Chris Beardsley

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Understanding how supaspinal and spinal CNS fatigue mechanisms work during exercise allows us to program training variables optimally . See more in this week's free Patreon article.

Non-local fatigue is closely associated with reductions in voluntary activation of the untrained limb, indicating that it is caused by central nervous system fatigue mechanisms.

@BrianCPT Fascicle length increases are closely linked to sarcomerogenesis, which increases muscle fiber force when accompanied by increases in costameres.

@SandCResearch Is there evidence for ⬆️ fascicle length being specifically beneficial for strength, injury prevention, etc.? I’d think eccentric training may help in preventing deceleration/landing injuries, but would that be due to fascicle lengthening,, neuromuscular adaptation, etc.?

Since eccentric contractions produce passive mechanical tension, they stimulate sarcomerogenesis, which we observe as increases in muscle fascicle length in humans. Isometric contractions at short or moderate muscle lengths do not.

@pitifulcmnd Strain (lengthening) leads to sarcomerogenesis in muscles, not hypertrophy.

@SandCResearch Strain leads to hypertrophy in muscle but not in tendons?

Understanding how spinal CNS fatigue works during exercise is valuable for strength training programming. See more in this week's free Patreon article.

Very few studies have found evidence for preferential sarcoplasmic hypertrophy that can be attributed to a training variable. This study is an exception. Unfortunately, a variety of training variables was used, which makes it difficult to identify which was responsible.

CNS fatigue occurs during exercise due to supraspinal and spinal mechanisms. Supraspinal is likely global in nature, while spinal is not. Differences between contralateral muscle fatigue and entirely non-local muscle fatigue may help separate the two fatigue mechanisms.

One popular idea among fitness influencers is that training blocks of light loads could increase capillary content and then permit greater muscle growth in subsequent blocks. This study shows that increasing capillarization does not facilitate hypertrophy.

Understanding how supaspinal CNS fatigue works during exercise is essential to optimal strength training programming. See more in this week's free Patreon article.

Whether myofibrils and sarcoplasm grow proportionally to one another as fiber hypertrophy occurs is controversial. Here, we can see a slight tendency for sarcoplasm to increase relative to myofibrils by an increase in mitochondrial content in untrained subjects.

When multiple muscles can contribute to a joint action (as is the case with the four elbow flexors), the activation of one muscle can inhibit the activation of the others. This may be a mechanism by which neuromechanical matching is facilitated during exercise.

Contrary to popular belief, there does not seem to be a role for increased capillarization in promoting the greater increases in relative muscular endurance that occur after light load strength training in comparison with moderate load strength training.

The psychobiological model of fatigue explains how we reach muscular failure during strength training sets. See more in this week's free Patreon article.

In line with our expectations, the rep range used during training does not affect the region where muscle growth happens within a muscle (in this case, the vastus lateralis).

Since muscle fibers produce about 1.8 times as much force eccentrically as concentrically, only 55% of the fibers need to be activated to generate the same amount of whole muscle force. This changes how we think about how hypertrophy is stimulated by strength training.

Cross-sectional analyses show that capillarization is related to [1] muscle fiber size, and also [2] muscle fiber oxidative capacity. This explains why capillaries are added around muscle fibers after both strength training and aerobic exercise.

Many fitness influencers like to criticize the principle of neuromechanical matching (although they cannot point to an alternative). See more in this week's free Patreon article.

The Nordic curl, which is a lying leg curl variation, preferentially develops the short head of the biceps femoris and the semitendinosus.

Strength is reduced after a muscle-damaging workout. However, it does not recover linearly back to baseline levels. There is an initial quick recovery phase followed by a secondary strength loss, which is attributed to the muscle-damaging effects of inflammation.