Energy/calories and average force

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Discussion Overview

The discussion revolves around the relationship between energy expenditure, calories burned, and average force during physical activities, specifically in the context of bench pressing weights. Participants explore how speed and repetitions affect energy consumption and metabolic energy use during exercise.

Discussion Character

  • Debate/contested

Main Points Raised

  • Wayne argues that performing bench presses at a faster rate (6 times in 12 seconds) results in higher energy/calorie expenditure compared to performing the same number of presses more slowly (1 time in 12 seconds).
  • Another participant questions Wayne's reference to "someone" who claims that average force remains the same and thus energy/calories burned would also be the same.
  • A participant asserts that more calories are burned during the six presses in the first option due to the higher metabolic energy used by the body, which exceeds the useful work performed.
  • It is noted that during bench pressing, no net work is done on the weights since the work done by the arms on the weights during the up press is countered by the work done by the weights on the arms during the down press, leading to metabolic energy being expended in both phases.

Areas of Agreement / Disagreement

Participants express differing views on the relationship between speed, repetitions, and energy expenditure. There is no consensus on the claims made by "someone" regarding average force and energy use.

Contextual Notes

Participants highlight the complexity of equating metabolic energy consumption with useful work output, noting that significant energy is often expended after exercise due to increased metabolic rates.

waynexk8
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Energy/calories and average force.

If you look in all Nutrition books and sites, you use/burn far far far more energy/calories when doing the same activity twice as fast. However someone says as the average force is the same in the below example, that you use the same energy/calories, I say this is not true, as the example 1 below is traveling faster and for more distance using more power. {work energy}

1,
Bench press 80 pounds or 80% of your RM {repetition maximum} 6 times up and 6 times down, 1 second up and 1 second down = 12 seconds in all. 1m each way = 12m in all.

2,
Bench press 80 pounds or 80% of your RM {repetition maximum} 1 time up and 1 time down, 6 seconds up and 6 second6 down = 12 seconds in all. 1m each way = 2m in all.

Wayne
 
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someone says as the average force is the same in the below example, that you use the same energy/calories
Reference "someone" please!
 
Hi Wayne, I would have preferred to see what exactly "someone" said so I knew exactly what case we were discussing, but let me try anyway.

First off let me say that you will burn more calories doing the 6 presses of option "1".

Where I'm guessing that you are running into conceptual problems is in trying to equate energy consumption of the human body to the amount of useful output work. Typically with exercise the amount of metabolic energy used by the body is far greater than the amount of useful work performed. In fact a significant proportion of the extra (above basal metabolic) energy consumed during exercise often occurs after the exercise session has completed, due to the increased metabolic rate induced by the exercise! (which can last for quite a long time after the exercise session is over).
 
Last edited:
As for the bench press repetitions, there is actually no net work done in either case. On the up press your arms are doing work on the weights and on the down press the weights are doing work on your arms. Of course your arms are not able to "regeneratively brake", so you actually use metabolic energy on both the up press and the down press. In the end however it's all wasted energy and no net work is done on the weights.
 
Hi there uart, thanks for your time and answer, I will try and get the person to tell me exactely what he's means.

Wayne
 

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