Matheus Daros Pinto

NEW: Pre-print of our new meta-analysis now available. Using data from 78 studies and over 120,000 males and females, we found that the muscle strength-to-body mass ratio is generally greater in males than females. Thus, dividing muscle strength by body mass does not mathematically eliminate the male strength advantage. This is likely because factors other than body mass contribute to the sex difference in muscle strength and because the relationship between muscle strength and body mass is not linear, which is what is assumed when dividing muscle strength by body mass (i.e., ratio scaling). Further, we found that the sex difference in the strength-to-body mass ratio is smallest in children and largest in adults, and it is greater in upper- than lower-limb muscles. Note: This paper is currently undergoing peer review at a journal. Some contents of the pre-print will change after we receive feedback from reviewers. How to Support Our Work: This research was conducted independently, without institutional backing or external funding. If you value this work and would like to support it, please visit the GoFundMe link in the comments or in my pinned tweet. Thank you for your support. Co-author: @MatheusdPinto

🧵NEW: Our latest paper is a meta-analysis of sex differences in upper- and lower-limb strength in kids aged 5-17 years old (3,497 boys; 3,137 girls). Before, during, and after puberty, boys are stronger than girls on average. The sex difference in muscle strength is ~10% in 5–10-year-olds and increases to ∼40% in 14–17-year-olds. Throughout development, the sex difference in strength tends to be more pronounced in upper- than lower-limb muscles. Co-author: @MatheusdPinto

@DustinOranchuk @Retlouping I think that in itself is already hinting they will display different fibre/ fascicle behaviours.. Yep, I think that'll do and maybe we just to remind they're isometric at the joint level - out of curiosity, which muscles/ joints are these commonly performed?

@MatheusdPinto @Retlouping Well, they are clearly different from neural and metabolic perpectives. Do you think a different wording (e.g., 'isometric activities', 'isometric types') might be better? At least for now.

Are there two forms of isometric muscle action? Results of the experimental study support a distinction between a holding and a pushing isometric muscle function pmc.ncbi.nlm.nih.gov/articles/PMC54… “there are probably two forms of isometric muscle action. “

@DustinOranchuk @Retlouping @DustinOranchuk, thanks for clarifying. I'd think this is the first step before suggesting there are two 'forms of isometric muscle actions'

@Retlouping @MatheusdPinto @MatheusdPinto, none of the studies included in the review used ultrasound or any other method to describe what is happening with the fascicles etc. I guess that PIMA and HIMA will be very similar, but it would be interesting and probably not overly tricky to test this!

@Retlouping Do you know what the muscles and fascicles are doing during these 'isometric' contractions? Are they moving? Do they move differently? You are calling them "isometric muscle actions", so my interpretation is that the fascicles and the muscle remain at fixed length.

@MatheusdPinto Not sure what you are asking?

@ricardoNOmesqui @ActivateGlutes @jacksonfyfe @MathewPiasecki Well, yeah, I don't really know but... don't SCI patients face apoptosis of spinal motor neurones? So perhaps in extreme cases of disuse we might lose motor units regardless of age... but in any case, movement (and particularly lifting heavy weights) seems the way to go...

@MatheusdPinto @ActivateGlutes @jacksonfyfe @MathewPiasecki That is a great question. I don't think we lose motor units simply because of disuse, do we? If I break my arm and don't move it for an extended period, will I lose motor units? But we seem to inevitably lose motor units after our sixties (though longitudinal data is lacking)

With ageing, not all muscle fibres deteriorate equally. Those critical for higher-intensity activity suffer most: The larger and faster type II muscle fibres. Despite being recreationally active (but not strength training), older men aged 69 on average had: - 32% smaller type II fibres - 53% more type I (slow) fibres - 18-fold more grouped type I fibres (a sign of type II fibre loss) All compared to younger males aged 22 on average. The only thing known to counter these age-related effects in type II fibres? Resistance training. The muscles of 73 year-old masters strength athletes resembled those of people younger than 30. Compared to older controls they had: - 49% more type II fibres - 82% more grouped type I fibres - Virtually no atrophic (very small) fibres Strength training isn’t just about staying strong - it’s the only way to preserve type II muscle fibres as you age.

