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Why We Don’t Use TrainingPeaks at VO2maxCoaching.

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Why We Dont Use TrainingPeaks at VO2maxCoaching.


TrainingPeaks – We Make Coaching Easy”

At least, that’s their motto.

Unfortunately the coaching of distance runners is not even close to being ‘easy’. Coaching is not a science, although coaching is holistic and to be a coach you do require a deep understanding of multiple disciplines. These include anatomy, physiology, psychology, nutrition, the history of training, biomechanics, and strength and conditioning.

Coaching cannot be learned by attending a few lectures, taking an open-book test, or completing a ‘no fail’ online course. UESCA certification doesn’t mean you’re certified to do anything, particularly coach distance runners! And like UESCA, the TrainingPeaks ‘University’ exists simply to make money for those providing the ‘courses’. 

Coaching is an art; it’s a craft. It takes decades of reading, practice, self-experimentation, mentoring, and commitment to become an even moderately competent coach. It takes decades to earn the privilege to ask athletes to pay you money to be coached by you!

Coaching distance runners is intuitive. It’s not a simplistic enterprise composed solely of writing training plans, analysing workout splits, and describing changes in isolated performance metrics. Physical fitness cannot be defined, nor can differences be detected, by means of a few proxy measures obtained during limited physiological testing. The idea that a coach needs statistical significance or a double blind placebo controlled study to find the actual truth is false. Regardless of the validity of their particular algorithm, no watch can tell a coach when it’s appropriate for athletes to work out, and no ‘wearable’ tech can comprehend the intricacies and dynamism of athletes.

Has your new ‘coach’ asked you to immediately buy an expensive ‘smart’ watch or an Oūra ring or a running ‘power’ meter? Was their first act as your ‘coach’ to tell you to consult with a psychologist or nutritionist, or undergo VO2max testing, lactate profiling, fuel utilisation testing, or sweat testing? If so, that’s a clear indication that they probably don’t understand the sport they are coaching and are a long way from developing their own principles.

Coaching is about communication and building relationships. Each athlete represents a unique amalgamation of physical, mental and contextual elements that defy simple algorithmic description. A good coach must therefore spend time exploring the background and personality of each athlete, and developing a trusting and caring relationship in which the athlete has the freedom to explore and perform. Only then will the coach be free to make changes to an athletes thought process and lifestyle behaviours in order to balance the training ‘dose’. Arriving at this point with an athlete is tougher than it sounds. Inertia must be overcome. To simultaneously shift multiple areas of competency takes time and the kind of relentless enthusiasm and drive which few possess.

Coaching also requires humility. Good coaches foster independence and self-sufficiency in an athlete. And a good coach knows when to shut up. Growth comes from letting athletes wrestle with their own thoughts and actions and make mistakes. Coaching is not about you and your reputation, your accolades and status, your popularity, your ‘followers’, or your brand. It’s about the athletes.

A well-known influencer and podcaster who promotes TrainingPeaks as the ultimate resource for distance running coaches, wrote recently without any sense of irony or shame: “I often am asked: how many athletes do you coach? At any one point in time, I work with between 35-40 athletes. That number is very deliberate. How did I come up with that? It takes me about one hour per week, per athlete, to fully complete all my coaching duties for them.”  


Why We Dont Use TrainingPeaks at VO2maxCoaching.


One hour per week per athlete? I’m not sure what this quack is up to, but it definitely is not coaching. However, it does seem that some runners are willing to shell out up to £1000 per month on scammers like this who have no idea what coaching is all about. So maybe TrainingPeaks ought to change it’s motto to:

TrainingPeaks – We Make Coaching A Business”

The hubris we see in the business world has no place in coaching. Yet TrainingPeaks is popular among individuals with no experience of coaching who want to start a coaching ‘business’ because:

(a) there’s no barrier to entry, no baseline of competency required, and so it therefore allows charlatans, scammers and anyone intent on having a brand (rather than actually helping runners) to ‘coach’ 30, 40, 50 athletes concurrently;

(b) it makes up for their lack of understanding of the craft of coaching by providing them with an array of complicated-sounding performance measures (or ‘metrics’) that create the illusion of coaching acumen and proficiency;

and (c) it permits them to offer various ‘packages’ in order to fool runners into believing that it’s possible to coach effectively using data analysis alone, or with very little direct communication. 

