Can a skateboarder ride faster by holding a water bottle?

  • Context: High School 
  • Thread starter Thread starter Devin-M
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Discussion Overview

The discussion explores whether a skateboarder can achieve greater speed by holding a water bottle, considering factors such as balance, biomechanics, and the effects of added mass. Participants examine the implications of holding a bottle during skating, including potential benefits and drawbacks related to stability and performance.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • Some participants suggest that holding a water bottle could counterbalance the torque induced by ground kicks, potentially allowing for more powerful kicks without toppling.
  • Others argue that the biomechanical efficiency of the rider is complex and question how a bottle could achieve balance improvements that could not be accomplished by adjusting body posture.
  • A few participants propose that while the added mass of the bottle might not increase speed, it could help with balance and cornering, drawing analogies to animal biomechanics.
  • Some participants express skepticism about the effectiveness of a relatively light bottle compared to the rider's mass, questioning whether it could significantly impact performance.
  • There are discussions about the mechanics of balance, including the role of weight distribution and how it relates to the rider's center of mass.
  • Several participants introduce hypothetical scenarios involving pendulums and robotic arms, exploring the dynamics of balance and torque in relation to the water bottle's position.
  • One participant shares personal experience, suggesting that holding a bottle could complicate balance and performance due to asymmetry and increased difficulty in maintaining stability.

Areas of Agreement / Disagreement

Participants do not reach a consensus on whether holding a water bottle would enable a skateboarder to ride faster. Multiple competing views remain regarding the effects of added mass, balance, and biomechanics.

Contextual Notes

Discussions include various assumptions about rider posture, the complexity of biomechanical efficiency, and the relevance of weight distribution, which remain unresolved.

  • #121
Leg sweep leads to backwards tilting torque:

IMG_7819.jpeg
 
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  • #122
Devin-M said:
...pushing the body forward below center of mass causes backwards tilting torque.
Which is why your knees are bent and you're in a slight crouch whenever you're riding a board. Because skateboarding is nothing if not moving your body in relation to the CoM.

You don't need a 355g weight; you have a 70,000g weight.
 
  • #123
Devin-M said:
That’s only if the other foot has friction (standing). On a skateboard the wheels are free to roll forward under the front foot, so pushing the body forward below center of mass causes backwards tilting torque.
I'll meet you halfway with a 'maybe'. There is some friction on the wheels (especially on rough cement/concrete) that may or may not be significant.
 
  • #124
Devin-M said:
That’s only if the other foot has friction (standing). On a skateboard the wheels are free to roll forward under the front foot, so pushing the body forward below center of mass causes backwards tilting torque.
But again, unlike the leg sweep the force is not directly forward, it's forward and up.

I think at this point we're just going in circles, so I think it is best to end it.
 
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