|You are no triathlete or coach? That doesn't mean that this study isn't of interest for you. The figurative "extra wind" this training strategy can give you is relevant for almost every athlete.|
Scientists have long speculated that the disconnect between the benefits "training low" offers on the level of cellular / mitochondrial adaptation, on the one hand, and the real-world performance increases, on the other hand, could be a consequence of the necessarily reduced high intensity training intensity during the low-carb phases (Yeo. 2008; Hulston. 2010). If we simply assume that this hypothesis is correct, the solution to the problem should be obvious: Train low when carbohydrates are not necessary and use them, whenever they promote maximal performance.
Marquet et al. implemented this principle in a way I tried to illustrated in Figure 1. More specifically, they tried to maximize the subjects' performance during PM high-intensity training (HIT) by providing copious amounts of carbohydrates before the session and restricted the carbohydrate intake to close to zero after this glycogen-depleting workout.To test the efficacy of this protocol, the scientists used a 2x3 week study design in which the first 3 weeks were used to standardize the volunteers training regimen (10-15 h·wk- 1 : 40% running, 35% cycling, 25% swimming), assess subjects' compliance to the study demands and ensure they all attained similar baseline fitness measures before study commencement.
|Figure 1: Overview of important aspects of the dietary / supplemental aspects of the study.|
All subjects used their own training equipment to record their activity, the duration and intensity of exercise and heart rate. In conjunction with the volunteers' perceived exertion records, as well as VO2max tests, maximal and submaximal performance tests and the results of a simulation of the final leg of a triathlon race, the scientists got a pretty comprehensive set of data.
"consisted of six sessions over four consecutive days, including high intensity training (HIT) sessions in the afternoon and low intensity training (LIT) sessions the next morning. [...] LIT sessions consisted in 60 min cycling at 65% MAP (218.8 ± 20.4 W - 95% CI: 227.5 and 210.7), while HIT sessions consisted alternatively in 8 x 5 min cycling at 85% MAP (286 ± 26.7 W- 95% CI: 297.5 and 274.7) or 6x5 min running at their individual 10 km intensity with 1 min recovery between sets (37). [...] One LIT session per day was prescribed for the other days of the week for a total training volume of 10-15 h" (Marquet. 2016).
Figure 2: Sample weekly protocol for training and CHO intake (g/kg) to achieve different CHO avail. around training (Marquet. 2016) Figure 3: Make no mistake about it! The total amount of CHO the subjects consumed was identical it was just timed differently. No difference existed for any of the other macronutrients, either (Marquet. 2016).
- A similarly pronounced, albeit due to inter-individual differences, which loom large in studies with relatively few participants, only borderline significant (P = 0.06) beneficial effect was observed during the supra-maximal cycling to exhaustion trial at 150% of peak aerobic power, where the control group saw improve-ments of only 1.63 ± 12.4 %, while the "sleep low" group improved by 12.5 ± 19.0 %.
- The "sleep low" protocol also triggered significantly higher (P < 0.05) improvements in 10k running performance, where the meager -0.10 ± 2.03 % increase in the control group was topped by a -2.9 ± 2.15 % performance increase in the "sleep low" group.
- Hulston, Carl J., et al. "Training with low muscle glycogen enhances fat metabolism in well-trained cyclists." Medicine and science in sports and exercise 42 (2010): 2046-55.
- Marquet, et al. "Enhanced Endurance Performance by Periodization of CHO Intake: “Sleep Low” Strategy." Medicine & Science in Sports & Exercise (2015): Publish Ahead of Print.
- Yeo, Wee Kian, et al. "Skeletal muscle adaptation and performance responses to once a day versus twice every second day endurance training regimens." Journal of Applied Physiology 105.5 (2008): 1462-1470.