Understanding Training Peaks

Understanding Your Training Peaks Numbers 

Training Peaks is a powerful training tool for the endurance athlete. To help you make the most of its features here is an article on how to use some of its metrics. These metrics are best combined and displayed within Training Peaks standout feature, the Performance Management Chart (PMC). There are three key markers expressed in the PMC. These markers are the Acute Training Load (ATL), Chronic Training Load (CTL) and the Training Stress Balance (TSB).

Training Stress, Intensity and Fitness

ATL, CTL, and TSB allow us to take both a view into the past of the athlete, a current view of fitness, as well as project into the future when using the PMC. This all goes back to the root metric of Training Stress Score (TSS) which scores a workout based on duration and intensity as a factor of your threshold pace, heart rate or power. 

Chronic Training Load (CTL) or “Fitness”

Think of Chronic Training Load as a measure of your true fitness. It is an ongoing average of your daily training (TSS) specifically looking at the last six weeks or 42 days. This shows your long-term training load and gives a trend line of where an athlete is going. A positive (upward) trending line shows an increasing training load and decreasing (downward line) shows a decreasing level of training load. 

Steady progression is key to prevent injuries, large spikes in CTL correlate with a large amount of training stress. Very fit or experienced athletes can increase their CTL quickly whereas new or older athletes may need to ramp up their training more gradually. Large amounts of training load must pair with adequate recovery to avoid injury, illness, burnout etc. 

CTL and TSS are related and you can use the scale below to determine the intensity of a workout with respect to your current fitness. In this example, we’ll assume the athlete has a CTL of 50.

Hard Workout: A hard workout will result in a TSS score that is 50%-100% above your current CTL (TSS for a hard workout would be 75 – 100 TSS).

Moderate Workout: A moderate workout will result in a TSS score that is 25% above your current CTL (TSS for a moderate workout would be 60-70 TSS).

Easy Workout: An easy workout will result in a TSS score that is 10-25% below your current CTL (TSS for an easy workout would be 35-40 TSS).

From the above you can see that an athlete with lots of time to train can (and should) accumulate much of their TSS through moderate and easy workouts. Those with less time would need some more high intensity training to accumulate more TSS. The mix of intensity of course depends on the athletes stage in their training and their goals.  

Acute Training Load (ATL) or “Fatigue”

Acute Training Load looks at how your most recent training impacts your body. ATL calculates a rolling average of your workout TSS over the last seven days. There is a correlation between fatigue and fitness scores, when your fatigue score is less than your current fitness score, you will normally see a positive Training Stress Balance (TSB) value. However, if you are deep into training you will see a TSB score that is greater than your CTL score.

Steep inclines indicate large loads and will result in a significant and resultant inverse TSB. If you are doing lots of high TSS workouts, you can expect high ATL scores. You can bring down high ATL scores by doing recovery (low TSS) workouts in addition to rest days.

Training Stress Balance (TSB) or “Freshness”

Training Stress Balance is the “ready to race” metric where the more negative the number, the more layers of fatigue an athlete has accumulated and the more positive the number the more recovered and ready to perform an athlete is. This metric has a couple of rough rules that can help guide athletes. However, everyone is different and athletes should rely on their past experiences and recent performances to determine how recovered they need to be to perform well.

  • An ideal TSB range for a peak performance falls between +15 and +25. While zero indicates the athlete has reached a training equilibrium, complete recovery is often needed for peak performance, especially for long-distance racing.
  • The ideal training zone for TSB falls between -10 and -30. It is thought that if athletes push beyond -30 for more than 10 days they are headed for extreme strain. Numbers extending beyond -30 will require consecutive days of rest to achieve the necessary recovery for future performance. For example this is something you might achieve at a training camp, which would then require a recovery week to absorb the hard week of training. 
  • The opposite is true as well, if you start to see +15 to +25 TSB you are extensively recovered and essentially losing fitness.

The PMC is only as good as its data. 

Reliable data creates a clear picture of an athletes fitness. Incorrect zones will undercut any planning and projecting. Propery managed data allows you to maximize the effectiveness and density of your workouts. It is imperative to set your training zones correctly before you can have any confidence in the information being produced. It takes 42 days to get concrete CTL when starting fresh. 

Not all TSS is created equal. 

TSS is the crux of the performance management chart but it is worth noting that it has its flaws. Here is a few examples of how training sessions with the same TSS score would actually feel very different to the athlete: 

A session with intervals of 4 x 10 minutes at a given intensity would feel very different (maybe even impossible) to a session of 1 x 40 minutes at the same intensity. Yet these would both have the same TSS. 

