Chris Beardsley

Figuring out how strength training works

[Chris Beardsley @SandCResearch]

My new podcast with Jake Doleschal has now launched. Available on Spotify and all other major podcasting services.

[Chris Beardsley @SandCResearch]

Figuring out whether caloric restriction reduces muscle mass is difficult when physical activity levels are normal because the reduction in bodyweight changes the number of activated fibers in activities of daily life. Immobilization studies provide an answer.

[Chris Beardsley @SandCResearch]

One curious feature of the effects of insufficient sleep is that it causes atrophy mainly in fast twitch muscle fibers but muscle damage mainly in slow twitch muscle fibers. This may provide insight into how the negative effects of sleep loss are mediated.

[Chris Beardsley @SandCResearch]

Acidosis is a metabolite-related fatigue mechanism. Exercise training can reduce the rate at which acidosis develops by a large variety of adaptations. One such adaptation is an increase in intracellular (inside the muscle fiber) buffering capacity.

[Chris Beardsley @SandCResearch]

Age affects the way in which the stimulus for some but not all peripheral adaptations works. See Patreon for the full article with citations.

[Chris Beardsley @SandCResearch]

Strength gains are surprisingly contraction mode-specific after strength training, as shown here with data from eccentric-only training and isometric training. Similar results have been recorded after concentric-only training in other studies.

[Chris Beardsley @SandCResearch]

Muscular atrophy occurs when animals and humans experience insufficient sleep. However, muscle damage is also observable, and this may provide insight into how the loss of muscle is stimulated.

[Chris Beardsley @SandCResearch]

Curiously, old people display a reduced capacity for the repeated bout effect (a group of adaptations that reduces post-workout fatigue after a single workout). This may make them more susceptible to calcium ion-related fatigue in later workouts.

[Chris Beardsley @SandCResearch]

The carbohydrate mouth rinsing literature demonstrates that supraspinal CNS fatigue is a standard feature of strength training workouts. See Patreon for the full article with citations.

[Chris Beardsley @SandCResearch]

In animal models involving eccentric training, sarcomerogenesis is greatly blunted by age. This more dramatic effect in comparison with the effects of age on fascicle length increases in humans might be explained by the greater muscle damage in the animal models.

[Chris Beardsley @SandCResearch]

Muscle loss must arise by means of either increases in muscle protein breakdown or decreases in muscle protein synthesis. This study found that sleep loss reduces muscle protein synthesis, which may explain how it can cause atrophy.

[Chris Beardsley @SandCResearch]

While older people experience less hypertrophy as a result of following a given strength training program compared to younger people, they appear to achieve similar muscle fiber type shifts. This shows that not all strength training adaptations are similarly affected by age.

[Chris Beardsley @SandCResearch]

Does fiber type affect the atrophy rate of a mechanically-unloaded muscle fiber? Probably not, if the starting muscle fiber size is controlled. Read more in the weekly free Patreon article.

[Chris Beardsley @SandCResearch]

Fascicle length increases are slowed in older people compared to in younger people. Yet, since the sarcomere addition starts to plateau early on in the younger lifters, the older lifters reach a similar point by the end of the training program.

[Chris Beardsley @SandCResearch]

When muscular atrophy is recorded in animal models of sleep loss, the glycolytic fast twitch muscle fibers are preferentially affected. Why this happens is not immediately obvious.

[Chris Beardsley @SandCResearch]

Elderly people display smaller gains in muscle fiber size as a result of following a strength training program in comparison with younger people, but the ratio of type II to type I muscle fiber hypertrophy is still maintained.

[Chris Beardsley @SandCResearch]

Static stretching increases the flexibility of the stretched and unstretched limbs. But how does that work? Read more in the weekly free Patreon article.

[Chris Beardsley @SandCResearch]

While muscle growth is certainly reduced in elderly people compared to young people, increases in tendon stiffness appear to be less markedly affected. This shows that not all strength training adaptations are similarly affected by age.

[Chris Beardsley @SandCResearch]

Lack of sleep directly produces substantial muscular atrophy in rodent models (although it is not always easy to disentangle the effects of stress and sleep loss in such cases).

[Chris Beardsley @SandCResearch]

It is well-known that elderly people experience smaller gains in muscle size as a result of following the same strength training program as younger people. Whether this problem is universal or muscle-specific, however, is less clear.

[Chris Beardsley @SandCResearch]

For at least a decade, S&C coaches argued that "intent to move quickly" was all that was necessary for speed development. That was never physiologically plausible. Read more in the free weekly Patreon article.