TrainingPeaks claims that the more quantitative metrics you provide via your watch or wearable, the greater your performance gains will be. However, technology is only useful if it ends up solving real problems for athletes. Just because something can be measured to a few decimal places, it doesn’t mean that measurement is accurate, is useful, or that a coach should emphasize it. Descriptive data should never be treated as prescriptive advice. Whoop and Stryd are obvious examples and coaches need to be a little more savvy no matter how fancy the tech.

Also, before coaches advise athletes to use a certain technology, they need to remember that many athletes are perfectionists and that it is perhaps best not to present athletes with data that is likely to be be unreliable because it’s impossible to ‘unsee’ data! Many athletes have a tendency to obsess about stats, along with a bias towards exploring all the latest maginal gains and technological short-cuts to improve performance. Manufacturers of wearbles take advantage of these traits and make wild claims about their products that are not backed up by credible evidence. For example, an athlete might feel that they’ve had a great nights’ sleep, but their sleep tracker indicates poor sleep quality. All that this is going to achieve is to make the athlete anxious and affect their mood throughout the day!

The line between helpful information and noise has become burred. A distance running coach is not a high-tech coach. When it comes to training prescription and analysis, a good coach does not require a shit-tonne of metrics: Chronic Training Load, Acute Training Load, Functional Threshold Pace, Training Stress Score, Intensity Factor, Training Stress Balance, Training Impact Score, Efficiency Factor, Running Effectiveness, Dynamic Functional Reserve Capacity, Normalised Graded Pace, Pace Heart Rate Decoupling. What a pile of crap. This mudslide of metrics used by TrainingPeaks is reminiscent of the jargon used in the financial sector. Bankers love to use confusing terms to make you think only they can do what they do – to make you feel stupid! 

Worse still, most of the metrics used by TrainingPeaks’ algorithms to produce their endless array of ‘charts’ are at best hopelessly unrealiable, and at worst utterly meaningless. This is because these metrics originate from devices whose reliability and validity is highly questionable. 

Take ‘running power’. According to manufacturers of ‘running power meters’, they provide an exact, real-time measure of mechanical power or metabolic demand. However, these devices employ accelerometer and GPS pace data and complex algorithmic computations to produce an implied estimate of running ‘power’. So to describe what is being recorded as ‘power’ is very cheeky, because it simply is not. Unlike in cycling, in running it’s impossible to measure external forces because of an absence of an intermediary between the athlete and the propulsive application of force at the ground.

In fact, the concept of power actually has no useful intrinsic definition in running. Running entails negligible external mechanical work. It involves positive work (pushing off with each stride) and negative work (braking on landing). Elastic energy stored in the Achilles tendon and other tissues also makes a significant contribution as up to 50% of power required for each step is released as these tissues stretch upon landing and subsequently recoil to aid pushing off. Moreover, the power contribution of each of these changes when you run uphill and downhill or switch from running on roads to trails! No single device can measure all these contributions in running. And this is why, to date, there is no scientific evidence regarding the validity or reliability of running power meters, and no meaningful insights on the use and interpretation of running power data in endurance runners.

Then there’s heart rate variability (HRV), which suffers from similar issues of reliability and validity as running power. Over the last few years HRV has become seen by some as the ‘gold standard’ in measuring recovery and readiness in the human performance industry. However, the accuracy of wearable optical heart rate measurements using photoplethysmography (PPG) has been questioned extensively: especially during exercise in the cold or the heat, during high-intensity exercise, and during trail running (which is an inherently dynamic exercise that produces a variable, rather than steady state, heart rate response).

Therefore, if heart rate data is unreliable, it’s unrealisitic to assume that something as sensitive as HRV can be measured with any degree of validity or reliability with the majority of consumer-oriented wearable sensors. Athletes and coaches must always always bear in mind that to measure HRV accurately an electrocardiogram must be used, or failing that a good quality chest strap monitor such as the Polar H10 (which is unreliable for higher exercise intensities).

