RESEARCH: Studies reviewed this week: 2 August 2021 to 8 August 2021

TRAINING: Session-RPE Method for Training Load Monitoring

RPE is a fantastic tool for managing your training load and effort. It's free, it's calibrated to your own sensations, and it doesn't require batteries. I've shared a number of studies (see resources page) that prove its validity as a measure. In this review the authors set out to review all the papers on RPE from 2001 to 2016. They conclude that:

These studies confirmed the validity and good reliability and internal consistency of session-RPE method in several sports and physical activities with men and women of different age categories (children, adolescents, and adults) among various expertise levels.
This method could be used as “standing alone” method for training load (TL) monitoring purposes though some recommend to combine it with other physiological parameters as heart rate.

PRACTICAL TAKEAWAY - RPE is a useful measure for training load and something you should track after each session.

CHO: Carbohydrate improves exercise capacity but does not affect subcellular lipid droplet morphology, AMPK and p53 signalling in human skeletal muscle

This study investigated "the effects of carbohydrate (CHO) feeding on lipid droplet (LD) morphology, muscle glycogen utilisation and exercise-induced skeletal muscle cell signalling". The participants followed a 36hr CHO-loading phase followed by a 180' exercise test and then muscle biopsy samples. The authors reported that:

Exercise reduces intramuscular triglycerides (IMTG) content in both central and peripheral regions of type I and IIa fibres, reflective of decreased LD number in both fibre types whereas reductions in LD size were exclusive to type I fibres.
Additionally, CHO feeding does not alter subcellular IMTG utilisation, LD morphology or muscle glycogen utilisation in type I or IIa/II fibres.

The authors concluded that:

In the absence of alterations to muscle fuel selection, CHO feeding does not attenuate cell signalling pathways with regulatory roles in mitochondrial biogenesis.

PRACTICAL TAKEAWAY - even in a state of high CHO it is possible for athletes to make adaptations that are beneficial for fat utilisation and endurance performance.

ALTITUDE: Determinants of maximal oxygen uptake in severe acute hypoxia

This slightly older study (2003) investigated the impact of hypoxia on performance. At a very high simulated altitude of 5300m the participants saw significant declines in performance:

Hypoxia caused a 47% decrease in VO2 max, and peak leg blood flow was also lower by 22%. Consequently, systemic and leg O2 delivery were reduced by 43 and 47% respectively.

The authors concluded that the mechanisms responsible for the decline in VO2 Max were:

  1. reduction of PiO2
  2. impairment of pulmonary gas exchange
  3. reduction of maximal cardiac output and peak leg blood flow

PRACTICAL TAKEAWAY - it's useful to know the factors that affect performance at altitude so we can understand the adaptations that occur when training in those conditions.

COVID: Impact of COVID-19 on exercise pathophysiology

The impact of COVID-19 on performance has not been extensively studied because it's obviously quite new. However, this study looked at "the extent and the determinants of exercise limitation in patients with COVID-19 at the time of hospital discharge". The authors found that:

When recovering from COVID-19, patients present with reduced exercise capacity and augmented exercise hyperventilation.
Peripheral factors, including anemia and reduced oxygen extraction by peripheral muscles were the major determinants of deranged exercise physiology.
Pulmonary vascular function seemed unaffected, despite restrictive lung changes.

PRACTICAL TAKEAWAY - COVID has a serious impact on patients who were hospitalized with a decrease in VO2 Max of 30%. Fortunately this does not appear to be a result of decreased pulmonary vascular function.

ALTITUDE: Absence of neocytolysis in humans returning from a 3-week high-altitude sojourn

The authors "performed a prospective study on erythrocyte survival after a stay at the Jungfraujoch Research Station (JFJRS; 3450 m)". This is useful to understand because it can help to inform us of the timing of competition after returning from altitude. The change in hemaglobin mass was reported as:

Tot-Hb increased by 4.7% ± 2.7% at high altitude and returned to pre-altitude values within 11 days after descent.

The authors conclude that the means of decrease on return from altitude is not neocytolysis:

Based on the lack of accelerated removal of age cohorts of erythrocytes labelled at high altitude, on patterns of changes in reticulocyte counts and of the band 4.1a/4.1b ratio and on modelling, this decrease did not occur via neocytolysis, but by a reduced rate of erythropoiesis along with normal clearance of senescent erythrocytes.

PRACTICAL TAKEAWAY - there appears to be a quick return to normal for tot-Hb mass after returning from altitude.

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