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Stephen Gruppetta

@stephengruppetta.com

1.7K followers 400 following 1.2K posts

Constantly looking for simple ways to explain complex things… Here you'll find: • Python • Narrative Technical Writing • Track & Field Athletics Links in the pinned post below stephengruppetta.com

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Stephen Gruppetta @stephengruppetta.com · May 19

Stuff I do…

• Python
Python articles www.thepythoncodingstack.com

The Python Coding Book amzn.to/42tJKOL

Real Python realpython.com

• Narrative technical writing
stephengruppetta.com/breaking-the-rules

• Track & Field Athletics
backonthetrack.substack.com

• Everything stephengruppetta.com

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Stephen Gruppetta @stephengruppetta.com · 12h

The last of the live information sessions is later today.

But then the course starts this Monday and there are hardly any places left.

So if you’re thinking of enrolling, don’t wait…

@realpython.com

Stephen Gruppetta @stephengruppetta.com · 22d

Interested?

Option 1: You can either come and find out more in a live info session: realpython.com/workshops/py...

Option 2: Or read about the course and book your slot here: realpython.com/live

Python for Beginners: Join One of the Info Sessions – Real Python

Join one of our live info sessions to find out more about the Python for Beginners: Code With Confidence live cohort-based course.

realpython.com

Reposted by Stephen Gruppetta

Stephen Gruppetta @stephengruppetta.com · 11d

Time to start writing the first chapter of “How to Sprint: Understanding Biomechanics”

I’m not a biomechanist.

So, I’m not writing this as an expert in the field.

…

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Reposted by Stephen Gruppetta

Stephen Gruppetta @stephengruppetta.com · 11d

It's so interesting to write articles on two different topics, for two different audiences, on publications that are so different

The Python Coding Stack is approaching 6,000 subscribers, and many articles get more views/reads than that as Google and Python newsletters feature them and all that…

…

Stephen Gruppetta @stephengruppetta.com · 11d

Sprinting — how hard can it be? You accelerate. And when you reach maximum speed, you maintain it until the finish line.

Simple, right?

But things are a bit more nuanced than that. So, put on your spikes (figuratively), and let’s get started.

backonthetrack.substack.com/p/arent-ther...

Aren't There Already Many Books On The Biomechanics of Sprinting? • Preface

Yes, but how many of them are a clear, friendly, and relaxed journey through the biomechanics of sprinting, focusing on understanding why things are the way they are?

backonthetrack.substack.com

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Reposted by Stephen Gruppetta

Real Python @realpython.com · 1d

🐍🎧 Advice on Beginning to Learn Python

What's changed about learning Python over the last few years? This week on the show, @stephengruppetta.com and Martin Breuss return to discuss the basics of learning Python.

buff.ly/cuVQHIq

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Stephen Gruppetta @stephengruppetta.com · 3d

He ran it in 46:36. Not quite the sub-40 he had aimed for, but it’s still the first time he ran 10k, so he’s reasonably pleased with it

Stephen Gruppetta @stephengruppetta.com · 18d

A personal message: My son is fundraising for The British Red Cross Society–he's planning to run a 10k in less than 40 mins.

Check out his @justgiving.bsky.social page and please donate if you can. Thank you! #JustGiving

www.justgiving.com/page/jonatha...

Jonathan's fundraiser for The British Red Cross Society

Help Jonathan Gruppetta raise money to support The British Red Cross Society

www.justgiving.com

Reposted by Stephen Gruppetta

Stephen Gruppetta @stephengruppetta.com · 8d

More importantly, do you like the stick figures I crafted for this series?

I’ll be using them throughout.

And yes, the arms are missing deliberately.

Stephen Gruppetta @stephengruppetta.com · 9d

It’s time to sprint. Where do you start?

You start from standing still. That’s how all sprinting starts. Your velocity is zero. You need to increase your velocity. You need to accelerate.

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Stephen Gruppetta @stephengruppetta.com · 8d

More importantly, do you like the stick figures I crafted for this series?

I’ll be using them throughout.

And yes, the arms are missing deliberately.

Stephen Gruppetta @stephengruppetta.com · 9d

It’s time to sprint. Where do you start?

You start from standing still. That’s how all sprinting starts. Your velocity is zero. You need to increase your velocity. You need to accelerate.

1/n

Reposted by Stephen Gruppetta

Stephen Gruppetta @stephengruppetta.com · 9d

It’s time to sprint. Where do you start?