Even using the very best technology available, HRV data is not actionable in terms of guiding training because running is not the only stressor to influence HRV and non-training stressors  impact on HRV in ways that are yet to be fully understood. The interpretation of HRV data is highly problematic and so complex that this biomarker requires many more years of rigorous investigation before coaches should use it to prescribe training or dictate recovery. It’s simply not yet the powerful, impartial measure that TrainingPeaks wants it to be! Running coaches would be wrong to try to use HRV in any capacity to try to ascertain an athlete’s readiness to compete, state of fatigue, fitness and form, level of stress, adaptation to training, or susceptibility to injury or illness.

The biggest issue with HRV is performing repeatable and consistent (and therefore comparable) measurements in the real world. For example, HRV is impacted by what and when you eat and drink. HRV changes throughout an athlete’s sleep cycles. Taking an HRV reading first thing in the morning (as many coaches advise) is inappropriate as it may appear artificially low or high (depending upon sleep quality and duration and when during an athlete’s sleep cycles they actually wake up).

And to muddy the water even further, there’s a more troubling confounding factor when it comes to interpreting HRV. Despite what many coaches seem to believe, it’s wrong to assume that high HRV readings (or increasing trends) are always good, and that low HRV readings (or decreasing trends) are always bad. A high volume of low and moderate intensity aerobic work is likely to cause an increasing HRV trend. Several studies have reported increasing HRV trends in ‘overtrained’ athletes predominately involved in endurance sports. This is something that all ultra-runners should bear in mind! Similarly, during phases of high intensity training (with minimal low intensity work) a progressive decrease in HRV can occur despite no meaningful increase in levels of fatigue.

Determining the reliability and validity of wearable devices is an issue that has been raised constantly in systematic reviews, but continues to be under-studied. This is because of the huge time investment needed to measure reliability conflicts with the desire by tech manufacturers to get their produt to market. So why does TrainingPeaks embrace what is essentially pseudoscience?

Well, apart from the desire to manipulate the science for commerical purposes and create a highly profitable template for a business, that’s a simple question to answer. The world is uncertain and chaotic and there’s a comfort in prediction. TrainingPeaks provides a black-and-white approach to trend interpretation. Many athletes and coaches are drawn towards the aforementioned “high = good, low = bad” interpretation of stress and fatigue. TrainingPeaks metrics represent a quest for certainty where it simply does not exist. The analysis of quantitative data, no matter how unreliable, provides a sense of control; it provides an answer where, in reality, there is no answer. 


Why We Dont Use TrainingPeaks at VO2maxCoaching.


“How do you feel?”

The only way to determine readiness to perform is to ask the athlete, how do you feel? And then listen to the answer. No device, no algorithm, no amount of data can describe or predict the answer to this question. Numbers are one-dimensional, athletes are three-dimensional, and performance is multi-dimensional. The art of coaching is the art of being present: of talking, listening, questioning, understanding, and caring. And it’s the art of developing a ‘filter’. Athletes are terrible barometers when it comes to knowing what they are ready for. Their motivation is so high, and they are prone to so many biases, that they do not necessarily listen to what their own body is telling them. It’s a coaches job to help guide this process by looking into the athlete’s conscious mind and reading the story that’s being constructed. Is the athlete telling you the truth or merely what they assume you want to hear? However, thanks to an over-reliance on data and technology, this is becoming something of a lost art. 

The most important data isn’t objective data from a lab test or an over-priced watch, it’s verbal. Subjective measures have been shown time and time again to reflect acute and chronic training loads with superior sensitivity and consistency than objective measures. To obtain actionable subjective verbal feedback from an athlete, the coach needs to be able to ask the right questions, which is a skill in itself. Equally, athletes must also develop good communication skills. They must learn to process and share their experiences and feelings; their perceptions of mood, stress, and recovery. They must learn to describe how they feel (rather than relying on how their watch is telling them they feel). This is why a coach is first and foremost a teacher (whether they think of themselves as such or not).

There’s one very important but often undervalued product of requiring athletes to write about their experiences and what they are feeling on and off the track. Expressive writing, in particular about failures and other troubling experiences, alters brain activation in areas linked to processing negative emotions and can lead to positive outcomes. Writing enhances well-being, increases resilience, helps athletes cope with stress, and reduces depressive symptoms. In other words, writing acts as a kind of therapy (except writing creates a degree of separation and is far less threatening than talking to a therapist) and is a great way to confront things we often try to compartmentalise or ignore and make sense of them.

The involvement is purely passive if all an athlete does at the end of their workout is upload data from their watch to TrainingPeaks. The human element is lost because TrainingPeaks is a black box and by over-emphasizing metrics it places a barrier between coach and athlete. A coach-athlete relationship that is prescriptive, dictatorial and businesslike replaces one that needs to be humanistic and learning-based. The coach isn’t teaching. The athlete isn’t learning. And vice versa. Injuries and ‘burn-out’ are becoming more and more common, and this largely due to the ‘dumbification’ of coaching, to an over-reliance on data and a lack of communication between coaches and athletes.

So by way of conclusion, below are a few examples of the types of questions a good coach should be asking athletes daily (in addition to whatever quantitative data they claim to be analysing). Collectively termed ‘subjective measures’, the answers to these questions will indicate to the coach an athlete’s perceived physical, physiological and psychological well-being and readiness to perform. How an athlete perceives themself will have a big impact on hormones, and hence subjective measures accurately reflect changes in athlete well-being.

In addition, subjective measures help the coach in understanding an athlete’s motivational drivers and mindset, their level of buy-in. Performance depends 100% on this baffling, ephemeral phenomenon called motivation. Understanding the factors that might influence an athlete’s motivation requires constant questioning. Motivation cannot be measured and is an uncontrollable, quickly fluctuating, disturbing variable which may at any time completely alter the performance regardless of physical or physiological state.

(1). How many hours do you estimate you slept? What was your perceived sleep quality (i.e. continuous or disrupted)? How fast did you fall asleep (i.e. immediately, 5-20mins, or a long time)? How refreshed did you feel in the morning? How is your libido (men only!)? What were your perceived energy levels throughout the day? Did you nap during the day? Despite the growing range of wearable sleep trackers available these days, perception of how they slept remains the most accurate way for athletes to measure sleep quality. Sleep consistency, which may be seen as training circadian rhythms, is as important as training the heart and lungs! Athletes require a lot more sleep than non-athletes: ideally 10-12 hours per night during a hard training block. Sleep helps to harness hormones. Recovery from, and adaptation to, training occurs during sleep. Sleep permits adaptive immune system recovery. Sleep disruption and insomnia remains one of the best known markers for the detection and prevention of ‘overtraining’ or ‘overreaching’. Determining an athlete’s chronotype is also very useful – ‘night owls’ ought to train in the evening and avoid very early morning sessions; while the ‘larks’ should avoid late evening workouts.

(2). What was your directly diet before and after training? What did you eat and drink during the long run (i.e. total calories and how often)? What did you eat throughout the day? Did you eat a wide variety of fruit and veg and drink lots of water and get a proper meal at lunchtime; or were rushing around all day and only had the time to grab a few snacks? Did you experience a decrease (or increase) in appetite? It’s vital an athlete understands how their food choices affects their training. Low carbohydrate intake in particular will have a potentially catastrophic impact on hormones and health. Historically, very few ‘overtraining syndrome’ studies have actually controlled athlete diets or measured habitual food and fluid intakes and it’s the coaches job to ensure that the athlete is getting optimal nutrient and caloric intake to allow recovery. Even small within-day energy deficiencies (300–400 kcal per day), which usually do not impact immediate health outcomes, can become clinically significant when multiplied across months. Food timing before a workout is also critical, as is the ‘recovery window’. An athlete must get sufficient carbs and protein into their body within 20 mins post-workout. Caffeine is an interesting subject and somewhat misunderstood. Caffeine promotes alertness by blocking adenosine, a sleep-inducing chemical. During deep sleep, adenosine is recycled and levels are reduced in the brain. High caffeine levels in the brain before bedtime will impact on deep sleep. Also, most distance runners have a problem with iron, so the coach needs to monitor this constituent of the diet very carefully.