A flat road run at say 5 minutes per KM pace would feel very different to a lumpy trail run at the same pace, again they would have the same TSS. 

A 60 minute continuous swim in a cold choppy sea and a 60 minute continuous swim in a heated pool, both at the same pace giving the same TSS, again would feel very different to the athlete. 

enduraprep plans training

Enduraprep athlete Scott at the Moab 240 Ultra Marathon.

On 15th October 2019, Scott, a Welsh ultra endurance athlete from Penarth, became the first Welsh person to complete one of the world’s longest and toughest ultra marathons, The Moab 240, a 244 mile non-stop footrace around the deserts and mountains of Utah, USA.

Despite toeing the line with some incredible ultra running athletes such as David GogginsCatra Corbett and Michael McKnight, Scott finished 35th out of 121 starters. 94 runners finished, with Scott completing it in 93 hours 58 minutes, only sleeping for 3 hours during the entire race.

The Moab 240 is a 244 mile run where 121 competitors line up at the 3,000ft start line to scale over 29,000ft of vertical climb and the same descent non stop over the course of several days. The terrain is difficult – large parts are difficult to run due to large boulders, cliff edges and loose rock, coupled with huge inclines.

The spectacular scenery and running settings vary from tree lined mountain sum-mits at just over 10,000ft to barren canyon land desert around 3,000ft. You would be forgiven for at times thinking you’re in a movie scene, then the next minute you feel transported to an alpine retreat. Both of which were scenarios that Scott actually hallucinated on the run, as he discusses below.

The course itself is a full circumnavigation of the Moab desert in Utah, which sees runners tackle and conquer two mountains ranges (Shay mountain and the La Sal Mountain ranges).

This year had an added challenge due to the cold front that was effecting much of America, seeing temperatures range from mid 30 degrees in the day through to -8 degrees in the evenings, coupled with 12 hours of darkness meaning all runners had to carry full kit all the time. This course is not for the faint-hearted nor for the novices, evidenced by strong elite runners DNFing such as Ex Navy Seal, David Goggins. This is testament to the gruelling nature of the course!

The race itself is organised by Candice Burt whose tagline is “200’s are the new 100’s”, which really does highlight this growing shift in the population to try and push themselves further and harder. The 200s are growing in popularity but are still relatively new in the world of ultra running, with Candice Burt really being the main pioneer of 200milers in the US. Her race organisation is exceptional with every runner having spot trackers, medical ATVs due to the remote nature of the course, some of the best photographers in the business (Scott Rokis, Hilary-Ann and Howie Stern) and fully stocked aid stations serving everything from burgers to quesadillas, which also have sleep stations.

To put into perspective just how hard this race is, more people have climbed Everest (4000 people) than completed one of her 200 mile events (circa 300-400), which is impressive in itself. Scott is the second British person to compete and finish and the first Welshman to do so.

Scott Jenkins Moab 240
Some of the spectacular route

So what drove Scott to apply for such a gruelling race and what actual toll does it take on ones body to complete such a feat of endurance.

“For me, I genuinely believe that we each have a responsibility to help and support others where we can. Whether that be listening and helping a friend through to raising money for charity. For me, over the years, I’ve found the way I am able to have the most impact is by pushing my body to extreme in order to raise money for charity. My brother Rhys and I, have found that the harder we push our bodies, the more people are willing to donate money to charities we care about and support. For me, that charity is Operation Smile, which I’m an ambassador for. It’s a charity that repairs children’s cleft lips and pallets so they can smile for the first time – it’s a pretty cool charity to be involved with to be fair”

Pushing the human body is not new to Scott. He’s already got an impressive resume from running 2,000 miles from Boston to Austin back in 2010, he’s cycled point to point from Seattle to Jacksonville in the States in a 4 man non-stop relay and unofficially ran the Badwater ultra marathon course twice. Scott this year also took part in Britain’s three longest, non-stop, point-to-point towpath running races: the Grand Union Canal Race (145 miles from Birmingham to London), Kennet & Avon Canal Race (145 miles from Bristol to London) and the Leeds & Liverpool Canal Race (130 miles from Liverpool to London), completing the illustrious ‘Canal Slam’ finishing 6th. He used them as training runs for the Moab 240 so his coach, Lawrence Cronk of Enduraprep, could try to improve his plan and build a race plan fitting for Scott’s running progression to see him finish and maximise his finish position at Moab 240.

