RESEARCH: Studies reviewed this week: 30 November 2020 to 06 December 2020

HEAT: Intermittent post-exercise sauna bathing improves markers of exercise capacity in hot and temperate conditions in trained middle-distance runners

In the previous studies I shared about heat adaptation, it was shown that post-exercise hot water immersion can result in adaptation, post-training sauna bath enhanced endurance performance, but that a heat training camp and hot-water immersion together did not have any additional benefit. In this study the authors set out to "intermittent post-exercise sauna bathing across three-weeks endurance training improves exercise heat tolerance and exercise performance markers in temperate conditions, compared to endurance training alone".

The protocol for the post-exercise sauna group was 3-4 sauna sessions of ~30' each week for three weeks. The authors found that:

Three-weeks post-exercise sauna bathing is an effective and pragmatic method of heat acclimation, and an effective ergogenic aid.

A useful additional point from the study was about the extension of the heat-training period:

Extending the intervention to seven weeks only marginally improved rectal temperatute [and not performance].

PRACTICAL TAKE AWAY - a three-week heat training protocol of sauna baths may be effective to prepare for a race in hot conditions.

ALTITUDE: Heart rate variability during the first week of an altitude training camp is representative of individual training adaptation at the end of the camp in elite triathletes

In two previous studies I've shared the need to carefully understand adaptation to altitude has been mentioned: elite athletes trained at high intensity quite soon after arriving at altitude, and, a LHTL approach is best modulated and this can be done with HRV. In this study the authors set out to:

Determine whether changes in HR and HRV during the beginning of a 3-week training camp at altitude would be representative of training adaptation at the end of the training camp in elite triathletes.

The authors found that:

  • Resting HR was more elevated during the first week at altitude for non-responders;
  • The CV rMSSD also increased at a greater rate for non-responders;
  • The difference between rMSSD pre-camp and in the first week of camp was lower for non-responders.

This led the authors to provide the following practical recommendations:

Practitioners should monitor HR and HRV during the first week of camp and if a poor response is shown then adaptations to training load should be applied.

PRACTICAL TAKE AWAY - HR and HRV measurements during training camp can be an effective way to adapt and adjust training prescription at altitude.

SLEEP: Sleep Hygiene and Light Exposure Can Improve Performance Following Long-Haul Air Travel

In this study the authors set out to "assess the efficacy of a combined light exposure and sleep hygiene intervention to improve team-sport performance following eastward long-haul transmeridian travel". One group of athletes was provided with a light exposure and sleep hygiene plan that resulted in greater sleep duration during travel and in the four days post travel. In the performance tests the intervention group performed better than the control group leading the authors to conclude:

Combined light exposure and sleep hygiene improved speed and power but not intermittent-sprint performance up to 96 hours following long-haul transmeridian travel. The reduction of sleep disruption during and following travel is a likely contributor to improved performance.

PRACTICAL TAKE AWAY - make sure that you have a good plan for your sleep patterns when travelling to ensure optimal performance at a race.

DOWNHILLS: Trail Runners Cannot Reach VO2Max during a Maximal Incremental Downhill Test

I like this study because it sets out to quantify and better understand something that most trail runners know intuitively: that it's much harder to reach maximal efforts during downhill running. The purpose of the study was two-fold:

  • determine if well-trained athletes can achieve similar peak oxygen uptake (VO2peak) in downhill running (DR) versus level running (LR) or uphill running (UR);
  • investigate if lower limb extensor muscle strength is related to the velocity at VO2peak (vVO2peak) in DR, LR, and UR.

The authors found that:

Oxygen uptake at maximal effort was approximately 16% to 18% lower in DR versus LR and UR. At similar VO2, higher heart rate and ventilation emerged in DR versus LR and UR, associated with a more superficial ventilation pattern.
This study demonstrates that well-trained endurance athletes, accustomed to DR, achieved lower VO2peak despite higher vVO2peak during DR versus LR or UR maximal incremental tests.

PRACTICAL TAKE AWAY - it is important to consider the various demands of a trail race to ensure optimal performance. The lower VO2 Max during downhill running may be an opportunity to recover aerobically, while the muscular demands of downhill running may need to be specifically prepared for to ensure optimal performance.

HEAT: The effect of medium-term heat acclimation on endurance performance in a temperate environment

Another heat acclimation study this time investigating an 11-day heat acclimation protocol on endurance performance. In this case, the athletes trained in the heat (it was not a post-exercise protocol or a training camp at heat) for 11 consecutive days for 60-90' at 40C (HA) compared to a control that exercised at 11C (CON). The authors found that:

  • HA reduced resting and exercising rectal temperature, and increased whole-body sweating, with no change in CON.
  • Plasma volume increased in HA and CON with no between-groups difference, whereas exercise heart rate reduced in both groups, but to a greater extent in HA than CON.
  • VO2max, lactate threshold and mechanical efficiency were unaffected by HA.
  • 11-days HA induces thermophysiological adaptations, but does not alter the key determinants of endurance performance.

PRACTICAL TAKE AWAY - heat adaptation does not necessarily improve performance in temperate conditions. It seems that a heat adaptation protocol may provide the most benefit for athletes preparing to race in hot conditions and is not necessary for other performance conditions.

RECOVERY: Does Cold-Water Immersion After Strength Training Attenuate Training Adaptation?

In a previous study I shared the authors showed that cold-water immersion did not accelerate recovery after a 10km running race. This study set out to investigate whether or not cold-water immersion would benefit strength training. The protocol tested was 10' whole-body water immersion post-exercise. The authors found that:

No significant effects were found for strength or jump performance. Comparing training adaptations (pre vs post), small and negligible negative effects of cooling were found for 1-repetition maximum and countermovement jump.
The present investigation suggests small negative effects of regular cooling on strength training adaptations.

PRACTICAL TAKE AWAY - you don't need to do an ice bath after training and in fact this may negatively affect the adaptation to training.

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