can be maintained over different time windows.
Sustainable Power on Crickles will typically be lower than other estimates of FTP, which usually either define FTP differently or rely on relationships between power over different time windows that we do not see supported by data.
The term LTHR is less contentious as fewer people hold a view about their current LTHR level. However, it enshrines a theory regarding blood lactate that, while it may well be true, cannot be empirically established by Crickles as we never draw blood! Instead, the term Sustainable HR references facts that can be determined on a recent evidential basis and this is what we do. Again, this is done by examining the heart rate levels sustained over different time windows and using empirically-derived data from a relevant population to express the totality of recent activity in an hour-equivalent number.
As before, when we expressed this as LTHR, Sustained HR is preferred to maximum heart rate as the basis for calculating cardiac stress and defining heart rate training zones because it is more stable and more reliably measured.
Cardio Mark recently pointed me to this article that adds evidence to the existence of a weekly exercise ceiling above which, for some people, adding further training hours appears to carry negative benefits for long term health, and in particular for heart health. As you can see from the abstract, the authors find that doing no regular exercise is the very worst policy for long term health but that doing over 10 hours a week of exercise may bring a higher risk of mortality than doing around 2 to 5 hours.
Looking on a quarter-by-quarter basis, the majority of Crickles users average between 2.3 and 4.5 hours per week of exercise, which is right in the sweet spot according to the paper. Obviously this varies over time: if we look at the maximum hours of exercise averaged over a quarter, for the majority of the Crickles population this lies in the range of 5.5 to 10.8 hours. This means that quite a lot of us periodically creep above the exercise volume that the paper finds to be optimal. As the authors point out, genetics, diet and other lifestyle factors also need to be considered alongside raw exercise volume, not to mention the type and intensity of exercise. However, it does look as though it’s worth tracking the number of hours we exercise and giving some thought to whether persistently engaging in very high volumes of exercise, if we find ourselves doing that, may be counterproductive.
Crickles isn’t giving health advice but we are enabling you to quantify your exercise and the Seasonal page has had a major overhaul to enable you more easily to track your exercise volume over time. You’ll see that when you land on it it now looks something like this:
By default, it now shows average hours per week of exercise rather than totals, although this can be toggled back using the Show hours as dropdown in the sidebar.
There are now also hover tips – in the screenshot above, you can see that the user is averaging 2.4 hours per week of High intensity exercise in the current quarter (2022, Q1 at the time of writing). Here High reflects time in zones 4 and 5, Medium reflects time in zones 2 and 3 and Low shows time in zone 1. You can use the Heart rate zones dropdown to see more or less granularity: choosing Z1 to Z5 gives you the same detailed data that was previously given on the Seasonal page. Choosing Effort, Recovery on the Heart rate zones dropdown aggregates the data more, bundling all of time spent in zones 2 to 5 as Effort and breaking out time spent in zone 1 as Recovery for a simpler display:
To see your overall total exercise hours in the simplest way, select Totals only in Heart rate zones:
This shows that this athlete is averaging 8.4 hours per week of exercise in the current quarter.
Previously the Seasonal page only showed exercise time when heart rate was captured using a sports watch or chest strap. To enable you to see all of your recorded exercise time – although only moving time, not cafe time – activities are now included even when heart rate was not recorded. Generally, this time is shown as a grey Unknown heart rate zone, although for the Totals only display, which doesn’t give a zone breakdown, it’s just included in the total. If you’d prefer not to include activities that don’t have a heart rate record you can simply uncheck the Show hours when heart rate unknown? checkbox and they will be removed.
The Sport dropdown is of course still available, enabling you to see time spent in each zone by activity type. For example, you may regularly spend time on yoga for relaxation or do stretching sessions and record these on Strava. If so, you can easily see how much time you spend on these activities by selecting them in the Sports dropdown; then, if you wish, you can subtract that time from the overall total if you think that gives you a better picture of your true exercise volume. Note that time spent on sports such as outdoor cycling will typically involve a reasonable amount of time in zone 1 (a.k.a. low effort or recovery) – for example, when you freewheel down a long descent. Stripping this out of your average hours totals may be misleading as it’s an essential part of the sport and is likely to be included in the leisure-time sports activity figures used by the authors of the paper. It is, however, worth being aware of intensity composition and it is factored into the CSS-based analytics elsewhere in the Navigator.