You start from standing still. That’s how all sprinting starts. Your velocity is zero. You need to increase your velocity. You need to accelerate.

1/n

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Reposted by Stephen Gruppetta

teachmepython.bsky.social @teachmepython.bsky.social · 9d

I don't use lambdas very often, but they are very handy in #Python when you use the built-in sorted() function

By using a lambda, you can do some cool advanced sorting! 🐍🔥

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Reposted by Stephen Gruppetta

Stephen Gruppetta @stephengruppetta.com · 10d

I think you may find this interesting even if you don’t care about sprinting. Here’s the first part of How to Sprint: Understanding Biomechanics

…and as you’d expect, I wrote it in my own casual and narrative style.

backonthetrack.substack.com/p/1-its-time...

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Stephen Gruppetta @stephengruppetta.com · 9d

You’ll get back to the “pulling the ground” misconception later in this chapter.

Let’s find another way to start moving forward.

Continue reading at backonthetrack.substack.com/p/1-its-time...

/end

1. It’s Time to Start Sprinting • Force, Acceleration, and Maximum Velocity

This post includes the introduction to Chapter 1 and subsection 1.1 Acceleration

backonthetrack.substack.com

Stephen Gruppetta @stephengruppetta.com · 9d

“Ah, but Stephen, in addition to pushing down into the ground with my feet, I can also pull the ground behind me with my feet–my hamstring does most of the work in this situation. Surely, that’s how I can start moving forward!”

No.

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Stephen Gruppetta @stephengruppetta.com · 9d

But you’ve been walking and running daily since your toddler years. This means we’re still missing something.

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Stephen Gruppetta @stephengruppetta.com · 9d

So, that’s it. You’re stuck. You can jump upwards, but you can’t move forward! It’s like when you’re playing a video game and you can use the up arrow to make your character jump, but you can’t use the right or left arrows to make it move sideways!

18/n

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Stephen Gruppetta @stephengruppetta.com · 9d

Stand up straight and imagine a straight line connecting your feet to this point behind your belly button–your centre of mass. It’s a vertical line, perpendicular to the ground. This is the only direction you can apply force to the ground.

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Stephen Gruppetta @stephengruppetta.com · 9d

You’d place this imaginary sphere roughly at the location of your belly button, somewhere in the middle of your abdomen between your tummy and your back. This point is the body’s centre of mass.

16/n

Stephen Gruppetta @stephengruppetta.com · 9d

You wouldn’t place it on the tip of your small finger in an outstretched arm. Most certainly not. And you wouldn’t place this sphere at the top of your head, either. You’d topple over instantly if your centre of mass were at the top of your head.

15/n

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Stephen Gruppetta @stephengruppetta.com · 9d

Where would you place this sphere to best represent your body?

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Stephen Gruppetta @stephengruppetta.com · 9d

Let’s avoid a technical discussion of the concept of centre of mass. Instead, let’s focus on an intuitive understanding of the centre of mass, which is all you need! Imagine you had to place all of your body’s mass into a small sphere. It will be a small, heavy sphere.

13/n

Stephen Gruppetta @stephengruppetta.com · 9d

You can only apply force in the direction of the straight line connecting your centre of mass to the point of contact with the ground–your foot (or more accurately, as you’ll see soon, the front part of your foot). This last sentence will make more sense shortly, I promise.

12/n

Stephen Gruppetta @stephengruppetta.com · 9d

You can jump vertically upwards if you want. But you’re trying to run forwards!

11/n

Stephen Gruppetta @stephengruppetta.com · 9d

And since your feet are directly below your body when you’re standing upright, you can only apply force directly downwards into the ground. Therefore, the ground can only produce a force on your body that’s vertically upwards.

10/n

Stephen Gruppetta @stephengruppetta.com · 9d

Why is this a problem? You can produce force with several muscles in your body, mainly in your legs. But you can only apply these forces to the ground through your feet since they’re the only part of your body in contact with the ground.

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Stephen Gruppetta @stephengruppetta.com · 9d

Later, when you start sprinting, only one foot will be in contact with the ground–or none if you’re flying through the air!

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Stephen Gruppetta @stephengruppetta.com · 9d

Feet

But there’s a problem. The only part of your body in contact with the ground is your foot. If you’re still standing stationary waiting to start running, then both feet are touching the ground.

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