RESEARCH: studies reviewed this week - 13 July 2020 to 19 July 2020

TRAINING: Training for a (half‐)marathon: Training volume and longest endurance run related to performance and running injuries

I like studies that look at real training and performance and then try to pull out the details and useful information that can be implemented into training. While the point that more training volume (especially starting off a low base) and longer, long runs improved performance seems to be a logical and obvious relationship, the impact this had on injuries is important to note. The authors found that:

In half‐marathon runners, a high training volume (>32 km/wk) and a long endurance run (>21 km) were associated with a faster finish time, while a high training volume and a long endurance run were also related to less decline in pace.
In marathon runners, a low training volume (<40 km/wk) was related to a slower finish time and a high training volume (>65 km/wk) to a faster finish time, while a longest endurance run of <25 km was associated with a slower finish time.

Importantly, the study found there was:

no associations between training characteristics and RRIs were identified.

PRACTICAL TAKE AWAY - increasing training volume and long-run duration will improve performance without adding to injury risk.

NUTRITION: The impact of type of dietary protein, animal versus vegetable, in modifying cardiometabolic risk factors

"The aim of this expert opinion recommendation was to elucidate the different impact of animal vs vegetable protein on modifying cardiometabolic risk factors." This sort of study is useful because it provides information on what to actually eat rather than a guideline based on values or metrics. I try to follow the advice from Dr Stuart Phillips on protein intake (my notes from his presentation at the LPC Nutrition Conference here) and one of his guidelines is that dairy is a great source of leucine. This study makes the following suggestions regarding protein intake:

It is recommended to substitute red meat with poultry or fish in order to lower cardiovascular disease risk.
Apart from meat, other animal-source proteins, like those found in dairy products (especially whey protein) are inversely correlated to hypertension, obesity and insulin resistance.

PRACTICAL TAKE AWAY - animal-source protein is good for your health, although it may be useful to avoid red meat.

NUTRITION: The Effectiveness of Daily and Alternate Day Oral Iron Supplementation in Athletes With Suboptimal Iron Status (Part 2)

I struggle with races that go up to high altitude and therefore when possible I try to do an altitude acclimation camp before these races. In the past I have taken an iron supplement every day when at altitude and I believe that it helps with the acclimation process. However, I have also had stomach issues with iron supplements and that can be challenging along with the difficulty of training at altitude.

I found this study particularly interesting at it showed that taking alternating day supplements is as effective for improving serum ferritin (sFer) while reducing the occurrence of gastrointestinal side effects. The key findings were:

sFer did increase over the 8-week intervention in both groups (every day supplement and alternate day supplement)...and that...there were six complaints of severe gastrointestinal side effects in DAY, but only one in ALT.

PRACTICAL TAKE AWAY - taking iron supplements on alternating days is as effective as taking it every day and this approach could reduce gastrointestinal issues.

PHYSIOLOGY: Exercise Training Increases Size of Hippocampus and Improves Memory

We know that exercise is good for you. This study goes even further and investigates the effect on the brain and memory. The benefits are clear and make a good case for continuing to exercise for our entire lives. The study shows:

In a randomized controlled trial with 120 older adults, that aerobic exercise training increases the size of the anterior hippocampus, leading to improvements in spatial memory. Exercise training increased hippocampal volume by 2%, effectively reversing age-related loss in volume by 1 to 2 y.
These theoretically important findings indicate that aerobic exercise training is effective at reversing hippocampal volume loss in late adulthood, which is accompanied by improved memory function.

PRACTICAL TAKE AWAY - keep exercising even in late adulthood!

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