RESEARCH: Studies reviewed this week: 18 January 2021 to 24 January 2021

ALTITUDE: Hypoxic re‑exposure retains hematological but not performance adaptations post‑altitude training

What should you do after an altitude camp to optimize the benefits of that exposure? This study compared live-high-train-low (LHTL) using an altitude tent and live-low-train-low (LLTL) for the 3 weeks after a 3 week altitude camp.

The authors found that:

Altitude residence during a subsequent 3-weeks period training near sea level preserve the hematological acclimatization, whereas Hbmass gains are already lost nine days after the intervention if athletes resided at sea level.
Additional altitude exposure after the LHTH camp had no effect on physical performance indicators.
Our results also give support to empirical observations describing alternance of periods of improved (i.e., at day 4 and from day 9 to day 15).

PRACTICAL TAKEAWAY - coming down from altitude is complicated. If you are planning an altitude camp, then carefully consider how long before competition you return to sea level and also consider what interventions you apply during this period (LHTL).

NUTRITION: Fundamentals of glycogen metabolism for coaches and athletes

This excellent review is a useful reference and guide towards understanding glycogen and its impacts on performance.

In the abstract the authors outline the purpose of this paper:

Providing effective guidance to athletes and others wishing to enhance training adaptations and improve performance requires an understanding of the normal variations in muscle glycogen content in response to training and diet; the time required for adequate restoration of glycogen stores; the influence of the amount, type, and timing of carbohydrate intake on glycogen resynthesis; and the impact of other nutrients on glycogenesis.
This review highlights the practical implications of the latest research related to glycogen metabolism in physically active individuals to help sports dietitians, coaches, personal trainers, and other sports health professionals gain a fundamental understanding of glycogen metabolism, as well as related practical applications for enhancing training adaptations and preparing for competition.

PRACTICAL TAKEAWAY - glycogen stores have a significant impact on performance and it is important to understand this and how to account for it in your nutrition. This guide is highly recommended.

NUTRITION: Nutrition for Ultramarathon Running: Trail, Track, and Road

Following on from the study above, this particular paper provides some guidelines and advice for ultramarathon athletes. There are a few important sections of practical recommendations which make the advice in the paper very easy to try and to implement.

A few highlighted recommendations:

  • Alter the acute rate of intake (e.g., small and frequent intake), and experiment with higher intake rates early into running, since gastrointestinal symptoms are generally lower during the first 2 hr of running and then start to develop thereafter.
  • In longer races (≥8 hr) experiment with various easily digestible and carbohydrate-rich solid food sources. Avoid foods excessively rich in protein, fat, fiber, and fermentable oligo- di- monosaccharides and polyols.
  • In longer races (≥8 hr), in cases where tolerance to carbohydrate intake and gastrointestinal symptoms are an issue, mouth rinsing with a carbohydrate beverage may support the maintaining of workload through the oral cortex sensory network.
  • Avoid excessive sodium supplementation during running. Consume sodium based on food cravings. Do not use highly visible salt losses as a signal for increasing sodium intake.
  • If training and/or competing in hot ambient conditions (both dry and humid), prior heat acclimatization/acclimation is valuable as it results in plasma volume expansion.
  • Oliguria (limited urine output) is not necessarily a sign of dehydration. Avoid using urine measures of hydration (e.g., urine color, urine specific gravity, and urine osmolality) as a method of monitoring hydration status during ultramarathon running activities.

PRACTICAL TAKEAWAY - this is a useful paper to help prepare for your next ultramarathon. Definitely read the recommended guidelines and take home messages at the end of the paper.

NUTRITION: Effects of pre-sleep protein consumption on muscle-related outcomes

During heavy training periods I have used pre-sleep protein and it feels like it has helped my recovery (see this previous studies on protein for adaptation to endurance performance). This systematic review from 2020 investigated the impact of pre-sleep protein on "overnight muscle protein synthesis".

The results showed that:

Consumption of 20–40 g of casein ~30' before sleep stimulates whole-body protein synthesis rates overnight in young and elderly men.
Pre-sleep protein can augment the muscle adaptive response during 10–12 weeks of resistance exercise in young.

PRACTICAL TAKEAWAY - if you're in a training period with a heavy load or in a strength-focused training period, there may be benefit to consuming a protein supplement before sleep. The recommended dose is 20-40g of casein 30' before sleep.

TRAINING: Periodization: Variation in the Definition and Discrepancies in Study Design

I've used the terms periodization and programming interchangeably in the past so it's interesting to see that this issue of definition is a problem in the literature too.

The authors identify some problems:

  1. periodization has been the macro-management of the training concerning the annual plan, yet research on long-term effects is scarce;
  2. periodization and programming are being used interchangeably in research
  3. training is not periodized alongside other stressors such as sport.

Leading them to conclude:

Overall, the state of the literature suggests that the inability to define periodization makes the statement of its superiority difficult to experimentally test

PRACTICAL TAKEAWAY - it's difficult to tell how effective periodization is. Rather than trying to follow a best practice or research-based plan, do what works best for you.

PSYCHOLOGY: Persistence of Mental Fatigue on Motor Control

Mental fatigue impacts motor control and this is relatively well known (see this study on the impact of fatigue on pacing) and something many of us have experienced. In my own experience I know that later in ultramarathons I feel more clumsy and often kick rocks or have little stumbles that are not normal in my running. This study looked at how quickly we recover from mental fatigue.

The authors compared both the sensation of recovery and markers of recovery finding that:

Subjective measurements indicated a partial recovery of mental fatigue following a cognitively demanding task, whereas electrophysiological and behavioral markers suggested that the effects of mental fatigue persisted for at least 20 min.
Motivation and task-switching are possible ameliorating factors for the impact of mental fatigue on motor control.

PRACTICAL TAKEAWAY - if you're in a state of mental fatigue, it may be valuable to use the tactics of task-switching or to recall your motivation to reduce errors and potentially reduced performance.

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