“Running for me is a passion – but that doesn’t mean it’s easy for me either – yet Lawrence has made huge improvements in my running technique and speed through using VO2 max testing and training in heart rate zones, which was completely new to me this year. I’ll never be the fastest runner but I’ll always try to complete what I set out to do. For me, Moab was no different but the toll it took on me in the final 10miles of the race was like nothing I had ever experienced. Sleep deprivation was something I’ve experienced in other races, however, what I experienced at Moab was more like a parallel universe/alternative state – like nothing I’d ever experienced before. It sounds weird but at one point I called my wife, who was also crewing me and asked her what she had been doing for the last week. When she replied with crewing you in the race, I asked what race. I had no idea where I was and what I was doing. I couldn’t distinguish between reality and make believe. It was like my mind was completely disassociated from my body. I was hallucinating cowboys sitting on rocks watching us through to me having a lighter and trying to make a fire to keep warm. It didn’t wear off until two days post event. I felt I was in the Truman show”.

Scott Jenkins Moab 240
Scott and his super crew

His wife, Abby, who ran the last 16.5 miles with him added, “It was hell on earth that last section. He was delirious. He went from being loving and empathetic to disoriented and delusional in split seconds. It got to a point where his body was moving fine but his mind kept telling him to sleep and that he had fin-ished the race. He just kept saying I need to sleep and would curl up on cliff edges. I eventually got him to move to lay under a rock for more warmth but he couldn’t sleep because we had over-caffeinated him to get him to the end. We gave him coke, coffee, 2 x 5 hour energy shots and god knows how many caffeinated gels in that last stretch alone coupled with nuun and salt tabs to try and rebalance lost electrolytes and salt. It got to a point his body wanted to sleep but the caffeine fought it and it created a limbo state for him. Thankfully another runner, Jason Wooden talked sense into Scott and got him to move again and finish the race. Only another runner could have talked sense into him as he was completely gone. To put it into perspective just how gone his mind was, we thought as a crew, based on Scott’s pace, he would finish 7pm on 14th October and continue to finish in the Top 20 where he had been most of the race, and in fact he finished at around 5am on 15th October – the sleep deprivation in those last 10 miles added 10 hours to his expected finish time showing you just how difficult it was for his mind to comprehend he was still in a race and to move his body forward. It was more mentally and emotionally draining than physical at this point and that was hard to see yet somehow from somewhere, he managed to connected the two – very loosely, and power through to the end. His strong pace throughout the race still saw him finish in the top 25% despite this setback in the last 10 miles.”

Scott Jenkins Moab 240
Scott finally makes the finish

“For me, everyone thinks running is a solo sport, which couldn’t be further from the truth. I often liken it to Tour de France, where one cyclist has a whole team competing on his behalf. For me, that is no different in ultra running. My crew, Jake Cooper (from Reno, Nevada) and Rhyd Morgan (from Penarth also) were unbelievable. They ran over 65 miles each with me, pushing me, popping my blisters and putting up with my diva requests and weird hallucinations. They were beyond unbelievable and this finish is as much theirs as it is mine as without each of them and Abby, I genuinely believe I could not have finished this race. It’s by far the hardest race I’ve ever done and one of my proudest and most memorable experiences to date. I just hope it either inspires someone else to go for a run or to donate to Operation Smile as so far we’ve raised enough money for 14 children to be able to smile for the first time. It would be cool if we could help 20 kids as I like round numbers”

So what’s next for Scott? “Eating lots. I’ll also watch as my toe nails progressively fall off and sleep, sleep lots. However, I’m already thinking what’s my ‘A’ goal for Operation Smile next year as I need a goal to work towards and motivate myself. I do firmly have my sights on Badwater next year and pray I get selected to compete as this has been a 10 year dream and would be great to compete in the race the year I turn 40. I’m also keen to create one of my own challenges again as I’ve not done that for a year or so, as well as competing in different races that I’ve yet to experience”

If you want to donate to Operation Smile go to https://uk.virginmoneygiving.com/fundraiser-display/showROFundraiserPage?pageId=1096817. Scott, along with his brother Rhys, will be talking at next year’s National Running Show on “running is not a solo sport” and can be followed on Instagram @scottjjenkins and on Facebook at www.facebook.com/thejenkobros where he documents all his running escapades with his brother Rhys. If you want to see any pictures from the race itself of all participants, go to www.run200photos.com to get a better idea of the course and amazing landscape that is The Moab 240.


