RESEARCH: studies reviewed this week - 27 July 2020 to 2 August 2020

TRAINING: Quantifying the Training-Intensity Distribution in Middle-Distance Runners: The Influence of Different Methods of Training-Intensity Quantification

There are multiple different ways to measure intensity for runners. I have typically prioritised heart rate (HR) and rate of perceived exertion (RPE) because pace is not very useful for running on trails and with large changes in altitude. I thought that the different means of achieving an intensity would result in a similar training-intensity distribution (TID) so I was particularly interested to see if this held up under test conditions.

The authors set out "to compare the training-intensity distribution across an 8-week training period in a group of highly trained middle-distance runners employing 3 different methods of training-intensity quantification". They found that:

Compared with the running-speed-derived TID, HR-demarcated TID resulted in a substantially higher training time in zone 2 and lower training time in zone 3.

RPE-derived TID reduced time in zone 1 compared with both HR and running speed, whereas time in RPE training zones 2 and 3 was substantially higher than both HR- and running-speed-derived zones.

The results show that the method of training-intensity quantification substantially affects computation of TID.

PRACTICAL TAKE AWAY - how intensity is prescribed in training can have a significant impact on what is actually executed in the training session. Choose the prescription method with the training goal in mind.

TRAINING: Eleven-Week Preparation Involving Polarized Intensity Distribution Is Not Superior to Pyramidal Distribution in National Elite Rowers

Structuring and planning training places a high level of importance on the distribution of intensity in the training plan. Polarised training (POL) emphasizes "high-volume low-intensity exercise in zone (Z)1 (< first lactate threshold) with a greater proportion of high-intensity Z3 (>second lactate threshold) compared to Z2 (between first and second lactate threshold). This type of training has been shown to be valuable for endurance athletes in shorter events. Pyramidal training where greater volume of training occurs in Z1 vs. Z2 vs. Z3 is typically favored by athletes taking part in longer events where top end speed is less important.

This study set out to resolve the "lack of prospective controlled evidence whether POL is superior to pyramidal (PYR)TID". The aim of the study was to compare the effect of POL vs. PYR TID in rowers during an 11-wk preparation period. The results showed that:

Changes from pre to post were not significantly different between groups in any performance measure.
POL did not prove to be superior to PYR, possibly due to the high and very similar percentage of Z1 in this study.

PRACTICAL TAKE AWAY - it appears that as long as a large percent of training is taking place in Z1 (>90% in this study), it does not matter how that last few percent at higher intensity is achieved (in either Z2 or Z3). This may make training prescription easier: mostly low intensity with small amounts at higher intensity (could be Z2 or Z3).

NUTRITION: Carbohydrate Hydrogel Products Do Not Improve Performance or Gastrointestinal Distress During Moderate-Intensity Endurance Exercise

Race diet plays an important part in determining performance. I've shared previous studies showing that including some fat and drinks more fluid may reduce GI distress and also that calorie, fluid, fat and sodium consumption were greater in finishers compared to non-finishers of an ultra-marathon. One of the more recent nutrition interventions that has proposed to reduce GI distress and increase CHO availability is carbohydrate hydrogels.

This review on the research available on hydrogels showed that:

A positive finding from this review is that hydrogel formulations were generally well tolerated across the range of doses and exercise protocols that were examined. However, hydrogel solutions did not improve GI tolerance per se above comparable CHO sources in traditional fluid form.

It remains to be seen if they systematically reduce GI symptoms at higher doses approaching and above intestinal saturation, due to specific interaction with the digestive system.

Reports of a slight increase in gastric fullness associated with the hydrogel are of interest, since even if there is a subsequent increase in gastric emptying associated with the formation of the gel, it may create an initial sensation of fullness.

The authors conclude that:

A small number of studies have investigated the use of commercially available CHO hydrogels to deliver CHO during exercise. So far, data do not support the claimed benefits of enhanced CHO delivery to the muscle, reduced GI distress, and better performance compared with the use of traditional CHO solutions.

PRACTICAL TAKE AWAY - hydrogels do not provide performance benefit above traditional CHO sources.

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