The physiology and application behind tapering are looked at by Jason Karp
I attended a high school that was known for its swimmers. They were the best in the country and some of them competed in the Olympics. Before championship meets, you could overhear amusing discussions in the hallways about “shaving down” and “tapering” in an attempt to swim faster. As a member of the cross country and track teams, I was also interested in getting faster, so I couldn’t help but eavesdrop. “What were these odd-sounding things,” I wondered. “Could they work for me, too? Do swimmers have a secret?”
The idea of progressively reducing, or tapering, the training load has been a long tradition among swimmers, the most often-studied athletes in regard to tapering. While it’s not necessary as a runner to shave all of your body hair to run faster, you may benefit from tapering your training. Since most runners are a driven bunch, it seems unnatural to cut your weekly running volume to a fraction of your current training. Competitive runners think they should always do more. But that’s one of the most interesting things about fitness – the adaptations to training occur during the recovery periods from the training, not during the training itself. When you taper your training, you provide your body the opportunity to recover, adapt and overcompensate to the training you’ve done so that you’re prepared to run your best race.
Performance effects of tapering
Most research on runners, swimmers and cyclists has shown that improved performance (from 0.5 to six per cent) is more likely to occur after a period of tapering. Studies on runners have been limited to 800m performance, time to fatigue on a treadmill at 1500m race pace, 5km performance and treadmill half-marathon performance. As with any type of training, these studies have shown a large individual response to tapering. One study using the 800m and another study using a treadmill half-marathon as the performance measure found that while tapering had a positive effect on selected physiological parameters, it did not have an effect on performance.
Physiological effects of tapering
Among the most prominent physiological changes that occur during the taper are in the characteristics of the blood, including increases in red blood cell volume, total blood volume, reticulocytes (immature red blood cells) and improvements in the health of red blood cells. These haematological changes reflect a positive balance between haemolysis (the degradation of red blood cells) and erythropoiesis (the production of red blood cells), leading to a greater oxygen carrying capability and, often, an improved performance.
Tapering also increases muscle glycogen content (giving you more fuel), aerobic enzyme activity (allowing for greater aerobic metabolism), muscular strength and power and it increases or maintains maximum oxygen consumption (VO2max). There is also a decreased level of the enzyme creatine kinase in the blood (an indirect indicator of muscle damage) which reflects an increased recovery.
The goal of tapering is to recover from prior training without compromising your previous training adaptations. In other words, you want to decrease fatigue without losing fitness. Unfortunately, research has not clearly established the time-frame separating the benefits of a successful taper from the negative consequences of insufficient training, leaving most athletes and coaches to take a trial and error approach. This is because studies on tapering in runners have only used one-week tapers and have not examined the taper’s effects on long-distance running performance. Typically, the longer the race, the longer the taper. The exact duration of your taper will vary depending on your prior training load, your level of fatigue and your genetically-predetermined ability to retain your training effects while reducing the training stimulus (how quickly you lose fitness). If you tend to fall out of shape fast, you don’t want a long taper. Positive physiological adaptations and performance gains have been found using tapers lasting six to seven days in university-aged runners, four to 14 days in cyclists and triathletes and 10 days in strength-trained athletes. Masters runners (over age 40) who take longer to recover from hard training may need to taper for longer than one week.
Taper volume and intensity
You can reduce your weekly running volume dramatically during the taper as long as you keep the intensity high. For example, one study found that middle-distance runners significantly improved treadmill time to fatigue at 1500m race pace and increased blood volume, aerobic enzyme activity and muscle glycogen concentration when using a one-week, low volume/high intensity taper (85 per cent reduction in volume and 5x500m at 800m race pace with six to seven minutes recovery, decreasing by one rep each day for five days), but not when using either a moderate-volume/low-intensity taper (10km at 60% VO2max, decreasing by two kilometres each day for five days) or a taper with no running at all. Other studies have also found that a large reduction in volume accompanied by an increase or maintenance in intensity improves training-induced adaptations.
Using a mathematical modeling approach, scientists discovered that training volume should be reduced in a progressive (linear or exponential) manner rather than by a single step reduction. Furthermore, overload training prior to the taper would result in a better performance post-taper than if overload training did not precede the taper. The researchers concluded that the best performance would be achieved with a 39 per cent reduction in training load for 28 days. If overload training does not precede the taper, the best performance would be achieved with a smaller reduction of training for a shorter period (31 per cent reduction for 19 days). Another study using both mathematical and experimental approaches also found that an exponential taper was better than a step-reduction taper and that a fast exponential taper was better than a slow exponential taper. In other words, reducing your training quickly and exponentially is better than reducing it slowly and in a single step.
You can probably expect to improve your racing performance by reducing your weekly mileage exponentially for one to two weeks (two to four weeks for the marathon) and including interval training (if you’ve already been doing so pre-taper) to maintain training intensity. As you get closer to your race, also reduce the volume of intensity by reducing the number of intervals in each session. Research has shown that reductions in training volume up to 60-90 per cent can improve performance, however the research is limited to much shorter races that are not as endurance-dependent as the marathon. Given the length of the marathon, and thus its large dependence on aerobic capacity, I wouldn’t recommend decreasing mileage by as much as 90 per cent.
For the marathon, I typically begin cutting my athletes’ volume and the length of their long runs three weeks before the race (or up to a week later if they haven’t been running high volume). I reduce peak mileage by 30 per cent for the first week, 50 per cent for the second week, and 65 per cent for the week of the marathon (not counting the marathon itself). I keep the intensity high during the first week, including one interval workout at 3km race pace and one moderately-long run (20-24 kilometres) with slightly less than half at lactate threshold pace (about 20-30 seconds per mile faster than marathon race pace for trained runners). Also, I begin to decrease the intensity slightly during the second week, including two short-to-medium distance runs (8-16 kilometres) at marathon race pace. The week of the race, I include one interval workout early in the week at either lactate threshold pace or slightly faster, cutting back on the pre-taper number of reps. The final week also includes a daily reduction in volume over the last few days that mirrors the pattern of the weekly reduction (see Pre-Marathon Taper box). Exactly what you do during your taper will depend on what you did before the taper.
If you want to give your performance a boost, try these tapering strategies before your next race. And if you taper smart enough, maybe you won’t have to shave your body hair!
Dr. Jason Karp PhD lives in San Diego, California and is a recognised speaker, writer, author and exercise physiologist.