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Keep the intervals, cut the volume: how to taper for a race

I race 100 km, and for years the last two weeks of a build were the part I improvised. Shorten the long run, sleep more, hope. Laurent Bosquet's group screened 182 studies covering that window and pooled the 27 that measured performance, and what came out is specific enough to write into a plan: two weeks, volume down by about half, the hard sessions untouched 1.

What the research shows.

In Bosquet's meta-analysis, the strongest results came from a taper of 2 weeks (overall effect 0.59 ± 0.33) in which training volume fell exponentially by 41 to 60% (overall effect 0.72 ± 0.36), while holding training intensity steady carried an effect of its own (0.33 ± 0.14) 1. A 2023 meta-analysis of 14 studies by Wang and colleagues landed on the same window, 41 to 60% less volume with intensity and frequency maintained, and measured both sides of the fatigue scale: time-trial performance improved (SMD -0.45) and time to exhaustion improved more (SMD 1.28) 2.

Neither VO2max nor movement economy budged in that pooling 2, which puts the gain somewhere below the level of aerobic capacity. Nicholas Luden's group went looking for it in the calf muscle, following 7 collegiate distance runners through a 3-week taper. Their 8 km race times improved 3%, type IIa fiber diameter grew 7%, peak fiber force 11% and absolute power 9%, with aerobic fitness flat throughout 3.

The cleanest test of what to cut is 34 years old. Brian Shepley gave 9 male middle-distance runners all three versions of a 7-day taper, each separated by 4 weeks of normal training: high intensity with volume slashed, low intensity at moderate volume, and rest alone 4. Treadmill run time to fatigue at 1500 m pace rose 22% after the high-intensity taper and 6% after the low-intensity one. The rest week produced no gain. Total blood volume and red cell volume climbed after the high-intensity week and dropped after the rest week 4.

Recreational data agrees at a scale no laboratory reaches. Barry Smyth and Aonghus Lawlor mined the training logs of more than 158,000 marathon runners and sorted them by taper shape 5. A strict 3-week taper, meaning volume that falls in each of the 3 weeks, was worth a median 5 minutes 32 seconds (2.6%) against a minimal taper. 64% of the runners in that set ran a looser version 5.

Iñigo Mujika and Sabino Padilla put the typical gain across the literature at around 3%, with a usual range of 0.5 to 6.0% 6. On a 3:30 marathon, 3% comes to 6 minutes 18 seconds.

Rest is the wrong lever.

Shepley's rest-only week is the finding runners skip, and it repeats in the detraining literature. Mujika and Padilla reviewed what happens when the stimulus disappears: in highly trained athletes, VO2max falls somewhere between 6 and 20% within 4 weeks of an insufficient training load, alongside a rapid drop in blood volume 7. The taper works because training continues at speed while the accumulated load drains away.

Elite runners cut less than the meta-analysis suggests. Spilsbury's group tracked pre-competition training in elite British runners and found tapers of 6 days for middle and long distance and 14 days for the marathon 8. Continuous running volume fell to 70%, 71% and 53% of regular levels, a smaller cut than the pooled data recommends. Interval intensity went the other way, with peak taper interval speed at 112% of race speed for long-distance runners and 114% for marathoners 8. These athletes trim easy kilometres and sharpen the fast ones, which is the same instruction Shepley's treadmill test produced in 1992.

The overload block has a ceiling.

The habit of hammering a final big week before backing off has been tested. Anaël Aubry's team put 33 trained triathletes through 3 weeks of overload training followed by a 4-week taper 9. Eleven of the 23 overloaded athletes crossed into functional overreaching, with performance down and perceived fatigue high. Their peak gain across the taper was 2.6% ± 1.1%, level with the control group's 2.6% ± 1.6%. The overloaded athletes who stayed merely fatigued gained more than both. Infections hit 70% of the overreached group against 20% of the fatigued group and 10% of controls 9. Push the last block hard enough to break yourself and the taper spends its weeks repairing you rather than sharpening you.

The protocol.

  1. Set the length by the distance. 14 days for 10 km through the half marathon, 21 days for a marathon or longer, with volume falling in every week of the taper 15.
  2. Land at 40 to 60% of your peak week. For a 3-week taper, run 80%, then 60%, then 45% of your biggest weekly volume. The pooled data favours a curve that falls every week over a single step down 15.
  3. Keep every quality session, cut its reps. 6 x 1 km at 10 km pace becomes 3 x 1 km at the same pace. Trim the volume of the hard session, never its speed 14.
  4. Run race week's intervals at or above race pace. Elite marathoners hit 114% of race speed in taper intervals, which for a 4:45/km marathon pace means repetitions at about 4:10/km 8.
  5. Keep the same number of runs. Drop at most one session per week and hold the rest, including the easy ones. Mujika and Padilla cap the cut in frequency at 20%, and the runners who rested through Shepley's taper gained nothing 46.
  6. Skip the final overload week if you are already flat. Two markers say you have gone past useful: a measured drop in performance, and high perceived fatigue lasting more than a few days. Extend the easy running instead 9.
  7. Write the taper down. Log your last 3 weekly volumes and your finish time across two races. A 3% swing on a marathon runs to around 6 minutes, wide enough to read off a stopwatch and decide which shape to keep.

Sources.

  1. Bosquet, L., Montpetit, J., Arvisais, D., & Mujika, I. (2007). Effects of tapering on performance: a meta-analysis. Medicine & Science in Sports & Exercise, 39(8), 1358-1365. link
  2. Wang, Z., Wang, Y., Gao, W., & Zhong, Y. (2023). Effects of tapering on performance in endurance athletes: a systematic review and meta-analysis. PLOS ONE, 18(5), e0282838. link
  3. Luden, N., Hayes, E., Galpin, A., Minchev, K., Jemiolo, B., Raue, U., Trappe, T., Harber, M., Bowers, T., & Trappe, S. (2010). Myocellular basis for tapering in competitive distance runners. Journal of Applied Physiology, 108(6), 1501-1509. link
  4. Shepley, B., MacDougall, J. D., Cipriano, N., Sutton, J. R., Tarnopolsky, M. A., & Coates, G. (1992). Physiological effects of tapering in highly trained athletes. Journal of Applied Physiology, 72(2), 706-711. link
  5. Smyth, B., & Lawlor, A. (2021). Longer disciplined tapers improve marathon performance for recreational runners. Frontiers in Sports and Active Living, 3, 735220. link
  6. Mujika, I., & Padilla, S. (2003). Scientific bases for precompetition tapering strategies. Medicine & Science in Sports & Exercise, 35(7), 1182-1187. link
  7. Mujika, I., & Padilla, S. (2000). Detraining: loss of training-induced physiological and performance adaptations. Part I: short term insufficient training stimulus. Sports Medicine, 30(2), 79-87. link
  8. Spilsbury, K. L., Fudge, B. W., Ingham, S. A., Faulkner, S. H., & Nimmo, M. A. (2015). Tapering strategies in elite British endurance runners. European Journal of Sport Science, 15(5), 367-373. link
  9. Aubry, A., Hausswirth, C., Louis, J., Coutts, A. J., & Le Meur, Y. (2014). Functional overreaching: the key to peak performance during the taper? Medicine & Science in Sports & Exercise, 46(9), 1769-1777. link

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