It is well accepted that intervals will facilitate the attainment of one’s highest ability in competitive running and many other timed, set distance sports (e.g. cross country skiing, swimming, cycling, etc.). Examples of the extensive literature supporting the efficacy of interval training are too numerous to list but I link here to that which is available from the Lydiard Foundation here and a Lydiard video here.
For running, such interval workouts are typically completed in a track setting, although Lydiard and others are also proponents of hill bounding as well. Hill bounding intervals will be the subject of a separate post.
Interval workouts on the track have a number of advantages including a smooth, consistent running surface, a compact loop, and the ability to accurately gauge and compare times for set distances to monitor progress and assess speed development. In addition doing standard distances (400 m, 800 m, 1600 m, etc.) is very straight forward on a track. For trail running competitors, track workouts are a staple of most training programs.
When I completed my last 1/2 mile track race in college (yes, way back then we did the mile, 1/2 mile (880 yards), 1/4 mile (440 yards), etc. and even odd distances like 660 yards during the indoor season) I told the coach that that race was the last time he would see my butt running around an artificial oval in the middle of a field*. At that time I had recently discovered trail running and much preferred the aesthetic and did not see any reason to continue with track competitions. That position on track running has held for almost 40 years- I have yet to run a lap on a track since that late spring day in 1977. This works for me and I am in no way suggesting that track workouts are less enjoyable and/or inferior. I prefer the trail, many (most) others love the track.
Since those college days I have been a highly competitive Category 1/2 road cyclist, an expert and sometimes professional mountain biker, and a competitive cross country skier. In each sport intervals have played a major role in my training plans and, due to the nature of each of these sports, the intervals have always been conducted on actual race courses or terrain similar to race courses. For instance in mountain biking I developed a few single track trail loops that provided appropriate interval stimuli for the sport, e.g. loops of steep 7-10 min race pace (L5a-L5b) uphills followed by steep 5-8 min race pace downhills and loops of more gradual 15-20 min uphills followed by full recovery downs. These loops were utilized in a structured way to develop aerobic muscle endurance, anaerobic capacity, and power. They served me well.
Having moved into ultramarathons in the past couple of years, the need for interval sessions has become clear should I wish to progress any further. The same has been true for my efforts in competitive cross country skiing and I have written about that here and, partly, here. In the second post on training plans for the current running season, interval workouts are an integrated and fundamental thread. Two interval sessions per week are included in the program plan. I debated about how to accomplish these workouts…. on a track? or…. should I hold to my 1977 proclamation and follow the rigor I used previously in road cycling, mountain biking, and cross country skiing by completing intervals on race course-like trails. I decided on the latter for numerous reasons, not the least of which was the 1977 proclamation, but also because the nearest track is 12 miles away and the school gets touchy about use from time to time. Also, I noted that Rob Krar mentioned in an interview that he regularly utilizes the Buffalo Park Loop in Flag for some of his interval workouts. This is a park that I had run in many times when I lived in Arizona so I knew exactly what he was speaking of.
I went about developing some trail loops that would accommodate both “track-like” sessions as well as hill repeat sessions. I found an almost exactly 2 mile single track trail loop around a natural meadow with about 50 m (165 feet) of vertical ascention/descention per lap- perfect for doing on-trail mile repeats, 800 m, etc. Here is an image of the Meadow Loop:
…. and here is an example of an 8 X 1/2 mile LT (L5a)- L5b (80% recovery) repeat session (also showing the 3 km cool down segment):
I also found a nice 0.7 km/70 m, 10% grade uphill with a corresponding similar downhill that makes a good compact loop for hill repeats. Here is an image of the Hill Repeat Loop:
… and here is an example of a 5 X L4-LT (L5a) uphill repeat with the downhill as 100% recovery:
These trail loops serve as the basis for my current two-a-week interval sessions where on Tuesdays I do a hill repeat workout and on Fridays I do “track-like” workouts on the meadow loop. The structure of the individual sessions vary and some additional examples can be seen in the training plans posted here. All interval sessions begin with an 8 km (5 mi) warm-up at L1-L2 and end with a 3-5 km (1.8-3 mi) cool-down at L1-L2.
This two-a-week interval protocol has worked out quite well as I can feel the endurance, strength, and power building up and I can see the times coming down. Although this is an expected result, there are other positive aspects to this on-trail interval training that have become apparent, aspects that I did not fully appreciate prior to putting the protocol into place and that are not developed in a traditional track setting. These additional positive aspects center around two very important elements in trail running:
- downhill running skill
- trail foot speed and turnover
Although I have worked hard at developing downhill running skill over the past two years, progress has been fairly glacial, with improvements in the 5-10% range over a season using “standard run” downhill sections for concentrated efforts. These improvements have provided passable speeds but not the sort of improvement that I know I am capable of. Enter on-trail intervals- what a difference!
Regular sessions on the Meadow Loop doing mile and 1/2 mile repeats at speed over single track terrain that includes some small, but real, downhills forces one to develop foot placement skills, stride skills, and associated small foot and ankle muscles that quickly lead to efficient (and fast) downhilling on trails. There is nothing like maintaining a 6-6:30 mile pace on a “semi-rocky” trail downhill to stimulate focus and skill development that is otherwise hard to push toward on a regular trail run. Particularly for a 58 year old!
Similarly, in the hill repeat sessions with, say, a 3 min LT(L5a)-L5b up with 1 min rest followed by a 3 min LT (L5a) downhill effort, one becomes viscerally aware of the needed focus to successfully navigate a downhill at that speed. There is no replacement for necessity to inculcate effective skill and fine movement muscle development.
I have found that the incremental skill and focus development during the interval sessions is much greater than that which I was able to attain in attempting to develop these elements on a regular distance run, independent of whether the run was a “standard run” or a “long run” effort. In the 7 weeks (14 sessions) that I have been including the on-trail interval sessions in my training plan, I have experienced a 25% increase in speed on typical 6-10% smooth downhill grades and a 35% increase in speed on typical 8-20% technical downhill grades in training. The intervals have had a remarkable impact on downhilling speed.
As far as foot speed and turnover, a similar effect is readily apparent in development of speed on flats and gradual up and downs. My rolling terrain mile times have come down by 15% at L2 and 20% at L3 since I started the interval session protocol. Whilst some of this speed is due to the enhanced, running-specific, aerobic and anaerobic cardio development, the level of comfort I have attained from a musculo-skeletal and skill perspective seems to be dominating. I say this because I come into the running season directly from the competitive cross country skiing season where my aerobic and anaerobic capacities have been highly developed by similar skiing intervals. So, although there is some additional running-specific cardio capacity development in the running intervals, the element that is new is running fast on trails and the collateral skill and muscle development. Perhaps I am an exception as it concerns the rate of improvement by including on-trail intervals in my training program, but if my past experience in training protocol is any indicator, then such will likely be the case for others.
Although it is clear that track workouts are an effective way for trail runners to develop speed and enhance aerobic and anaerobic capacities, it is also apparent that similar, on-trail, “track” and hill repeat workouts offer additional skill and small foot and ankle muscle development that is otherwise hard to stimulate in everyday training. I heartily recommend that you give some on-trail intervals a try as it might be what you need to accelerate your progress just as it has for me.
*Apparently the great Lasse Viren felt the same way as this quote from a nice article on Finnish “sisu” by Adam Chase indicates:
“Viren says he didn’t much care for running on the track outside of competition. Most of his training took place on forest trails, he says, where he’d do speed work and push the hills.”