Badwater 135 – 2019

At the 2019 edition of the Badwater 135 ultra marathon Rhys Jenkins became the first Welshman to complete the race. Having known and coached Rhys for a number of years now I’ve become very familiar with his passion/obsession with Death Valley so when he finally had an application accepted to take part in the race I couldn’t turn down the opportunity to crew for him and WOW what an experience it has been!

What is Badwater 135? 

Labelled ‘the world’s toughest footrace,’ It’s a 135 mile ultra marathon that starts at the Badwater Basin, below sea level and finishes on Mount Whitney. The course covers three mountain passes with around 3000 metres of elevation gain. Temperatures on the hottest parts of the course have been known to go over 50 degrees celsius! There isn’t a whole lot of relief at night either, heat radiates off the road and surrounding rocks long after the sun goes down. In a nutshell, it’s long, it’s HOT and it’s hilly!  

How did Rhys prepare? 

Firstly, you need to become eligible for a place at Badwater. You need to complete three 100 mile plus runs in 18 months, one of these needs to be from a list of events that Badwater HQ provide. There’s also an application process where you get a chance to highlight your reasons for entering and any other events/challenges or contributions to running worth noting. This is where I should mention, Rhys has actually run the Badwater course multiple times before, not being sure he would ever get accepted into the race, Rhys and brother Scott took things into their own hands.

In terms of training we didn’t look to reinvent the wheel with Rhys’ plan. Lot’s of steady state ‘Zone 2’ running with one VO2 max interval run and one session of hills reps per week. In the final 8 week block of training we made the ‘hill’ reps more like ‘mountain’ reps and added 4 sauna sessions/week. Sauna sessions grew to 60 minutes and would need to be completed straight after a run while core temperature was still elevated. While in the sauna he would do some stretching, hydrate and practice eating in the heat.    

Badwater 135 Enduraprep Endurance Coaching

The Support Crew

Every runner at Badwater needs an official crew of up to four people and their own support vehicle. 

John would be our driver, he lives in Texas and has helped Rhys on multiple endurance challenges, including those in Death Valley. His knowledge of the route and Rhys’ strengths/weaknesses at certain points along it where invaluable. He’s also a straight talking guy, excellent at laying down the facts whilst being void of emotion, a really useful trait when sleep deprivation takes hold and the brain gets foggy. 

Stuart, sports therapist, he’s looked after Rhys in the UK with taping, massage and cupping. He came armed with a theragun and he wasn’t afraid to use it! He also did a great job as quartermaster of the support car by making sure everything was stored neatly and easy to locate during the race. 

Scott, Rhys’ older brother. An extremely accomplished ultra runner himself with plenty of Death Valley experience.

Rhys would be allowed a pacer after the first 42 miles. Myself and Scott would share these duties, the plan being to switch regularly enough to stay fresh and keep the quality of our support high. 


The race, how did it go? 

There were three starting waves, 2000, 2130 and 2300 on Monday evening. Each wave had to hit 50 miles by 1000 the next day so the fastest runners started later. Rhys started at 2000, sunset. We had a plan to run guided by heart rate. Through VO2 Max tests at Enduraprep HQ and practice in training we had established that sub 150BPM was a safe intensity for Rhys to run at. If it rose above this at any point he would start power walking. There was always the risk that by mid morning the next day his heart rate would start doing funny things thanks to one night without sleep and the soaring heat. Every few miles, I’d have Rhys shout out his heart rate as he passed, we would record it so we could be dynamic with the plan. Anyhow, he seemed comfortable between 130-140BPM whenever we checked, the heat didn’t seem to be elevating his heart rate, testament to his heat acclimation work at home and his fluid intake, which was on target. In fact he was visibly gaining weight during the first 35 miles. We had possibly overdone the sodium intake causing him to hold water, maybe a little over cautious as Rhys feared a point in the course where he had suffered severe cramps twice before. Either by genius or coincidence the plan worked and he suffered no cramps this time, we had him carry one bottle instead of two and he kept up a suitable fluid intake through the night. 

