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2/1/2023 Literature Review

The Ergogenic Effect of Caffeine

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There is good to strong evidence to support caffeine consumption to improve exercise based performance. Along with creatine it is one of the most studied and proven supplements in men and women. Typical recommendations are doses of 3-6 mg per kg of body weight. Which can be a large range. For example, for someone who is 200 lbs this can be from 270-550 mg.

Habitual caffeine intake may blunt some responses in certain individuals and almost 33% of people might not be good responders to caffeine for ergogenic effects. Also largely most people tend to over utilize caffeine to make up for things like poor sleep habits.

While it appears that the effects of caffeine can be blunted by regular use for greater than 20 days in a row it does not appear that it has no effect. Especially for those who tend to use caffeine on the lower end of the 3-6 mg per kg range. While this seems to be the case it appears across research that acute doses of caffeine, especially near the higher end of the ranges still elicit positive effects on performance. Additionally, higher doses of caffeine >6 mg per kg may not be needed to produce effects. As it is often seen at doses higher than this significantly increases the chances of experiencing a negative effect like insomnia, nausea, anxiety and restlessness.

Habitual caffeine users at this time likely should not exaggerate pre exercise doses in hopes of achieving a larger effect. Or more significantly “feeling” a larger effect. As it may be that someone is seeking the “first high” effect, or a feeling they subjectively experienced early on in regular caffeine use.

This study also reviewed caffeine withdrawal with most studies showing no changes with withdrawal of 24-96 hours. Although it may take longer to completely withdrawal and become naïve to caffeine again. But withdrawal doesn't seem to be necessary to continue to experience benefits from caffeine.

Further, there appears to be little evidence looking at the effects of caffeine combined with ingredients found in many pre workouts and or energy drinks. At this time we cannot yet make strong comments about this area.

Carvalho A, Marticorena FM, Grecco BH, Barreto G, Saunders B. Can I Have My Coffee and Drink It? A Systematic Review and Meta-analysis to Determine Whether Habitual Caffeine Consumption Affects the Ergogenic Effect of Caffeine. Sports Med. 2022 Sep;52(9):2209-2220. doi: 10.1007/s40279-022-01685-0. Epub 2022 May 10. PMID: 35536449.

Weightlifting and Self-Esteem

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We all have seen the memes and jokes about going to the gym to fight our demons or going to the gym giving us body dysmorphia. But what does some data say about this?

This study was done in Turkey so it may not directly compared to other regions or countries, but found some interesting things. They looked at how participation in sports impacted self efficacy and self esteem.

In this study self-efficacy is considered self judgment and or belief that someone can do something. Self-esteem is an individuals thoughts about their own personality and or thoughts.

In this study the most preferred sports by participants included bodybuilding, soccer, walking and swimming. On average participants were 23 years of age and split fairly evenly between men and women.

The authors suggested that there appears to be a positive correlation between participation in the sports that participants self selected and positive self esteem. In general being sedentary across the lifespan is common and causes many negative effects on mental and physical health.

Exercise habits seem to have a positive impact on self esteem, body awareness, and self efficacy. It is important to consider someone's personal preferences as well as participation in activity that is enjoyed would likely have more of a positive impact. Overall due to a number of factors including effects seen with exercise, self fulfillment, and socialization bodybuilding, at least in this population, has a positive effect on psychological well being.

Tikac G, Unal A, Altug F. Regular exercise improves the levels of self-efficacy, self-esteem and body awareness of young adults. J Sports Med Phys Fitness. 2022 Jan;62(1):157-161. doi: 10.23736/S0022-4707.21.12143-7. Epub 2021 Feb 8. PMID: 33555673.

Effects of Periodization on Strength and Muscle Hypertrophy

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Many resistance training variables can be manipulated to achieve the most desirable outcomes from a program including strength and hypertrophy. The planned manipulation of training variables over time is known as periodization. For a long period of time has been based on the principles with general adaptation syndrome, where training can be planned in a way that overtraining, and injury can mostly be avoided and performance can be maximized.

Types of periodization include linear, reverse linear, undulating and block periodization. Linear periodization is when there are increasing intensities over time and decreases in volume. Reverse linear periodization is when intensity reduces but volume decreases. Undulating periodization (also known as non linear periodization) has more frequent changes to volume and intensity and sub divided into Daily undulating periodization and weekly undulating periodization. As the names imply there are either daily or weekly changes to intensity, volume, exercise selection etc. Block periodization includes training being divided into several distinct phases (blocks) where that block might focus on a certain adaptation or goal.

