Distance Training by the Numbers

Specificity is an understated principle in proper endurance training. Specificity means that adaptations to training are specific to the intensities the body is subjected to. Lots of long slow distance running will make a great long slow distance runner. Lots of fast running maketh the cheetah but not necessarily the antelope!

Distance training for long distance runners need specific intensity application and repeated application over the course of weeks and months, maybe years. All intensities are important in specific proportions but endurance and tempo is where most of the time is spent building the body of the endurance runner.

The steps below outline the way to locate and identify specific training areas, assuming the runner is mostly training in flat areas without the complexities of mountainous terrain.

QUICK SHORT VERSION

Critical speed (CS) is roughly a runner’s 30 minute mean-maximal running speed or alternatively pace. Running above CS forces the runner to tap into a battery store inside the body that discharges very quickly until eventual exhaustion. This is all you have to know to continue below.

Step 1 : Establish your 5K best time. Locate your current best 5 km time in Table 1. “Current” means a performance within a 42-day window and in weather conditions similar to present. 5K timings are given in discrete increments for ease of use. Round up or down to the nearest 30 seconds but using proper judgement.

Step 2: Read off the 1000m pace from the same row. This is the “min/km” pace familiar to us on a watch. Moving to the left or right of that number, find corresponding splits for 400m through to 1600m when running at the same pace. Use these split timings to run track based sessions.

Application Example : A track session comprises of 6 sets of 800m at CS. For a 20-minute 5K runner, referring to the Table 1, this corresponds to approximately 3:18 per 800m. To fine tune their pacing at the 800, they can try and hit 1:39 per 400m which is also provided in the chart.

Step 4 : Use Table 2 to identify training paces which is applicable to both track and outdoor runs. The floor identifies the pace not to fall below and the ceiling for the pace not to exceed. The critical pace is also provided in the table to compare the margin between your chosen run pace and critical pace.

Application Example : A runner is told to do 10km run at their endurance zone. For the 20-minute 5K runner, the pace window falls within a band of 5:26-4:52 min/km. To spice things up for race specificity, the runner may negative split the run, going out 5K at 5:20 min/km and coming back at 5:00 min/km.

Step 5 : With time, evidence may start to pour in that a runner’s 5K time has improved. Establish the new 5K time and the training zones using the same tables.

TABLE 1 : 5K ability based training splits at critical pace. Use the numbers in a particular row for track based interval training.

Table 2 : Guidelines for 5 training zones for distance runners. Levels correspond to an arbitrary classification method I use, to group runners by VDOT. For example, all level 3 runners have VDOT in the 30’s, level 4 have VDOTs in the 40’s.

LONGER VERSION FOR BETTER UNDERSTANDING

Critical pace marks a fuzzy nevertheless well documented demarcation between stable and unstable physiology. The physiology bordering the intensity band around critical pace is distinctly different.

At faster than critical pace, endurance time is limited as metabolites and waste products build up in the cells and lead the runner to an unstable state that is non-sustainable. Running at intensities close to critical pace targets exclusively carbohydrate dependent muscle fibers such as Type IIA and Type IIX.

Running at lower-than-critical intensities results in a stable physiology where the body maintains an equilibrium that allows one to run longer distances. This is the sustainable region.

Critical pace can be roughly obtained by taking the slope of the line drawn on a distance-time plot with 3-datapoints – the runner’s best 1600m, 3200m and 5K timings.

Generally, I have found critical pace can be sustained for around 25-30 minutes. This aligns with the research from sports such as running and cycling and from understanding other coaches’ practice, such as that of Dr. Tom Schwartz.

You can read a more detailed scientific background behind critical speed on my blog : http://www.georgeron.com/2020/04/Critical-Power-Concept.html

I have also found critical velocity (CV, min/km converted to kph) to be roughly 85% of VO2max, which is an athlete’s aerobic ceiling. Well trained runners race distances from 1600-3000m at 95-100% VO2max but 5K and longer are done at lower speeds.

Suppose in a VO2max laboratory test, a recreational runner maxes out at their VO2max at a treadmill speed of 18 KPH. 85% of 18 KPH = 15 KPH or 4:00 min/km. They are very likely to find that this is the pace sustainable for 30 minutes and slightly below what they could sustain as a 5K race pace.

The running zones in Table 2 are designed to the original specifications of Dr. Philip Skiba in his scientific work in this area.

To be a bit conservative in the paces, I’ve used the “division” method to arrive at percentages of a given pace. The division method yields slightly slower paces than multiplication method, particularly for those runners who are on the slower end of the 5K spectrum. (This method might be useful for running in hot, humid weather because finding percentages of pace by division leads to numbers that are linear increases in speed with % changes in pace. Thus, with ramp up in pace like 100, 105, 110% of CS, the effort required wont be as aggressive as it would in the multiplication method).

The zone are as follows :

Zone 2 Endurance : 124-115% critical speed. This is where the meat of long distance training is done and a much used area for marathon pacing.

Zone 3 Tempo : 114-105% critical speed. This is next level up demanding a more focused attention for 1-2 hours. The upper end of tempo lines up well with the half marathon pace for a 1:30:00 half marathoner.

Zone 4 Threshold : 104-95% critical speed. The floor of threshold band is basic for 10k race pace while the upper end encroaches into 5K race pace. This is the area in which critical pace falls.

Zone 5 VO2max : 94-84% critical speed. Faster than critical pace. Time of run is unsustainable and may only last for 6-12 minutes.

Zone 6 Anaerobic/Neuromuscular : <84% critical speed. This is exclusively the zone for sprint based HIIT training and practicing strides. Most of the running here is done according to feel and not by watch.

Note : Zone 1 pace is for very easy runs and recovery. Like for Zone 6, running here is done according to feel and not by watch. It is not provided at all on the tables and is left to the independence of the runner to establish.

The research that has led to the discovery of specific adaptations in the body within each of these zones are out of the scope of this article because that is the domain of sports science literature. You can find a more detailed treatment on this in Section IX of article : http://www.georgeron.com/2020/04/Critical-Power-Concept.html

However, for this article, I can summarize following :

Zone 2 Endurance training can lead to : Increased muscle capillarization (when you hear “capillary runs” from me, that means endurance run!)

Zone 3 Tempo training can lead to : Improvement in critical pace, improved economy, Type IIX to Type IIA muscle conversion

Zone 4 Threshold training can lead to : Improvement in VO2max, glycogen storage and use and critical pace

Zone 5 VO2max training can lead to : Many of the above suggested adaptations. In addition, increased size of Type I/II muscle fibers and oxidative enzymes.

Zone 6 Anaerobic/Neuromuscular training can lead to : Fiber shifts from Type I to IIX muscle fibers, improved muscle creatine phosphate, increased peak running power output. A minimal amount of improvement in VO2max.

The recipe that goes into the training of a long distance runner is very specific to that runner. That recipe is delivered through a relationship between coach and runner and it cannot be given in a cookie cutter style. So, the profession of run coaching is a very technical one.

Being in a performance club like House of Runners allows the runner to taste different recipes and apply the training zones in a group style format, training with other runners who are either in the same , or neighboring fitness brackets. A lot of the understanding gained is highly dependent on how willing, curious and serious the runner is.

-Ronnie

APPENDIX : DATA FROM CLUB SESSIONS

This INSTAGRAM video shows the reel highlights from a 10K time trial on neighborhood roads. Runners would have had to run at Zone 4 Threshold to establish reasonably accurate reflection of 10K capability.