Sunrise on Tuesday, epic! As the moon ducked over the mountains to the west, the sun peeped over from the east, I don’t have the creative writing prowess to do it justice, it was just bloody cool! Checkpoint one at 50 miles was midway up Townes Pass, the first mountain. Stovepipe Wells sits at the bottom at 42 miles, Rhys planned not to stop here. This was wise, it was chaos, the first proper chance for crews to get fuel and ice from a store. Having Rhys crack on while we negotiated the panicking crews and busy shop worked well. Sounds like we’ve got this nailed right? Well……between 45 miles and 72 miles the cracks started to appear! It has always been the plan to hike the climbs but this didn’t sit well with Rhys on Townes pass, he seemed defeated and getting to checkpoint one seemed to take forever. Ideally we would use the walking sections to have Rhys eat real food whilst it was easier to digest at a slower pace but we’d hit a wall with this too, we couldn’t tempt him with anything else but watermelon. ‘You can’t run 135 miles on just watermelon and electrolytes!’ Was eventually how blunt we had to be, this helped, marginally but there was still no hope of even finishing this event if he couldn’t eat something more substantial. Townes pass has a 9 mile descent into Panamint Valley. Our goal had been to run all of the descent before dropping into the hottest part of the course. Rhys ran some of it but took plenty of walking breaks and stops at the van. The crew were all getting concerned, if this easier section was going badly, how would he cope in the valley? Cue the mission cooling cape! We can’t make him eat, we can’t make him go faster but we can keep him cool. The cape had been soaking in an ice bucket, we wrapped it around him and without discussing it the crew all backed down a little and just let Rhys get on with it. Panamint Springs was just a couple of hours away with the option of hot food and shower if any of us needed it, we’d just get there and then re-asses. The crossing of Panamint Valley was pretty grim, temperatures of around 45 celsius and a hot wind that whipped our hats off a few times. Another major factor that plays tricks on you, out in the desert you really have no clue whether that feature in the distance is a mile away or ten miles away, Panamint Springs just wasn’t getting any closer. In an attempt to turn a negative into a positive I kept reminding Rhys that, ‘this is it, the iconic stretch, the one in all the Badwater photos, it’s meant to suck here, but you’re doing it, embrace it!’


We took our longest stop of the whole race in Panamint Springs, 45 minutes, we sat Rhys inside and fed him a cheeseburger, Stuart massaged his legs and we changed his socks. By the time we left that checkpoint we were four and a half hours inside that cut off and about to start the second mountain pass, Father Crowley. Most view it as the toughest climb on the course but Rhys, now revived, set off with Scott at a great pace, even running some of the nine mile climb, something I’m sure only the fastest few athletes would have tried. Things were looking up and further boosted by a great chat from John, the straight talking Texan, ‘Rhys tell us what you want to do, 36 hours is still on the cards, if that’s what you want, we can make it happen, if you want 40 hours, we can do that, if you want to take it easy you can walk backwards and finish in 48.’ Simple but highly effective, Rhys continued to run more than walk well into the night and we hit the 90 mile check point a full eight hours before the cut off. 

The second night was something I was, in a strange way, looking forward to. I knew things would get weird with confusion and possible hallucinations so this is where we would all need to dig deep, get Rhys through the night and he’ll be able to see the finish at sunrise. By about 0300 everyone was struggling to stay awake, Rhys even thought he was falling asleep while running, he suggested a twenty minute nap. I set my alarm, dropped off, then doof! As my head hits my chest the car door opens, it’s Rhys, ‘c’mon let’s go!’ He’d slept for just ten minutes! I necked half a can of Pepsi and literally had to chase him, he was off down the road. We could have easily lost a few hours to sleep right there and still finished within 48 hours but this is where Rhys’ mental strength really shone through, it was mightily impressive!


What we didn’t expect at this stage was for racers to still be so close together. Support car hazard lights lined the road for the twenty miles to Lone Pine. It was mesmerizing in the dark and you couldn’t look for too long without feeling woozy. Throughout that night we managed to run quite a lot, taking short breaks every 35-45 minutes. During one of these breaks we received some lovely encouraging video posts from CF Warriors and the young cystic fibrosis sufferers they support, we can’t thank you enough for these messages, they give morale and motivation a huge boost. We cracked on towards Lone Pine in time for breakfast, the last chance for hot food before the thirteen mile ascent to Whitney Portal. In my mind I viewed the final climb as something of a presession, then it dawned on me, if I was setting out for a thirteen mile hike today, that would still be a pretty long day, it’s not over yet! At the foot of the climb Pete Kostalnek, a previous winner passed us, turns out he was having a poor race by his standards and took some time out to sleep. Just goes to show, if it’s not your day, this course can be hell for even the very best! Teams already finished that were heading back down the mountain were cheering and offering up any left over supplies and the atmosphere in the final few hours became pretty emotional. We walked the final mile as a team with a Welsh flag draped around Rhys, job done in 40:45, incredible!    


If you have any questions regarding the event, our experience, or need advice preparing for such an event in extreme heat then feel free to drop me a message lawrence@enduraprep.co.uk