(3). Did you feel fresh before training and couldn’t wait to get out of the door? Or did you feel some ‘tiredness’ and a ‘lack of energy’, and were you procrastinating, before training? And if you did feel physically or mentally fatigued before the workout, why was that? What sort of mood were you in today (irritable or relaxed)? What did you get up to at work today? What were your perceived stress levels throughout the day? Is anything in particular worrying you right now? Coaching requires a high degree of sensitivity to all sources of stress. Occupational cognitive demands and stress within the athlete’s family or social support network add to the physical and mental stresses of hard training and competition. Monitoring sleep, mood, stress levels, and nutrition together allows the coach to answer the question: what is the athlete doing to recover and how are they recovering? A workout does not start when the athlete laces up their shoes and sets foot on the road/trail/track. It starts long before then. If the athlete is stressed right before a hard workout, reduced motivation and willingness to exert effort is likely, meaning there will be less adaptation to training than if the athlete goes into the workout ‘fresh’. Mental fatigue limits exercise tolerance through higher perception of effort. Emotional stress shifts what workload an athlete can handle and adapt to. Athletes tend to adapt less and get injured more during high stress periods (e.g. during exams, changing residence, or starting a new job). This doesn’t mean an athlete must stop training when stressed, but it does mean the coach will likely have to reduce workout dosage. For example, it can take a week or more for perceived exertion, fatigue, sleep quality, sociability, and feelings of distress to normalise following a tough period of exams. Therefore, it is a mistake to ignore and attempt to ‘train through’ these very stressful life events.

(4). Do you feel like you performed well in the workout, or poorly? In terms of effort, was the workout a real struggle, was it challenging, or was it easy? Were you slowing down towards the end, in the final few reps? Did you finish a disheveled mess, on the brink of failure? Could you have kept on banging out intervals at that intensity for another 20 minutes? Or in the case of a hill run, how much time was spent hiking compared to running? The ‘Session RPE’ (Rating of Perceived Exertion) – that is, the subjective intensity of a training session – is THE MOST USEFUL TOOL FOR MONITORING TRAINING. The RPE is useful not only for hard workouts. It is often the case that on days the coach intends to be ‘‘easy,’’ athletes often perform meaningfully longer and/or more intense training. Moreover, the coaches focus shouldn’t be on simply whether a workout is completed or not. Rather, it should be on what occurs DURING the workout. The coach needs to understand where within the workout was an athlete struggling, and where they were succeeding. When a coach writes a workout, they are essentially making a prediction. And the athlete’s fatigue signature tells the coach how accurate that prediction was. The answers to these questions allows the coach to reassure and reinforce, and improve their ability to predict what is an appropriate workout for that particular athlete on any given day. 

(5). In terms of your rhythm and timing, how was your breathing and how did you feel you were moving? Did you have a good change of pace or were you stuck in bottom gear? Did you feel relaxed as you glided effortlessly up the hill or were you grinding your way through each hill rep? Did you feel smooth on the descents, or was your descending forced and rigid, were you nervous and having trouble to getting into a nice flow? When did fatigue really start to kick in and impact on your mechanics? How athletes feel they are moving provides more insight than GPS data, physiological parameters, or the latest proprietary stress load algorithm ever can. The conscious sensation of how hard one is driving the locomotor muscles (leg effort) and the conscious sensation of how heavily one is breathing (respiratory effort)  are the most important components of perception of effort.

(6). ULTRA RUNNERS ONLY!!! If you were running with poles, how was your rhythm and timing? Did you feel comfortable, relaxed and efficient with the poles? Or did you feel burdened by them? Did ground conditions impact on pole use? Using poles to run increases oxygen consumption and thus energy expenditure, and it is therefore demanding for the metabolism. This increase could be explained by an increase in upper body and trunk muscle activation. At the same time, the lower limb muscles experience a significant relief through the reduction in muscle activation and ground reaction forces. So it’s important to know if, subjectively, the athlete feels they are moving well and improving their ability to use poles (i.e. if RPE is higher, lower or unchanged when compared to not using poles).

(7). How were the legs responding during the workout? Did you feel ‘bouncy’ and have ‘pop’ in your legs, or did you feel ‘flat’? This relates to the idea of muscle tension (which helps to explain why the legs often feel amazing one day and unresponsive the next). Understanding muscle tension is central to recovery and getting an athlete ready to race. This is one reason why good coaches use regular sprint drills and strideouts. These exercises are a good test of how much ‘pop’ an athlete has in their legs (even on easy days) and how quickly an athlete is recovering from hard workouts. Mr Koop the well-known influencer and podcaster has stated: “I need to evaluate current training and analyse the complexities of each workout. Every file gets analyzed, some of that analysis is very quick and easy, if it’s a recovery run or something like that”. Wrong! Feedback from a recovery run is just as pertinent as feedback from a long, hard workout. And after a layoff, even low-intensity training can cause pain and discomfort. While an athlete may take an easy day and ‘switch off’, a coach never should!