@ActivateGlutes @ricardoNOmesqui @jacksonfyfe @MathewPiasecki So is that an age effect or disuse effect or a combination of both?

@MatheusdPinto @ricardoNOmesqui @jacksonfyfe @MathewPiasecki Some or later (likely later for these muscles) there will be loss... hopefully much later

@ricardoNOmesqui @jacksonfyfe @MathewPiasecki Nice paper, I wasn't aware. I agree, but could that be muscle specific (and assocaited to training requirements)? In Figure 1, the Master's athlete has much bigger gastroc and soleus than the young and old representations (and myself haha). Would you expect MU loss on them?

@jacksonfyfe Cool stuff! But even if you use it, you may end up losing it. Even masters athletes might unfortunately not be spared from motor unit loss after the seventh decade of life. @MathewPiasecki et al: physoc.onlinelibrary.wiley.com/doi/10.14814/p…

Nice to see people contemplating the results of our recent meta-analysis on eccentric vs concentric muscle strength. @JamesSteeleII @MatheusdPinto

@JamesLNuzzo Not suprising....

"Chronic static stretching exercises result in an overall unclear effect on skeletal muscle hypertrophy."

@JamesSteeleII @AJThurston @AllenDowney @jonaslindeloev Would also be keen to see them. Were you teaching R coding or are they stats concepts? Or perhaps a mix of both?

What if we taught #psychstats showing there is only one test, per @AllenDowney: allendowney.blogspot.com/2011/05/there-… Using the {infer} #rstats package: infer.tidymodels.org/articles/infer… Or at least leveraging #dataviz to illustrate its all OLS like @jonaslindeloev’s post here: lindeloev.github.io/tests-as-linea…

Even small doses of resistance training can have big benefits. Some updated evidence on minimal dose resistance training approaches, including: “Weekend warrior”: a single weekly resistance training session “Single-set resistance training”: one set of multiple exercises, multiple days per week “Resistance exercise snacking”: brief bouts performed once or multiple times daily “Practising the test”: one maximal repetition in one or more sets, multiple days per week “Eccentric minimal dose”: low weekly volumes of submaximal or maximal eccentric-only repetitions All can improve muscle strength - and at lower doses than current recommended guidelines. Nice work from @JamesLNuzzo and co. link.springer.com/article/10.100…

NEW: Our overview of minimal dose resistance exercise is now available @SportsMedicineJ #OpenAccess. Co-author: @MatheusdPinto link.springer.com/article/10.100…

@JamesSteeleII Can you share please mate?

@DrDeSouzaEO @AusHumanBiology @JBiomech @TonyBlazevich Obrigado Edu!

@MatheusdPinto @AusHumanBiology @JBiomech @TonyBlazevich This is awesome @MatheusdPinto! Parabéns! Maior orgulho!

On this day last year, I was awarded the 1st prize for my presentation at the @AusHumanBiology conference. Almost a year later, the paper is now published open access in the @JBiomech. Thank you reviewers for valuable feedback. Link: sciencedirect.com/science/articl… @TonyBlazevich

@Mohamed67199696 @peteburridge @gstevens21 If you haven't already shared, here is our paper discussing multiple devices for eccentric training. link.springer.com/article/10.100…

@peteburridge @gstevens21 HELLO I am Mohamed from Egypt. I am interested in eccentric training, especially for football players. I am in the process of doing a study on this type. Could you please help me with more forms of training and studies?

Eccentric training IMO is one of the best ways to develop strength & hypertrophy ↗️TUT ↗️Supra-maximal forces ↗️Motor unit recruitment ↗️Satellite cell activation There are lots of ➕training adaptations Here’s how to use one of the most potent eccentric training strategies…

NEW: We updated the REPS-%1RM table that has been printed in the NSCA textbook for ~20 years One table for leg press One table for bench press One table for all other exercises Published #OpenAccess @SportsMedicineJ Authors:@MatheusdPinto @JamesSteeleII link.springer.com/article/10.100…

Now in-print: Our overview of muscle fatigue (acute strength loss) during max eccentric vs concentric resistance exercise. The quadriceps appear more "protected" against muscle fatigue and damage from max eccentrics than arms muscles. @MatheusdPinto onlinelibrary.wiley.com/doi/epdf/10.11…