RESEARCH: studies I shared this week: 7 to 13 November 2022

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

PHYSIOLOGY: Maximal Fat Oxidation Rates in an Athletic Population

STUDY DETAILS -

1. In total, 1121 athletes (933 males and 188 females), from a variety of sports and competitive level, undertook a graded exercise test on a treadmill in a fasted state (≥5 h fasted). Rates of fat oxidation were determined using indirect calorimetry.
2. In absolute terms, male athletes had significantly higher MFO compared with females.
3. Soccer players had the highest MFO/FFM, whereas American Football players displayed the lowest rates of MFO/FFM.
4. In all athletes, and when separated by sport, large individual variations in MFO rates were observed.
5. Significant positive correlations were found between MFO (g·min) and the following variables: FFM, V˙O2max, FATMAX (the exercise intensity at which the MFO was observed), percent body fat, and duration of fasting.

PRACTICAL TAKEAWAY - there are large variations of maximal fat oxidation across athletes most likely determined by genetics, diet, and training.

TRAINING: Critical power and work-prime account for variability in endurance training adaptations not captured by V̇o2max

STUDY DETAILS -

1. Responses to exercise at a given percentage of one’s maximum rate of oxygen consumption (V̇o2max), or percentage of the power associated with V̇o2max during a graded exercise test (i.e., PGXT), vary.
2. PCRIT, W′, V̇o2max, and other variables were determined before and after 22 adults completed 8 wk of either moderate-intensity continuous training (MICT) or high-intensity interval training (HIIT) performed at fixed percentages of PGXT.
3. The intensity of the prescribed exercise relative to pretraining PCRIT, not PGXT, accounted for most of the variance in changes to PCRIT in response to a given protocol.
4. Training-induced changes in time-to-failure at the initial PGXT were better captured by the combined changes in W′ and PCRIT, than by the change in V̇o2max.
5. In this study we demonstrate that training-induced changes in endurance are more strongly related to the intensity of an exercise training program, relative to PCRIT than relative to V̇o2max.
6. Thus, exercise may be more homogenously and effectively prescribed in relation to PCRIT than traditional factors like V̇o2max.

PRACTICAL TAKEAWAY - critical power may be a more useful means of prescribing intensity than using a percent of VO2 Max.

PHYSIOLOGY: Alterations in spontaneous electrical brain activity after an extreme mountain ultramarathon

STUDY DETAILS -

1. This study aimed to investigate the impact of an extreme mountain ultramarathon (MUM) on spontaneous electrical brain activity in a group of 16 finishers.
2. By using 4-minute high-density electroencephalographic (EEG) recordings with eyes closed before and after a 330-km race (mean duration: 125 ± 17 h; sleep duration: 7.7 ± 2.9 h), spectral power, source localization and microstate analyses were conducted.
3. After the race, power analyses revealed a centrally localized increase in power in the delta (0.5–3.5 Hz) and theta (4.0–7.5 Hz) frequency bands and a decrease in alpha (8.0–12.0 Hz) power at the parieto-occipital sites.
4. These changes in power patterns and microstate parameters contrast with previously reported findings following short bouts of endurance exercises.
5. This neurocognitive concept supports the idea of a reallocation of the brain’s resources to sustain the neural activation of motor, sensory and autonomic systems with a concomitant deactivation of the neural structures that are not crucial during an acute physical exercise (mainly the frontal regions that are occupy by cognitive functions).
6. In ultramarathons, sleep deprivation likely has a strong effect on functional brain reorganization.

PRACTICAL TAKEAWAY - awareness that extremely long ultramarathons are impacting the brain's allocation of resources (to motion and away from cognitive functions) can help us to determine sleep strategies and stop athletes who may be at higher risk during sleep deprivation.

NUTRITION: Ketogenic Diets and Mitochondrial Function: Benefits for Aging but not for Athletes

STUDY DETAILS -

1. A ketogenic diet (KD) increases longevity 13.6% in mice
2. A KD increases skeletal muscle mitochondrial mass and activity as well as measures of muscle strength (grip force), and endurance (wire hang) in aged mice.
3. A ketogenic diet activates the peroxisome proliferator-activated receptor (PPAR) family of transcription factors resulting in an increase in the enzymes necessary to transport and oxidize fatty acids as a fuel.
4. The PPARs also increase pyruvate dehydrogenase kinases that limit the rate of carbohydrate oxidation, resulting in impaired glucose utilization and impaired elite performance.

PRACTICAL TAKEAWAY - a ketogenic diet may be beneficial when aging.

TRAINING: Integrative Proposals of Sports Monitoring: Subjective Outperforms Objective Monitoring

STUDY DETAILS -

1. Current trends in sports monitoring are characterized by the massive collection of tech-based biomechanical, physiological and performance data, integrated through mathematical algorithms.
2. There is a disconnect between the complexity underpinning human health and performance and the deterministic models through which athletic monitoring and assessment are conceptualized.
3. While focusing on collecting and processing large amounts of data, analysts, scientists and coaches may forget the outstanding potential of the human neurobiological system to dynamically, and rapidly, integrate massive amounts of personal and environmental information.
4. The pillars of an effective subjective monitoring are athletes’ self-sufficiency, self-consciousness, autonomy and honesty.
5. Critically, in the future, there is a need to evolve more discerning methods for creatively capturing, interpreting and presenting subjective athlete-generated information.

PRACTICAL TAKEAWAY - athletes and coaches should use both subjective and objective measures to monitor their training.

STRENGTH: Resistance training volume does not influence lean mass preservation during energy restriction in trained males

STUDY DETAILS -

1. This study investigated the effects of a relatively high- versus moderate-volume resistance training program on changes in lean mass during caloric restriction.
2. High-volume resistance training appears to have neither an advantage nor disadvantage over moderate-volume resistance training in terms of maintaining lean mass or muscle thickness.
3. Given that both groups increased volume load and maintained muscle contractility, sleep quality, and mood, either moderate or higher training volumes conceivably can be employed by resistance-trained individuals to preserve muscle during periods of moderate caloric restriction.

PRACTICAL TAKEAWAY - if you intend to perform resistance training to maintain muscle mass during calorie restriction, the training does not have to be high-volume, moderate volume will be just as effective.