Effects of Taper on Endurance Cycling Capacity and Single Muscle Fiber Properties

Abstract

These results demonstrated that the metabolic properties of different fiber types are altered with tapering, that the type of taper protocol used influences their physiological adaptation, and that improvements in simulated 40-km endurance time were related to changes in metabolic properties of the muscle at the single fiber level.

Less Is More: The Physiological Basis for Tapering in Endurance, Strength, and Power Athletes

“…Initial muscle glycogen levels do not seem to affect short-term high-intensity performance (i.e., a sprint) [31,32]. Indeed, the performance decrements from overtraining [33] and the performance benefits from taper [26] can occur independent of muscle glycogen levels during shorter duration activities. However, initial glycogen levels do affect performance during repeated high-intensity efforts [34,35] as well as endurance efforts lasting ~60 min or more [36,37].…”

“…It enhances performance in shorter race events (i.e., 50 meter swim, <10 km cycling time trial [TT], 2000 m row) [4,7,13,[20][21][22] as well as middle distance swimming, biking, and running competition [4,5,9,13,20,[22][23][24]. Taper also improves performance indices in longer-duration events such as the duathlon [25], 40 km cycling TT [26], and triathlon [27,28]. For any distance event, it is reasonable to expect that taper will increase performance on the order of 2%-3%.…”

“…Reducing training volume for as long as four weeks [7] by >85% (in the last week) [6,19] still yields gains in performance without a loss of fitness. Considering the robust adaptations observed with short-duration high-intensity interval training, even in already highly trained individuals [26,27], it should come as no surprise that a well-designed taper of reduced volume and quality high intensity work can preserve fitness for up to a month. In strength athletes, short-term complete rest (≤1 week) does not reduce force-producing capacity while tapering only seems to improve strength [17].…”

“…Expanded muscle glycogen stores may therefore be a desirable taper-induced adaptation for endurance athletes, team sport athletes, and during activities requiring multiple individual efforts in quick succession. Other measures related to muscle energy usage such as lactate [4,9,10,13,23,38,39] and aerobic enzymes [8,10,26] are less affected by tapering. Taper-mediated muscle glycogen replenishment enhances performance in some circumstances but does not fully account for the beneficial effects of tapering.…”

“…However, it is the less abundant and 5-8 times more powerful fast-twitch fibers that drastically respond [5,22,26,28]. These fibers grow at an alarmingly fast rate with taper [5,22,26], improving power output without a measurable change in body mass [5,22]. Improved fast-twitch fiber function may allow for a harder "push" to the finish line or improve economy (faster speed with the same amount of effort).…”