RESEARCH: studies I reviewed this week: 20 June to 3 July 2022

PHYSIOLOGY: Oxygen Uptake Measurements and Rate of Perceived Exertion During a Marathon

In this study the authors followed continous breath-by-breath gas exchange measurements during a marathon. Then they examined the RPE and physiological parameters throughout the marathon to determine whether or not RPE can be used to control marathon pace. I thought the means of monitoring RPE to be quite interesting:

The RPE was recorded by the runners using a small microphone that they carried with them. The runners recorded an RPE at least every km or more frequently if they felt the need. We used the Borg 6–20 scale [16] scale to assess fatigue during the marathon as a correlate to the physiological stress indicators. The runners were familiarized with the scale during the 2 weeks preceding the race.

The authors found:

The systematic increase of the respiratory frequency in all but one runner led us to hypothesize that these are good candidates for pace regulation during a marathon.
In the present study, all the marathoners (but one) ran in “positive split,” that is to say, with a speed decrease trend in accordance with prior study with an extremely low value of risk α associated with the same tendency for the both components of the runners’ speed.
Only the respiratory frequency and heart rate increased progressively during the race in all the runners, while the oxygen uptake and ventilatory rate followed different kinetics according the individuals. However, the indexation of the physiological parameters and speed by RPE showed the same decreased tendency for all the runners.

PRACTICAL TAKEAWAY - the results suggest that running a marathon based on RPE (rather than other measured physiological variables) is the most effective way to self-pace.

PHYSIOLOGY: Anaerobic Threshold Determination in Cycle Ergometer From Rating of Perceived Exertion

Looking further at RPE, this time a study with the " investigate the validity of the rating of perceived exertion threshold (TRPE) for anaerobic threshold (AT) estimation during an incremental test (IT) on a cycle ergometer". The authors found that:

There was a strong correlation between the intensities in AT and TRPE during the IT.
A substantial reliability was evidenced, as well as a substantial agreement between the AT and TRPE intensities.

PRACTICAL TAKEAWAY - we have a good sense of where the anaerobic threshold is and can use this RPE guided intensity during training and racing.

SLEEP: The influence of sleep and training load on illness in nationally competitive male Australian Football athletes

These authors set out to determine "the incidence of illness, and identify the relationship between sleep, training load and illness in nationally competitive Australian football athletes". The findings showed that:

Univariate analysis showed acute and chronic sleep hours and quality, as well as acute sprint and total running distance to be significantly associated with illness.
Multivariate analysis identified that only acute sleep quantity was significantly, negatively associated with illness incidence (OR 0.49, CI 0.25–0.94) once all univariate significant variables were controlled for.
Reduced sleep quantity was associated with increased incidence of illness within the next 7 days.

PRACTICAL TAKEAWAY - make sure to sleep enough!

PHYSIOLOGY: Disparate Mechanisms of Fatigability in Response to Prolonged Running versus Cycling of Matched Intensity and Duration

Endurance athletes often engage in multiple different sports and ultramarathon runners in particular are often run and cycle. However, it can be difficult to compare the demands of these two sports and therefore to programme them effectively in a training plan. This study set out "to compare the alterations in neuromuscular function induced by matched-intensity and duration cycling and running exercise".

The testing protocol was:

During separate visits, 17 endurance-trained male participants performed 3 h of cycling and running at 105% of the gas exchange threshold. Neuromuscular assessments were taken are preexercise, midexercise, and postexercise.

The findings showed that:

Reductions in voluntary activation (VA) were greater after running (−16% ± 10%) than cycling (−10% ± 5%).
Reductions in thoracic motor evoked potentials (TMEP) were greater after running (−78% ± 24%) than cycling (−15% ± 60%).

The authors concluded that:

Running-based endurance exercise is associated with greater impairments in nervous system function, particularly at the spinal level, whereas cycling-based exercise elicits greater impairments in contractile function.

PRACTICAL TAKEAWAY - it is important to understand the demands of an exercise to know how to plan it and how much recovery is required. There are differences between running and cycling and these need to be accounted for in training plans.

NUTRITION: “Food First but Not Always Food Only”: Recommendations for Using Dietary Supplements in Sport

In this paper the authors explore the idea of a "food first" approach to sports nutrition where they provide their own definition:

Food first should mean “where practically possible, nutrient provision should come from whole foods and drinks rather than from isolated food components or dietary supplements.”

They explain why a food only approach may not always be optimal for athletes:

  1. some nutrients are difficult to obtain in sufficient quantities in the diet, or may require excessive energy intake and/or consumption of other nutrients;
  2. some nutrients are abundant only in foods athletes do not eat/like;
  3. the nutrient content of some foods with established ergogenic benefits is highly variable;
  4. concentrated doses of some nutrients are required to correct deficiencies and/or promote immune tolerance;
  5. some foods may be difficult to consume immediately before, during or immediately after exercise; and
  6. tested supplements could help where there are concerns about food hygiene or contamination.

PRACTICAL TAKEAWAY - food first is a good approach, but using supplements when necessary should be encouraged.

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