I have set myself the ambitious target of setting the clock back six years by bettering my M60 half-marathon best time, achieved in 2007. The intervening 6 years have brought a series of minor illnesses that have disrupted training. The most recent disruption was an episode of arthritis in the early months of this year that finally resolved in March leaving me with reduced aerobic capacity and seriously impaired endurance. I had a total of 27 weeks to my target race at the end of September, to re-build my aerobic base and develop the speed-endurance that is the cardinal requirement for a half-marathon. For a younger person, 27 weeks would generally be ample time to achieve this, but one of the major problems of being elderly is a reduced capacity to tolerate hard training. Furthermore, the fragile state of my joints dictated that at least in the early stages, it would be necessary to do a substantial proportion of the rebuilding of aerobic capacity on the elliptical cross trainer
Over-view of the plan
As reported in my recent post, I devoted 10 weeks to rebuilding my aerobic base. All of the running was at easy paces. In addition I did a weekly aerobic interval session on the elliptical cross trainer, designed to include a brief period near lactate threshold within each interval to begin developing the capacity to metabolise lactate. Over the 10 weeks I achieved my goal of building up to a weekly training volume of 50 miles including the elliptical session (taking 100Kcal of energy consumption to be equivalent to a mile of running), but was a little disappointed that my legs could only cope with about 30 miles/week of actual running. I achieved a 5% improvement in aerobic capacity over the 10 weeks, which compares favourably with what a younger runner might expect to achieve from 500 miles of easy paced running. However it was far short of the aerobic capacity required to achieve my HM target. I managed to do 12 longish runs (greater than 15Km) but found that I even at a slow pace, these long runs left me exhausted. Ideally I needed a longer period of base-building, but I could no longer ignore the need to begin developing the speed-endurance required to maintain a pace at the upper limit of the aerobic zone for 21 Km. So at the beginning of June I moved from general base-building to race specific training.
I decided to divide the remaining 17 weeks into three blocks:
1) Seven weeks of transition in which I worked separately on developing speed (repeated short burst at race pace and a little faster) and endurance (weekly long slow runs of 15-20 Km);
2) Eight weeks in which the main focus would be on the speed- endurance required to maintain race pace for a substantial distance
3) Two weeks of sharpening/tapering with the focus on maintain speed while allowing full recovery.
I have now completed the 7 week transition period. With the introduction of some higher quality sessions, I have cut back total training volume from 50 to 45 miles (equivalent) per week. In light of the need to condition my legs to the demands of running a HM. I have reduced the proportion of the training on the elliptical for 45 to 30 percent, so despite the decrease in total volume I have actually increased the average number of miles run from 28 to 32 miles per week.
Sessions in the transition phase
Each week I performed one moderately intense running session. The moderately intense sessions included downhill stride repetitions; long uphill repetitions; 20x250m intervals at 5K pace; and 4x1Km intervals at 5K pace. I continued to do a weekly aerobic interval session on the elliptical cross trainer as during the base-building period, together with a weekly long run of 15-20Km. In addition, I introduced progressive runs, initially of 8-10Km, in which I aimed to increase pace to a pace near to planned HM pace in the final Km.
As reported in my post on 17th July describing the running version of the sub-maximal test, there was a substantial improvement in my fitness over the middle weeks of the 7 week block. Heart beats per Km decreased from 726 to 678 at a moderate effort (88% HRmax). In the second week of the block, I did a 4x1Km interval session at 5K pace (4:38 min/Km). Beats/Km averaged across repetitions over the final 30 sec during which HR was stable at 96% max, was 683 b/Km. This matches the estimate of 690 beats/km calculated from the sub-maximal test at around the same time, after correcting for the anticipated decrease in b/Km at 96% HR max compared with 88% HR max.
At the end of the block, I repeated the 4x1Km session at a virtually identical effort level. Beats/Km averaged across the final 30secs of each repetition had improved only trivially from 683 to 675 b/Km. However ambient temperature was 26 deg C compared with 16 deg C during the previous interval session. During the warm up, my heart rate had been about 5% higher than anticipated, so even a conservative estimate suggests that at a more moderate ambient temperature, b/Km at 5 K pace would be around 660 b/Km, consistent with the prediction from the most recent sub-maximal test. So overall, it appears that my aerobic fitness increased by around 7% during the 7 week block This compares favourably with the increase of 5% during the 10 week base-building block and is consistent with the expectation that aerobic fitness increases more rapidly during higher intensity training.
In the next block of training, the major goal will be increasing speed-endurance: that is, the ability to maintain race pace at the end of a long run. As a preparation for the next phase, in the final week of the transition block, I made the long run gently progressive. I managed to sustain a pace of 5:20 min/Km with a moderate subjective effort of 13/20 for the final Km of a 19 Km run. In light of the serious loss of endurance that I had suffered following the period of arthritis, this was an encouraging beginning of the campaign to introduce HM pace running into long runs. During the next block of training, the key runs will be long runs progressing to target HM pace (4:44 min/Km) for the final few Km. However, despite the encouraging evidence as I move into the second block of race specific training, the target remains daunting.