(8). What is your perceived level of muscle soreness/weakness after tough workouts (i.e. those that are physically or mentally challenging)? The greater the stress of the workout, the greater the overall muscle recruitment, and the greater the potential for muscle damage and soreness, therefore the need for longer recovery time before the next demanding workout. It’s crucial to know what type of workouts produce tightness, soreness or weakness, how long that soreness lasts, and whether or not the soreness produced by a certain type of workout reduces as the season progresses. What the coach is hoping for is a negative trend in reported soreness/weakness, which indicates that there is adaptation (as opposed to continued soreness, which indicates ‘staleness’).

(9). Did you enjoy the workout? Did you feel really focused going into the workout and were you looking forwards to it? Or were you dreading this workout; is it one you never look fowards to doing? There are no magic workouts, so if an athlete isn’t psyched by a particular type of workout, motivation may suffer unless the workout is altered or reframed in some way. Discipline (i.e. doing something one doesn’t want to do as if one is highly motivated) may go out of the window. Motivated runners pay attention to detail, and should never get tired doing the fundamental tasks that support their endeavor. They find enjoyment and stimulation in the most mundane tasks. Repetition does not bore them. So if an athlete does find a workout ‘boring’, all that may indicate is that the coach has failed to teach them the ‘why’ behind the workout.

(10). Did you have any localised muscle fatigue or discomfort when running (such as old injury symptoms) and, if so, what was the level of perceived pain? Did the pain increase or reduce during the run? Did you have any illness symptoms? Discomfort or other conscious sensations experienced during endurance exercise, such as muscle pain, a ‘stitch’ or localised muscle fatigue, are a very different thing to perception of effort. While locomotor muscle fatigue will probably reduce endurance performance (obviously), it may also indicate the presence of a weakness that may need addressing with strength training. And pick up on low level physical pain early enough and a coach may prevent, for example, a slightly stiff achilles becoming acute tendonitis and six weeks in the pool! The same goes for any illness: pick up on the symptoms early enough and the coach may prevent a head cold turning into a chest infection. The immune system is sensitive to stress – both physiological and psychological.

(11). Did you experience any gut problems today? If so, was this during the day, or during and after training? Vigorous or prolonged exercise poses a challenge to gastrointestinal system functioning and is associated with digestive symptoms. A well functioning gut is key in contributing to athlete performance and health. Issues of malabsorption of nutrients and subjective gut discomfort will impact on everything from immune function to energy levels during training and racing.

(12). Did you train alone or did you train in a group today? This can make a huge difference to workout splits and perceived effort levels. For example, if an athlete is running with a slower runner this could have a big impact on the workout goal. So it’s crucial that if the athlete is training with other people, the coach understands group dynamics. 

(13). What was the weather like and did it affect how you felt during the run? How were the underfoot conditions and the terrain? Factors such as thermal discomfort often explain why workouts don’t always go so well, or seem harder (or slower!) than they ought to be. They may also highlight an athlete’s weaknesses and may indicate how well they can ‘rise to the occasion’ during tough conditions.

(14). Did you feel like there was a good connection between the workout and the race you are training for? Did you feel somewhat ‘disengaged’ because the workout seemed ‘excessively difficult’? Training is not just about physical ‘conditioning’, it’s about mental preparation for the race and developing coping strategies. In a race the athlete is often entering a risky, unpredictable environment. So not only is it important that an athlete replicates as many physical aspects of the race as possible in training, but also that they train the mind to handle uncertainty long enough so that they can nudge their responses in the right direction. In ultra running in particular, an athlete must learn to create space when things don’t go to plan, so they don’t jump straight from unease to the quickest possible solution, but rather to the ‘correct’ one.

(15). What did your strength training comprise of today? Even in the longest endurance events, strength is a key factor in successful competitive performance. The weight room is a foreign land for many distance runners, so it’s important athletes learn to give detailed objective AND subjective feedback if lifting weights for the first time. Classic weight training has its obvious merits, but there are many other ways to improve the strength: hill sprints, multi-jumps, medicine balls, and body weight circuits. Each modality has it’s own language that needs to be learned. Also, post-resistance training protein intake deserves a mention!

