RESEARCH: Studies reviewed this week: 31 May 2021 to 6 June 2021

NUTRITION: Carb-conscious: the role of carbohydrate intake in recovery from exercise

The window for recovery is often mentioned with regards to protein ingestion after exercise. However, it is also important to replenish glycogen stores especially if subsequent training sessions are to be performed in the same day or if high intensity sessions are planned in the following day. This review summarised the current evidence available on this topic. The authors highlighted that:

Three recent studies suggest this can extend time-to-exhaustion during endurance exercise tests.

This lead the authors to conclude:

To maximize recovery of glycogen stores and the capacity to perform in subsequent endurance exercise, athletes should consider ingesting at least 1.2 g carbohydrate per kilogram body mass per hour – for the first few hours of recovery – as a mixture of fructose and glucose-based carbohydrates.

PRACTICAL TAKEAWAY - it is important to replenish glycogen stores after exercising and this can best be done by using the same pathways that allow for more rapid absorption of CHO during exercise.

ALTITUDE: Relationship between changes in haemoglobin mass and maximal oxygen uptake after hypoxic exposure

Altitude training has been used to increase performance in athletes with the mechanism of adaption "thought to be accelerated erythropoiesis increasing haemoglobin mass (Hb(mass)) resulting in a greater maximal oxygen uptake". This study set out "a proportionate increase in VO₂(max) as a result of increased Hb(mass)".

In a large review that considered studies of 145 athletes during different altitude training camps, the authors concluded that:

Altitude training of endurance athletes will result in an increase in VO₂(max) of more than half the magnitude of the increase in Hb(mass), which supports the use of altitude training by athletes.

However, it is important to note:

Race performance is not perfectly related to relative VO₂(max), and other non-haematological factors altered from altitude training, such as running economy and lactate threshold, may also be beneficial to performance.

PRACTICAL TAKEAWAY - altitude training is beneficial for increasing Hb(mass), but it's important to consider all the factors affecting performance when planning an altitude taining camp.

NUTRITION: Comparison of the Effect of Soy protein and Whey protein on Body Composition

In this review the authors analyzed research papers that showed the benefits of either whey or soy protein on body composition. The findings were positive for whey:

There was a significant increase in lean body mass in individuals who received 12 or less weeks of whey protein. We observed no significant change between whey protein supplementation and body mass, fat mass, and body fat percentage.

While soy protein was not as effective:

No significant change between soy protein supplementation and lean body mass, body mass, fat mass, and body fat percentage.

PRACTICAL TAKEAWAY - if you're trying to improve your body composition, use whey and not soy protein.

HEAT: Temperate performance and metabolic adaptations following endurance training performed under environmental heat stress

In this study the authors "investigated whether exposure to 33°C during training would improve endurance performance in temperate conditions and stimulate mitochondrial adaptation". The study involved a three week training camp where training was performed at either 33C in the intervention or 18C in the control group.

Interestingly, the group that trained at higher temperatures had lower power outputs despite perceiving the same level of training load. The results showed that:

Time-trial performance improved to a greater extent in HEAT than TEMP.
Our data suggest exposure to moderate environmental heat stress during endurance training may be useful for inducing adaptations relevant to performance in temperate conditions.

PRACTICAL TAKEAWAY - training in hot conditions may improve performance despite lower training power outputs for the same effort.

NUTRITION: Capsaicinoid and Capsinoids as an Ergogenic Aid

This systematic review considered the benefit of capsaicinoid as ergogenic aids during exercise. The authors first explain what these are:

Capsaicinoids are the pungent compounds found primarily in chili peppers and other spicy foods. Capsaicin (trans-8-methyl-N-vanillyl-6-nonenamide) and dihydrocapsaicin (8-methyl-N-vanillylnonanamide) are among the most abundant capsaicinoids and are responsible for approximately 90% of total pungency.

The results showed that:

Our group recently investigated the effects of 12 mg of capsiate ingestion during high-intensity interval exercise in physically active men, and observed an increase in time to exhaustion without a concomitant change in blood lactate concentration or oxygen consumption during exercise and postexercise.
We also found that 12-mg capsiate ingestion increased the total volume performed during lower-body resistance exercise and decreased rating of perceived exertion (RPE).

PRACTICAL TAKEAWAY - capsaicinoid or capsinoid compounds showed significant improvement in endurance and resistance exercise.

INTERVALS: Superior Physiological Adaptations After a Microcycle of Short Intervals Versus Long Intervals in Cyclists

I like this study because it provides a useful answer to the question about what to do if you're planning a one week high-intensity training cycle. The authors set out to "compare the effects of a 1-week high-intensity aerobic-training shock microcycle composed of either 5 short-interval sessions (SI; n = 9, 5 series with 12 × 30-s work intervals interspersed with 15-s recovery and 3-min recovery between series) or 5 long-interval sessions (LI; n = 8, 6 series of 5-min work intervals with 2.5-min recovery between series) on indicators of endurance performance in well-trained cyclists".

The results of the study showed that:

From pretraining to posttraining, SI achieved a larger improvement than LI in maximal oxygen uptake and power output at a blood lactate concentration of 4 mmol/L.
SI can be a good strategy during a 1-week high-intensity aerobic-training shock microcycle in well-trained cyclists.

PRACTICAL TAKEAWAY - if you're intending to improve your performance with a one week high intensity training block, then short intervals are the way to go.

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