RESEARCH: studies from May 2022

CAFFEINE: Caffeine Supplementation Strategies Among Endurance Athletes

I enjoy these types of studies that investigate whether athletes actually follow the guidelines recommended by research. Firstly it provides an opportunity to learn what athletes are actually doing. Secondly it acts as a reminder to check my own practice and see whether or not I'm complying with the things I've learned through reviewing research. In this study the authors set out "to investigate caffeine supplementation protocols among endurance athletes".

They found that:

Most participants reported habitual caffeine consumption (85.0%; 41.2% multiple times daily). However, only 24.0% used caffeine supplements. A greater proportion of men (31.7%) used caffeine supplements compared with women (17.2%).
Of those reporting specific timing of caffeine supplementation, 49.1% and 34.9% reported consuming caffeine within 30 min of training and races respectively; 38.6 and 36.5% used caffeine 30–60 min before training and races.
It appears that recreational athletes use lower caffeine amounts than what has been established as ergogenic in laboratory protocols; further, they consume caffeine closer to exercise compared with typical research protocols.

PRACTICAL TAKEAWAY - most athletes do not follow the recommendations to use "doses of 3–6 mg/kg of caffeine 60 min prior to exercise". There are definitely benefits from using caffeine so make sure to check your own practice and follow the research guidelines.

STRENGTH: Effects of Isometric Strength and Plyometric Training on Running Performance

I've share studies in the past about explosive strength training, depth jumps, and complex strength training and their impact on running economy. In this randomized contolled study the authors explored the benefits of plyometrics (PT) and isomestric (IST) on running economy. They found that:

Significant time x group interactions and time main effect were observed for 2.4kmTT, maximal aerobic speed (MAS), CMJ height and isometric mid-thigh pull (IMTP) relative peak force in favor of PT and IST.

They conclude that:

Both PT and IST were similarly effective at enhancing running endurance performance. However, IST resulted in greater improvement to RE.

PRACTICAL TAKEAWAY - plyometrics and isometric strength training can improve running economy. Isometric exercises may also be less risky due to their static motion.

CREATINE - Effects of Oral Creatine Supplementation on Power Output during Repeated Treadmill Sprinting

This study on creatine set out to determine "the effects of creatine (Cr) supplementation on power output during repeated sprints". The speint was 6x10" on a motorized treadmill and the dose of the intervention group was 75mg/kg/day. The results showed that:

After Cr supplementation, body mass was increased by 0.99 ± 0.83 kg, peak power output and peak running speed remained unchanged throughout the test in both groups, while the mean power output and mean running speed during the last 5 s of the sprints increased by 4.5% and 4.2% to 7.0%, respectively, during the last three sprints.
The reduction in speed within each sprint was also blunted by 16.2% following Cr supplementation. Plasma ammonia decreased by 20.1% after Cr supplementation, despite the increase in performance.
VO2 and blood lactate during the repeated sprints test remained unchanged after supplementation, suggesting no alteration of aerobic or glycolytic contribution to adenosine triphosphate production.

PRACTICAL TAKEAWAY - creatine supplementation improved power and speed in the second half of short (10") sprints. If you're a sprinter or performing repeated sprints then supplementing with creatine is an important as the potential benefits are significant.

PHYSIOLOGY: How Strongly Does Appetite Counter Weight Loss?

In this study the authors set out "to quantify the feedback control of energy intake in response to long-term covert manipulation of energy balance in free-living humans". Understanding this could help design protocols for weight loss that consider all the implications of manipulating energy intakes. The authors found that:

Weight loss leads to a proportional increase in appetite resulting in eating above baseline by ∼100 kcal/day per kilogram of lost weight-an amount more than threefold larger than the corresponding energy expenditure adaptations.
While energy expenditure adaptations have often been considered the main reason for slowing of weight loss and subsequent regain, feedback control of energy intake plays an even larger role and helps explain why long-term maintenance of a reduced body weight is so difficult.

PRACTICAL TAKEAWAY - feedback control is important to consider during a period of calorie restriction as it could definitely impact the outcome of your intervention.

ALTITUDE: High Intraindividual Variability in the Response of Serum Erythropoietin to Multiple Simulated Altitude Exposures

Athletes often use exposure to altitude to help improve maximal aerobic capacity and to increase performance either at altitude or on return to sea level. However, the responses to altitude are varied and it is difficult to compare studies where different protocols are used. In this study the authors set out "clarify intraindividual variability in the serum EPO response to repeated exposures adhering to an “optimal” dose of hypoxia".

The participants were:

Physically active men and women [who] were exposed to a level of normobaric hypoxia simulating 3,000m of altitude for 12 hours on three occasions separated by 4–8 weeks.

The results showed that:

The main finding of our investigation was a high variability in the individual EPO response to repeated normobaric hypoxic exposures, despite consistent group increases.
This variability suggests that individuals who have a favorable (i.e., more robust) EPO response to acute simulated altitude on a single occasion may not have a similar response to subsequent exposures.

PRACTICAL TAKEAWAY - there is considerable variability to benefit from being exposed to simulated altitude so it's important to understand how your own body responds. The authors did suggest that at least 12 hours per day should be used as this seems to be optimal and reduce the variability between individuals and over various exposures.

CHO: Glycogen synthesis versus lipogenesis after a 500 gram carbohydrate meal in man

What happens after consuming a large meal? The authors tested the impact of a 500g meal (in the form of bread, jam, and fruit juice) on a range of physiological metrics for a period of 10 hours after the meal. The key points they shared were that:

(1) The capacity for glycogen storage in man in larger than generally believed.
(2) Fat synthesis from CHO will not exceed fat oxidation after one high-carbohydrate meal, even if it is uncommonly large.

The authors concluded that:

When a single high-carbohydrate meal is consumed, dietary CHO merely has the effect of reducing the rate of fat oxidation. These findings challenge the common perception that conversion of CHO to fat is an important pathway for the retention of dietary energy and for the accumulation of body fat.

PRACTICAL TAKEAWAY - these findings can be used in a couple of ways. Prior to a race it's possible to increase our glycogen stores significantly through eating a large portion of CHO. During regular training, it may be wary of consuming large meals if increasing the rate of fat oxidation is a desired result.

EQUIPMENT: Do Compression Garments Facilitate Muscle Recovery After Exercise?

I've shared two studies about compression before: this one suggested compression socks may reduce gastrointestinal issues, and, this one showed that compression may help when trying to achieve multiple performances in a short period of time. However, the most common use for compression is because it is thought to enhance muscle recovery following exercise.

In this meta-analysis and systematic review set out to test that hypothesis. The authors found that:

The meta-analytical evidence suggests that wearing a compression garment during or after training does not facilitate muscle recovery.
When we synthesized the data of all relevant studies, we found no effect of compression garments on strength recovery - even when factoring in exercise type and when and where the compression garment is applied.
Overall, practitioners, athletes, coaches, and therapists should reconsider compression garments as a means of reducing the harmful effects of physical exercise on muscle strength and seek alternative methods.

PRACTICAL TAKEAWAY - compression garments are probably not helping your recovery, but if there's no harm from wearing them and it makes you feel better then go ahead and keep using it.

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