At this time it appears that periodized training results in larger strength gains than non periodized training although effect sizes were small between groups. However there was no significant difference for hypertrophy in periodized and non periodized training programs. It appears that the changes seen between strength and hypertrophy programs is largely neurological. There may be a difference in coordination and motor unit recruitment seen with periodized programs for strength training. This may be due to changes in training variables which can improve motor learning. This also appears to be the case across trained and untrained individuals.

It does appear that in untrained individuals periodization may not be as important as in trained individuals. In trained individuals undulating periodization appeared to provided superior benefits compared to other forms of periodization. Which may mean trained individuals benefit more from more frequent changes in training variables. However, it is important to know that forms of training periodization are not mutually exclusive and can be combined.

It seems that changes to intensity and volume daily and or weekly may help maximal strength adaptations based on the current data. It is important to note however that authors discuss that weaknesses of this study include drastically different variable across studies making it difficult to say which factors within a model should be manipulated and in what manner. Further, there is a large amount of between and within individual differences, meaning that while we can use science as a starting point, adjusting variables that have the most support is still important to see the best individual response.

When volume is equated it does not appear periodization is as important for hypertrophy, however periodization does seem to have more of an effect on maximal strength. Undulating periodization for strength gains seems better than linear and non periodized programs at this time, specifically in trained individuals.

Moesgaard L, Beck MM, Christiansen L, Aagaard P, Lundbye-Jensen J. Effects of Periodization on Strength and Muscle Hypertrophy in Volume-Equated Resistance Training Programs: A Systematic Review and Meta-analysis. Sports Med. 2022 Jul;52(7):1647-1666. doi: 10.1007/s40279-021-01636-1. Epub 2022 Jan 19. PMID: 35044672.

Training Frequency

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Principles of progressive overload can be achieved in a number of ways. For example adding to the training load, adding to the number of sets or reps performed, or increasing how often a movement is performed. For example, if you go from training squats 1x a week to 2x a week.

Once the absolute load is no longer able to be progressed what do we do? Ideally you could keep getting stronger forever but we know this is not the case. Typically, most people will perform more reps with a given weight, perform more sets or increase the number of times a muscle group is trained. As for hypertrophy increases in volume are in general correlated with increases in accumulation of muscle mass.

The authors suggest that muscle growth is dependent on fatigue to fully activate high threshold motor units, but as covered previously in our newsletter, it appears that this is only required with low load training (less than 60% 1RM). They cite that many bodybuilders perform 4 sets of 4 exercises within a session equating to 16 sets per session. Which seems to be based on older studies possibly looking at enhanced bodybuilders. As new research may suggest it is more productive to perform less sets per session and divide the volume between 2-3 sessions.

There is a point at which there is diminishing returns within the session which they cite as possibly being 4 sets. However, some work by James Kreiger and Meno Hennselman with internal meta analysis suggest that the cap per session may be between 6-13 sets per session. This may vary individual to individual but at some point muscle protein breakdown will be surpassed by breakdown within a set time period. Further, while this paper uses muscle protein synthesis research largely there are other triggers that elicit muscular growth due to the complex nature of muscle hypertrophy when we get into minute physiology.

The case for higher frequencies however still exists for many reasons. In some individuals maximum protein takes 72 hours to be “reset” in other words its stimulated as much as it can be in that time period and cannot be overridden. However in trained individuals this window can be as short as 8 hours and most commonly cited as 24-48 hours.

In theory the greater frequency of stimulus could elicit positive adaptations more often. So long as the volume of exercises performed is able to recovered from. The increase in frequency could mean more time spent in net positive muscle protein synthesis (just to name one factor). Some literature suggests positives towards training 2-3x per week in particular over other frequencies, however the case can be made for more/less frequent training depending on many factors.

If someone is having difficulty recovering from training or all factors are in line but are still not seeing growth, one may consider increasing their training frequency to benefit hypertrophy. Typically this is done to facilitate greater volume on a given movement/muscle group.

Dankel SJ, Mattocks KT, Jessee MB, Buckner SL, Mouser JG, Counts BR, Laurentino GC, Loenneke JP. Frequency: The Overlooked Resistance Training Variable for Inducing Muscle Hypertrophy? Sports Med. 2017 May;47(5):799-805. doi: 10.1007/s40279-016-0640-8. PMID: 27752983.

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