A number of enhancements have been made to the Timeline page. The most immediately obvious change is that there is now better colour differentiation based on intensity levels. As before, the highest intensity activities are coloured red and the lowest are green but the contrast is now clearer:
Also, all of the values shown in the hover boxes are now rounded to whole numbers or one decimal place.
Other enhancements improve the clarity of information seen when you aggregate the timeline data monthly using the checkbox in the sidebar, where you can also choose to compare your monthly aggregate data with peers ():
Information on each month is now shown as a hover tip, as it is for the non-aggregated points:
The comparison to others is especially easy to see if you use the Compare data on hover control in the top right of the chart area:
When you use this it’s easy to compare your CSS, Hours of activity and aggregate Monthly intensity measures with those of peers:
For example, here I can see that in the chosen July period, while my aggregate Monthly intensity was lower than that of peers, my Hours of activity were higher and this netted out to give me a higher CSS over the month.
You will also notice that while an individual activity with an intensity of, say, 80 is coloured in the orange spectrum, an aggregate monthly intensity of 80 would appear as red. This reflects the fact that we quite often do very hard individual efforts but to be doing even moderately intense efforts every time we exercised throughout a whole month is likely to bring our monthly intensity considerably higher than the usual peer average.
There is a new landing page on the Navigator – called In a Nutshell – that gives a quick overview of your essential Crickles information from the last four weeks. It’s in the form of three blocks. The first shows you your aggregate cardiac stress score over the period:
The question of how much exercise is optimal is largely a matter of judgement and part of the value of Crickles lies in determining a cardiac stress measure in a credible and consistent way so that you can meaningfully compare your volume of exercise with that of your peers. The big number at the top of this block – 3,019 here – is the sum of your cardiac stress score over the past four weeks. The colour of the block – red in this example – indicates how this value (3,091) compares with that of other Crickles users who are closest to you in age. This is also explained in the sentence at the bottom – in this example the value of 3,091 is “Higher than most age group peers”. The bars in the block show your cardiac stress score for each day, as indicated here by the hover tip over 29th October.
More information on the derivation of these values can be found on the CSS Factors, Relative CSS, Timeline, CSS by Sport and Activities pages.
The second block gives you information about the level of heart rate that you sustain during exercise, summarised in the Threshold Heart Rate number at the top (158 beats per minute in this example):
This threshold rate is determined by looking at your heart rate over different time windows – although it’s termed Lactate Threshold Heart Rate (LTHR) Crickles knows nothing about your actual blood lactate levels – and is expressed as an estimate of the highest heart rate you have sustained or could sustain for an hour. This changes adaptively over time along with your exercise. The chart on the block shows how your threshold heart rate has changed over the past four weeks. Again, the block colour and the text at the bottom indicate how your current threshold heart rate compares with that of your age group peers.
To drill into this further, the LTHR FTP page shows you the chart more clearly over a longer time horizon. Also, if you sort the Activities page by descending Intensity, any activities for which Intensity is over 100 will be where your threshold estimate increased. The HR Zones page shows you proposed training zones derived from your current threshold heart rate.
The final block draws attention to any unusual heart rate readings of particular kinds over the past four weeks. Often or usually it will look like this:
Occasionally though you may see something like this:
If you see the message shown here then there was something suspicious about your heart rate reading on the identified date(s) suggestive of a faulty strap. Alternatively, you may be alerted to one or more “irregular” activities. This is detecting a different pattern of irregularity in the heart rate readings. It is reasonably common to see one of these now and then; it is less common to see more than one in a four week period. For example, at the time of writing 3% of athletes on Crickles had two or more activities flagged as irregular in the last four weeks. This is not in any way a medical diagnostic and the pattern detected would not per se be judged medically significant. Moreover, the absence of irregular readings does not imply in any way a clean bill of cardiac health and if you are concerned about your heart health you should seek medical advice and not rely on Crickles as a proxy. Nonetheless, a high number of irregular readings is associated with a higher reported incidence of heart rhythm issues.
Details of probable strap issues and irregular patterns can be found on the Activities page. If you want to see the heart rate curve that triggered one of these readings, you can do so on the Charts page, if you have access to it. If you have completed the Crickles survey and want to see more information on how your frequency of irregular readings compares to that of others with and without arrhythmia, you can find this on the Irregularity page.
You may notice that the default date range on all pages for which date range is present has been changed from the past six weeks to the past four weeks. This is in part to make it easier to compare the information on the In a Nutshell page to the more detailed information offered by those pages.
