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

NUTRITION: CHO - Carbohydrate Supplementation and the Influence of Breakfast on Fuel Use in Hypoxia

This study investigated carbohydrate supplementation to determine its effect on substrate utilisation in hypoxia. This is quite a specific study, but it can be useful to inform pre-exercise nutrition protocols and guide how best to fuel during training. The protocol consisted of participants either consuming breakfast or skipping it, and then either supplementing with CHO during their exercise (at a rate of 1.2g/min) or taking a placebo during exercise.

The authors found that:

In the first 60 min of exercise, there was no significant change in relative substrate oxidation in the carbohydrate compared with placebo trial after breakfast consumption or omission.
In the last 30 min of exercise, increased relative carbohydrate oxidation occurred in the carbohydrate compared with placebo trial after breakfast omission but not consumption.

The authors concluded:

In acute normobaric hypoxia, carbohydrate supplementation increased relative carbohydrate oxidation during exercise (>60 min) after breakfast omission, but not consumption.

PRACTICAL TAKEAWAY - if you're training at an altitude camp and you want to increase your CHO oxidation, skip breakfast and consume a CHO drink during your training session.

PSYCHOLOGY: Superstitious behavior in sport

Many of us have superstitions before races or in key training sessions, but have you ever wondered if this behavior is the same in elite athletes and which types of events they relate to? This literature set out to find what is available in the current research.

A few highlights include:

[Superstitious behaviors] increase with the level of challenge, as reflected by the importance of the competition, as well as with the level of uncertainty.
Cultural factors, in conjunction with the education level, as well as gender, have a strong influence on superstitious behaviors in sports.
Elite athletes are clearly more superstitious than non-elite athletes.

This led to the conclusions that:

An interaction between athletic skill and task-difficulty emerges to be another strong predictor of superstition in sport. It is evident that a set of complex personal and situational factors interact in the manifestation of superstitious behavior in sport that is used for the regulation of emotions in a quest for optimal performance.
The objective benefits (i.e., success) of superstition in sport may be ascribed to the placebo effect that yields an increased sense of control and mental reassurance in unpredictable contest situations.

PRACTICAL TAKEAWAY - superstitions are normal and a part of sport. There may even be some benefit from the placebo effect.

NUTRITION: SUPPLEMENT - Effect of Warm-Up and Sodium Bicarbonate Ingestion on 4-km Cycling Time-Trial Performance

A previous study I shared showed that sodium bicarbonate may be beneficial for sprint performance at the end of endurance races. This study tested different types of warm-ups to determine how this affects the benefits of sodium bicarbonate ingestion for performance. The study was very thorough - it was a doubleblind, block-randomized crossover study with 6 lab visits and 4 TT tests per visit.

The authors found that:

Performance was faster for control warm-up + NaHCO3 (CWSB) versus intermittent warm-up + NaHCO3 (IWSB) and control warm-up + placebo (CWP).
Pre-TT bicarbonate concentration was elevated for CWSB versus IWSB and CWP
Post-TT blood lactate concentration was elevated for CWSB versus CWP.

PRACTICAL TAKEAWAY - a continuous warm-up (in this study 17' at 150W) is better than an intermittant warm-up (short intervals at various intensities) if you want to take advantage of the ergogenic benefits of sodium bicarbonate. I would suggest if you're going to take sodium bicarbonate and risk the potential GI issues that are often associated with it, you should do everything you can to maximise the advantage of taking it.

RECOVERY: Business Class Travel Preserves Sleep Quality and Quantity and Minimizes Jet Lag During the ICC Women’s T20 World Cup

This study helps to answer a simple question: should you fly business class for you important competitions? The authors found that:

Players with higher in-flight sleep efficiency reported higher ratings for fatigue (ie, lower perceived fatigue) during the tournament period.
Tournament sleep duration was longer, and bed and wake times were earlier compared with habitual.
Maximizing in-flight sleep quality and quantity appears to have implications for recovery and sleep exhibited during competition.

PRACTICAL TAKEAWAY - if you can afford it, business class travel can have implications for race performance at your destination.

TRAINING LOAD: Monitoring Rating of Perceived Exertion Time in Zone: A Novel Method to Quantify Training Load in Elite Open-Water Swimmers?

This study looked at different metrics and means of monitoring training load in open-water swimmers. The various metrics considered were:

Heart-rate-based methods, such as time in zone (TIZ), session goal (SG), and hybrid (SG/TIZ), were used to analyze TID. Similarly to SG/TIZ, a new hybrid approach, the rating of perceived exertion (RPE)/TIZ for a more accurate analysis of TID was used.

The authors found that:

Heart-rate- and RPE-based TID methods were significantly different in quantifying Z1 and Z2, while no difference was observed in the quantification of Z3.
Using RPE-based TID methods, Z2 was significantly larger compared with Z1.

PRACTICAL TAKEAWAY - how you monitor training load needs to carefully consider the type of training and means of measuring its intensity. I suspect for swimmers who use a lot of interval or broken-style sessions, there is a significant part of each interval which is at a high intensity but occurs before HR has increased skewing the training load towards more Z1 values if HR training loads are used.

No comments: