The Lake Loop

balancing Fitness, Fatigue and Form

Author Vince Paikowski, a former NCAA division one runner is an Evoke Endurance coach, father, husband US Army Captain 2021 Best Ranger Competition winner, former Army Ranger . He’s run a 2:27 marathon, 50 miles in 6:16 and a 14:17 5km and holds the FKT on the John Dick Memorial 50km course.

Every week, on Monday, I begin my week with an eight-mile loop. Especially after a summer of racing – using the fall to get back into a base period and develop predictable and consistent training is important. If you’re like me, you probably have a predictable “go-to” loop as well. I call mine Lake Loop. This eight-mile loop is relatively flat and curls around a quiet lakeside neighborhood. It has a small, crushed gravel strip which runs alongside the asphalt road and cuts between the houses and the lakefront. Trees line both sides shuttering the wind, and on most Mondays, I can complete the loop before anyone around the lake has woken up. It’s peace. For me, Lake Loop is a great way to begin a week as a sort of diagnostic exercise.

I try to manage training through the relationship shared between three variables, Fitness, Form and Fatigue. Fitness is as it sounds, it is your absolute capability physically. However, Fatigue doesn’t always allow us to access that fitness. Therefore, fatigue is a reduction in our capability caused by training stress. Once fitness is reduced by fatigue we are left with Form. Form is what you are able to access on a given day.

These three variables are inextricably linked. Simply put: Fitness = Form + Fatigue. If you think of your fitness as 100% of what your capable of, your form at any time will be less than that if you’re training and considerably less if carrying significant fatigue. That’s because fatigue reduces accessible fitness – I am sure you have felt an easy run before which feels remarkably – less easy. 

An easy allegory for this is to think of it in terms of a Marathon morning. The morning you wake up in peak race condition and step to the line you discover what your fitness is. It is the level to which you can complete the 26.2 mile distance. You cross the line and finish with a big PR. Could you do it again? Of course not, because fatigue would not allow you to. You aren’t less fit. Instead your form has been degraded – and degraded so much that you would likely not even be able to run another mile at the pace you just had for 26.2 moments before.

This example is easy to picture in this context but becomes more nuanced when we think about the relationship between form and fatigue in routine training. Fatigue is a requirement to drive physiological change. If you want to get more fit, you need to accept fatigue as a familiar friend. However, fatigue is cumulative – that is, it will continue to build in intensity if you never allow your body to recover. Let it build too much, and you will never maximize the form necessary during key workouts and races to perform well. This is where a day of diagnostic exercise can really assist in an athlete and coaches ability to identify what is happening within their training.

After my last 100 miler in August, I took time to recover. When I started running again in September, I religiously monitored my Monday Lake Loop. It was a Zone 2 run with the goal of keeping the average heart rate between 140-150 and the relative perceived exertion low. From September to December, I was committed to rebuilding my base – but like many athletes I sometimes out chase my own fitness. The Lake Loop kept me honest. Below you can see the average time for the Lake Loop across an 18-week base phase of training. 

Across the 18-weeks of base building I realized a 4% decrease in the amount of time it took to cover the 8-mile loop. But time only tells part of the story, what was more interesting was how it paired to the Average Heart Rate seen across those sessions:

In those same 18 weeks my average heart rate for the loop dropped 3%. If you look at these two graphs together, it tells the story of Form, Fatigue and Fitness. Fitness is the Macro picture shown in the Time Improvement graph. It is a general increase in capability. Form is the micro view – notice the increase in time it took on 21 October, 25 November and on 30 December. Notice how this correlates directly with increases in HR Averages on the same dates. Interestingly enough and not surprisingly they also correlate as coming directly after peaks in my mileage during my base phase. 

Overtime the results are clear, my body is becoming more efficient by doing the same amount of work, while costing my body less in terms of energy. Or at its core my fitness is increasing, but it is not a linear path. Expecting linear improvement in training is not realistic because of fatigue’s role in the development of fitness. This is where managing volume, intensity and therefore fatigue on a predictable training cycle becomes critical. Taking deliberate recovery weeks minimizes the likelihood of accumulating excessive fatigue and allows us to continue training at a form which will assist in the one real goal of training: performance improvement. 

Conversely the above is evidence that feeling laborious one day or moving through a diagnostic route slower does not mean that your fitness may be decreasing. Instead, it is important for athletes to view these blips as decreases in form, caused by increases in fatigue and if paired with an increase in relative perceived exertion should be met by consequent blocks of recovery. 

 Train at high form, develop fatigue, once form drops, recover – repeat. This is the cycle that drives improvement. Too often athletes train through high levels of fatigue, unable to hit the paces or efforts required to meet their goals whether on the trails or the roads. Don’t sacrifice high quality training chasing unnecessary fatigue. Instead manage fatigue to train at a form which promotes fitness – and add a Lake Loop into your week to keep track of where you’re at.