RESEARCH: studies I shared this week: 8 to 14 August 2022

All of the studies I've shared (~500 studies) are available on the RESOURCES PAGE.

PHYSIOLOGY: Effects of training on lactate production and removal during progressive exercise in humans

Last week I shared a paper on lactate metabolism that looked at rats. There was a lot of discussion and great points shared on twitter about this topic which I'd recommend reading. This study looks at lactate metabolism in humans and the impact of training.

PRACTICAL TAKEAWAYS -

1. [Lactate parameters were] investigated in eight untrained men during progressive exercise before and after a 9-wk endurance training program.
2. [Training resulted in] the slower rise in blood [La] with increasing O2 uptake (VO2) after training due to a reduced lactate Ra at the lower work rates.
3. The lower blood [La] values during exercise after training in this study were caused by a diminished lactate Ra at low absolute and relative work rates and an elevated MCR at higher absolute and all relative work rates during exercise.

INTERVALS: Repeated-sprint training in heat and hypoxia: effect of exercise-to-rest ratio

PRACTICAL TAKEAWAYS -

1. Twelve male team-sport players completed two experimental sessions at a simulated altitude of ∼3000m, air temperature of 40°C and relative humidity of 50%.
2. Exercise involved either 3×5×10-s (E:R1:2) or 3×10×5-s (E:R1:4) maximal cycling sprints interspersed with active recoveries at 120W (20-s between sprints, 2.5 and 5-min between sets for E:R1:2 and E:R1:4 respectively).
3. These results indicate E:R1:4 increased mechanical power output and core temperature compared to E:R1:2.
4. Both protocols had different effects on measures of muscle oxygenation, with E:R1:2 generating greater muscle oxygen extraction and E:R1:4 producing more muscle oxygenation flux, which are both important signals for peripheral adaptation.
5. The E:R manipulation during RSH in the heat might be used to target different physiological and performance outcomes.

NUTRITION: Effect of a ketogenic diet versus Mediterranean diet on glycated hemoglobin in individuals with prediabetes and type 2 diabetes mellitus

PRACTICAL TAKEAWAYS -

1. We compared 2 low-carbohydrate diets with 3 key similarities (incorporating nonstarchy vegetables and avoiding added sugars and refined grains) and 3 key differences (incorporating compared with avoiding legumes, fruits, and whole, intact grains) for their effects on glucose control and cardiometabolic risk factors in individuals with prediabetes and T2DM.
2. The Wwell-formulated ketogenic diet (WFKD) led to a greater decrease in triglycerides, but also had potential untoward risks from elevated LDL cholesterol and lower nutrient intakes from avoiding legumes, fruits, and whole, intact grains, as well as being less sustainable.
3. The Mediterranean Plus diet avoiding refined sugars and refined grains and incorporating legumes, fruits, and whole, intact grains may be a superior option to a ketogenic diet.

TRAINING How do world class top 5 Giro d'Italia finishers train?

PRACTICAL TAKEAWAYS - surprising notes from this study:

1. Average training volume was less than I expected (15-20hrs). Peak volumes were 28-34hrs.
2. One athlete did not do altitude training.
3. None of these athletes did any off-the-bike strength training.

My friend Raul Celdran explained some of the errors or lack of detail in this study. He's going to help me with some more detailed data and studies to share in the future.

POWER: 9/3-Minute Running Critical Power Test: Mechanical Threshold Location With Respect to Ventilatory Thresholds and Maximum Oxygen Uptake

PRACTICAL TAKEAWAYS -

1. This study aimed to determine the CP location concerning anaerobic threshold, respiratory compensation point (RCP), and maximum oxygen uptake (VO2max).
2. No significant differences were obtained between CP and RCP in any of its units.
3. CP and RCP represent the same boundary in high-caliber athletes. These results suggest that coaches and athletes can determine the metabolic perturbance threshold that CP and RCP represent in an easy and accessible way.

Arcadi Margarit pointed out that another data point and a power duration curve would be more accurate; as well as noting that the second interval could be longer (10-12').

CHO: Effect of Carbohydrate Content in a Pre-event Meal on Endurance Performance-Determining Factors

PRACTICAL TAKEAWAYS -

1. A main effect of pre-event meal was found, with TTE being 8.0% longer following the high-CHO meal compared to the fasted state and 7.2% longer compared to the low-CHO meal.
2. No significant effect of pre-event meal on V∙O2peak, LT2, OBLA, or WE was found and no significant interaction effect between training status and pre-event CHO intake was found for TTE or any of the performance-determining variables.
3. High-CHO content in the pre-event meal led to a longer TTE compared to a meal with a low-CHO content or exercising in a fasted state, both in well-trained and recreationally trained participants.
4. The high-CHO meal was 3g/kg which consisted of white bread, jam, skimmed milk, oats, banana, and raisins.

EQUIPMENT: Effects of Acute High-Intensity Exercise With the Elevation Training Mask or Hypoxicator

PRACTICAL TAKEAWAYS -

1. There was no significant difference in metabolism or heart rate between conditions.
2. Human growth hormone increased with exercise, but no differences were found between conditions; however, a trend was observed for higher growth hormone after exercise in HYP vs. ETM
3. Elevation training mask does not seem to change acute pulmonary function, metabolism, heart rate, or oxygen saturation, indicating it likely does not create a hypoxic environment or mimic altitude.