(16). At what stage are you at in the menstrual cycle? How do you feel at different times of the month? In particular, what the coach is looking for are fluctuations in energy levels and mood (along with any other symptoms) in order to try to find a connection between the athlete’s cycle and training output. Menstrual cycle tracking may help identify when during the cycle certain types of training might lead to the most positive training adaptations. For example, it has been suggested as beneficial to adaptation to perform strength training during the later follicular phase where oestradiol predominates and more endurance training during the luteal phase of the cycle where progesterone is the dominant ovarian hormone. And contrary to popular belief, of the four main phases of the cycle, it is often during menstruation that women are more likely to feel at their ‘strongest’. Also, and most importantly perhaps, regular menstruation acts as barometer of internal hormone health. So a good coach should be also looking for any abnormalities in the cycle as this may be a clinical sign of RED-S.


Why We Dont Use TrainingPeaks at VO2maxCoaching.


Sources and Recommended Reading:

Koop (2023),

Nicholas Tiller, et al. (2022). Baseless Claims and Pseudoscience in Health and Wellness: A Call to Action for the Sports, Exercise, and Nutrition Science Community.

Diego Jaén-Carrillo, et al. (2020). Mechanical Power in Endurance Running: A Scoping Review on Sensors for Power Output Estimation during Running.

Rachel Aubry, et al. (2018). An Assessment of Running Power as a Training Metric for Elite and Recreational Runners.

Rodger Kram. (2000). Muscular force or work: what determines the metabolic energy cost of running.

Peter Düking, et al. (2021). Monitoring and adapting endurance training on the basis of heart rate variability monitored by wearable technologies: A systematic review with meta-analysis.

James Navalta, et al. (2023). Heart rate processing algorithms and exercise duration on reliability and validity decisions in biceps-worn Polar Verity Sense and OH1 wearables.

Bryson Carrier, et al. (2020). Validity and Reliability of Physiological Data in Applied Settings Measured by Wearable Technology: A Rapid Systematic Review.

Anna Saw, et al. (2015). Monitoring the athlete training response: subjective self-reported measures trump commonly used objective measures: a systematic review.

Carl Foster, et al. (2021). 25 Years of Session Rating of Perceived Exertion: Historical Perspective and Development.

Lawrence Armstrong, et al. (2021). Overtraining Syndrome as a Complex Systems Phenomenon.

Jacopo Vitale, er al. (2019). HRV in sport performance: Do time of day and chronotype play a role.

Veronique Billat, et al. (2001). Physical and training characteristics of top-class marathon runners.

Hayley Young, et al. (2018). Heart-rate variability: a biomarker to study the influence of nutrition on physiological and psychological health?

Yann Le Meur, et al. (2013). Evidence of Parasympathetic Hyperactivity in Functionally Overreached Athletes.

Daniel Plews, et al. (2015). Heart-Rate Variability and Training-Intensity Distribution in Elite Rowers.

Samuele Marcora, et al. (2009). Mental Fatigue Impairs Physical Performance In Humans.

Joanne Mallinson, et al. (2023}. Protein dose requirements to maximize skeletal muscle protein synthesis after repeated bouts of resistance exercise in young trained women.

Nicky Keay, (2022). Hormones, health and human potential.

Glenn McConell, (2022). Exercise Metabolism.

Max Saller, et al. (2023). A Review of Biomechanical and Physiological Effects of Using Poles in Sports.

Trent Stellingwerff, (2021). Overtraining Syndrome and Relative Energy Deficiency in Sport: Shared Pathways, Symptoms and Complexities.

Tanja Oosthuyse, et al. (2022). Understanding the female athlete: molecular mechanisms underpinning menstrual phase differences in exercise metabolism.

Jose Areta, et al. (2022). Nutrition for female athletes: What we know, what we don’t know, and why.

Ronan Doherty, et al, (2021). The sleep and recovery practices of athletes.

Sarah Blackstone, (2020). Fitness Wearables and Exercise Dependence in College Women: Considerations for University Health Education Specialists.

Gerhard Blasche, et al. (2016). Task-related increases in fatigue predict recovery time after academic stress.

Patrick Wilson, (2021). Sport Supplements and the Athlete’s Gut: A Review.