Question of the week. Men's Health (in 2 seperate issues) have contradicted themselves. My personal trainer said that lifting fast uses up more energy, thus burns more calories as opposed to lifting slow. Anyone else have any input?

I think it's a silly argument to be honest.

Weight lifting has very many applications for any given set of circumstances. There's a time to lift fast and a time to lift slow. It's not an either/or proposition.

I'm not even certain what you mean by lift slow and fast.

By that do you mean the actual movement speed of the weight in the eccentric and concentric portion of the rep?

Or do you mean rest time between sets?

What?

Sorry, I should have been more specific. I mean the actual time inbetween reps. Some people lift as fast as possible (may get in 8 reps in a 10-15 second duration) while others lift slow (may get in 8 reps in a 25-30 second duration).

In general, since you're not really adding any context here, it's best to control the eccentric portion of the rep and lift the concentric portion as fast as possible.

This might mean a 2-3 second eccentric and a 1 second concentric.

But I wouldn't get bogged down with the counting.

Simply be sure that you're lowering the weight in a controlled fashion and lifting the weight as fast as possible while maintaining perfect form.

It's important to note that moving a weight as quickly as you can doesn't mean the weight is actually moving fast. For instance, when I'm benching 300+ lbs, the weight is moving very slow. But I'm moving as quickly as I can.

Make sense?

Nonsense!

Anyhow you calculate it, work is applying a force over a distance. It takes a certain amount of force to move the weight from the bottom of the rep to the top. No matter how fast or slow you do it, the same amount of work (i.e. energy) is required.

Besides the fact that most people use sloppy form when they lift fast, thus negating the most benefit from the exercise, there's the fact that it takes muscle just to hold a given weight in place against the force of gravity. This is what causes slow reps to generally be more effective - you spend a lot more time suspending the weight in the air, causing your muscles to have to do a lot more "work".

I'm not a physicist or anything like that, but as I understand it, this is chemical work done inside the muscles to maintain muscle tension and keep the weight off the ground. That's the reason it's harder to do slow reps than fast reps - you don't just do the work of lifting the weight, but also the work maintaining muscle tension over a period of time.

So if anything, it's the other way around. Lifting slow uses up more energy than lifting fast. IMO, as I understand it.

I have always been told that you should do everything fairly slowly so you don't just use momentum you actually are just using your own body to move it. Dunno

You're right about that.

As noted above, it's all about lowering the weight in a controlled fashion and lifting the weight as fast as possible while maintaining perfect form.

That's one advantage of machines over free weights - they isolate the muscle group, making it harder to cheat.

But getting back to the OP, whether you burn more energy doing 8 reps in a 10-15 second duration or 8 reps in a 25-30 second duration, it doesn't matter.

Time isn't a factor in calculating work done (energy used).

Not to go too far off topic but ya, this is what I'd agree with. Interestingly enough though, I recall some research showing that walking vs. running a mile led to varying degrees of energy expenditure. I'll see if I can dig that research up.

And this is the key point. Reseach leads us to believe that there is an optimal time under tension for given goals, have them be strengh, hypertrophy or endurance related.

Well that is a VERY OLD SKOOL (outdated) view. Over a decade ago it was thought that going slow was better, but more recent theories are that lifting fast is better for muscle growth. Check out some of the studies, which refute your take on "physics".

Better still, why don't you quote your sources?

Oh, what the heck, let me add...

Lift Slow - Get Fit Fast
Slow and SuperSlow - The Fast Way to Permanent Weight Loss?
November 13, 2008

Researchers are finding that a simple change in weight training technique can have dramatic effects in building muscle. Instead of lifting a weight for 5 or 7 seconds, lift it steadily in a 10 to 14 second movement, then down in 5 to 10 seconds.

The difference is that the muscles are exhausted - brought to momentary muscle failure - in fewer repetitions (reps) - as low as 5 per set. The result - 50% more strength (muscle) built in 8-10 weeks.

Working your muscles with the slow weight lifting technique brings them to the point of momentary muscle failure - which induces the body to build more muscle.

I don't think there's anything revolutionary here.

Anybody that's monkeyed around with the weights knows you have to lift heavy to force muscle growth. And that means slower as opposed to throwing Mickey Mouse size weights around fast.

Yeah, I recall reading about it too and looked it up. It's a lot more complicated that simple Newtonian (?) physics.

It breaks down something like this. I quote:

Energy expenditure in humans is measured using an approach called 'calorimetry'. Essentially, all physiological reactions in the body that release energy is dependent on oxygen utilization. By measuring oxygen consumption (VO2), you can get a fairly accurate estimate of energy expenditure.

Researchers have measured the 'caloric stress' of many physical activities. Although different sources vary slightly, on average, a 150 lb person will burn:

--4.2 Calories per minute walking at 3 MPH
--10 Calories per minute speed walking at 5 MPH
--15 Calories per minute jogging at 6 MPH
--16.1 Calories per minute running at 8 MPH

Hence, if a 150 lb person walks at 3 MPH, it will take 20 minutes to complete a 1 mile distance. At 4.2 Calories per minute, this person will burn a total of 84 Calories:

--4.2 kcal/min x 20 min = 84 kcal

On the other hand, running the mile at 8 MPH will take about 7 and a half minutes to complete. At roughly 16.1 Calories per minute, this person will burn a total of 120.8 Calories:

--16.1 kcal/min x 7.5 min = 120.8 kcal

Not only will it take 7 and a half minutes instead of 20 to complete the same 1 mile distance, but in this example, running will burn almost one and a half times more Calories than walking.


(My question on the above research is, does body composition matter? Would a fatter person expend more energy than a muscular person?)

But the OP's question was regarding lifting - not running - fast vs slow.

I suppose the only way to answer the question definitively would be to measure VO2max both ways. I'm not aware of any such tables worked out for lifting such as the ones above for walking/running.

So until somebody can produce some studies that prove otherwise, I'll stick with my original argument that lifting "fast" doesn't burn more calories (or build more muscle either).

And my question to Gator's personal trainer would be: "So, if that's a fact, then you mean I'll burn more fat around my waist by doing sit ups fast rather than slow?"

Right, I was only thinking in terms of work. Bar distance = mile covered is why I brought it up.

I'd be interested in hearing your theories regarding fiber recruitment relative to bar speed and intensity.

And let's define what constitutes slow vs fast bar speed.

Also, are we talking about the entire rep? The eccentric only? What?

And you mention for caloric expenditure and for hypertrophy above. Are you suggesting slow reps are ideal in all contexts?

Just trying to understand your viewpoints a bit more.

I don't think that's possible.

But Gator set the parameters as 8 reps in a 10-15 second duration as fast vs 8 reps in a 25-30 second duration to mean slow.


To be truthful, I don't know what the hell we're talking about.

Again, semantics. What is slow or fast in the context of this thread?

If we're still talking rest time in between reps, then I suppose common sense prevails. If I'm hanging over a Preacher Bench with my arms in an eccentric position and 120 lbs on the bar, I'm not going to be spending too much time looking in the mirror admiring myself.

To be truthful, as I said, I don't know what we're arguing here anymore.

But to switch gears regarding "fast" vs "slow", what's your take on Blancita's assertion that lifting fast is better for muscle growth?

Haha, these aren't semantics. Rep speed is a very critical factor in training.

I'm asking you what you believe constitutes slow or fast in relation to your comments regarding lifting fast is better for caloric expenditure and hypertrophy.

I can't answer your question regarding Blancita's response either b/c I don't know what she meant by fast or slow.

We need to define stuff here.

Shit, I don't even know if we're talking about rep tempo at this point or rest periods, lol.