Is CTL (Chronic Training Load) A Good Measurement For Tracking Fitness And Performance
CTL is like a mileage reading in a car, it doesn’t show you the route, weather conditions, passenger distractions, destination type, speeds, type of road, congestion etc… you’ve been on, occurred and will occur. Two very different paths may have been taken in two very different machines to produce the same mileage (CTL figures) and so two different performances will occur at the final destination point.
Why CTL (and all other metrics on performance management apps) should be used cautiously/wisely:
1) External stressors
-Lifestyle stress e.g Extremely stressful day at work, young children, sleepless nights the list goes on. All these produce a form of stress, sometimes in huge levels, none of which are recorded by a metric on the performance management apps.
-Emotional stress Psychological, often resulting from the above and many more complex factors (a whole other blog post) raise cortisol (stress hormone) levels and are not recorded as a metric on the apps.
Solution- Use common sense. Have a good instant communication system with coach. Relay all your external stressors across. Your coach should then interpret your data accordingly with these in mind. (see my approach at point 5)
2) Physiology
-Using Heart Rate as determinant of TSS is often not the best but not everyone has a power meter for the bike, and although running power is now available its effectiveness is questionable and swimming no such power reading is available.
Why is Heart rate (HR) is sometimes ineffective?
-Caffeine can cause a raised HR – so greater TSS even thought the specific training effort may be less than the TSS indicates. (There are various types of responders to caffeine and its effect on performance based on genetics. This will be the subject of another future article. -Illness can cause an increased HR and skews the results in general. Low lying illness may also skew TSS based on HR. Furthermore two bouts of Illness may set you out for the same period and so a same reduction in your CTL figures will occur however the two different illnesses may have had a significant difference on your body and its ability to pick up training.
-Physiology – low stimulation environment , e.g sometimes training slightly fatigued on your own, low/high levels of external stimulation all have an effect on HR and resulting TSS score. -Fatigue levels- high fatigue levels can keep your heart rate lower and unresponsive hence lower TSS score.
-Temperature – Heat can also can an increase in HR and so a greater TSS may result.
-Power is also not always effective in relation to TSS – e.g two athletes may respond and cope with two workouts very differently. One may be stressed a lot more doing higher intensity intervals than the other (e.g. their genetic make up and muscle fibre types differ) and so although both may have the same FTP test results and the exact same interval readings on their workouts and so the same TSS results but one may take significantly longer to recover than the other.
3)Type of activity
-e.g Strength work may maintain a low HR and so low TSS result yet the muscle damage occurred may take an athlete a long time to recover from.
-Genetic variations and a persons response to a specific workout (see point (2) above).
4)Inaccurate zones set without conducting your zone tests in a laboratory like professional athletes do with detailed Vo2 and O2 readings etc the tests most amateurs do will always be somewhat inaccurate due to factors such as pain tolerance, external stimulation and the athletes varying fatigue levels going into the test.
5)Other things to bear in mind
High CTL doesn’t necessarily mean better performance on the day.
How has the CTL figures being generated e.g what type of training have you done, how has your body absorbed this training ,genetic variations , equipment , technique , periodisation, the list goes on . To summarise the above see the analogy I used at the start in relation to CTL being like a mileage reading.
6))My approach
I use performance management chart metrics CTL, ATL, TSB, TSS,IF as simply just that ,another metric, another factor, another measurement in the plethora of metrics and gages to determine training and its effect.
Developing an acute awareness of the internal goings on inside your body is key. This a skill that I believe takes time and is almost never ending. I believe what makes some of the most elite athletes remain at the top is mastering this skill and more importantly how this is relayed between the coach and the athlete and then implemented immediately into their training.
Fitness is multifactorial. Due to the diverse nature and complexity of our bodies its wise to always use the figures above cautiously. They do need some respect but on the other hand being sensible and using common sense and communication is often the most underrated methods of analysis between coach and athlete.