Lat pulldowns inconsistency...what's the deal?

May 23, 2013 11:03 PM

My gym has two lat pulldown machines that I use. The bar-attached-to-a-cable version is much harder than the two-handles-that-meet-in-the-middle version-- the difference in what I can lift is about 30 pounds, with the cable version being much more difficult. My trainer tells me they are equivalent, and has checked my form and says it's correct. What's the deal?
posted by blnkfrnk to Health & Fitness (8 answers total)

Is the weight visible? Check if it's moving the same distance in both machines - maybe one of the two includes a pulley, that would make it significantly easier.
posted by Dr Dracator at 11:22 PM on May 23, 2013

Sounds like the bar attached to a cable might require more control on your part to keep the bar steady? The more control you need to use, the harder it will be for you to do. For instance, being able to 'bench' 200 lbs on a bench-press machine doesn't actually mean you'll be able to lift that much weight if you're just on a bench with some weights (... as one of my good friends discovered recently). Having to stabilize and maintain control of the movement uses other muscles.

When I saw a personal trainer, he recommended free weights for this reason - you won't be able to get to such high numbers, but it'll build strength in the supporting/stabilizing muscles as well and be closer to normal movement.
posted by Lady Li at 11:56 PM on May 23, 2013 [2 favorites]

Best answer: With the bar-attached-to-the-cable version, you're probably taking a wide, overhand grip (palms facing forward) which is the equivalent of a wide-grip pull-up. With the two-handles-that-meet-in-the-middle version, you probably have a much narrower neutral grip (palms facing in). The first version isolates your lats more. The second version allows more bicep involvement.

To test this out, trying switch the two grips between the two machines to eliminate machine variance (as Dr. Dracator suggests). Assuming that doesn't alter things, try gripping the bar-attached-to-a-cable version with a narrower, underhand grip (palms facing you, the equivalent of a chin-up) and see if the weight you can pull is closer to the weight you pull with the two-handle version.
posted by zanni at 11:59 PM on May 23, 2013

zanni has the right idea that the pronated grip uses a different part of the back than the semi-supinated grip. This is the same reason that pull-ups are harder than chin-ups.
posted by esprit de l'escalier at 12:14 AM on May 24, 2013

If these are totally different machines then you need to ignore the poundage written on the weights. Cable weight machines are all over the place in terms of actual poundage you lift, at one gym I can do 160#, at another only 50#. It has to do with resistance, leverages, actual weight of the plates, blah blah blah. Track the weights you use but take the numbers with a grain of salt and just use them to show whether you're progressing or not on that particular machine. If you switch around machines then you need to go by perceived exertion if you want to compare between them.
posted by Anonymous at 12:23 AM on May 24, 2013

Agree with Schroedinger, although Zanni is also right. I tell my clients that the numbers on machines are essentially their own arbitrary scale. (This one goes to 11!) They're internally consistent, but have no connection to other machines, real life numbers/weights/measurement of mass/performance. This is another reason why it's nice to get yourself to pullups ASAP. It's your own bodyweight, that never lies.

See also:
Pat Robertson "squatting" 2000 lbs. (Leg pressing.)
posted by Telf at 12:53 AM on May 24, 2013 [1 favorite]

at one gym I can do 160#, at another only 50#

I think the OP's issue is covered by the other answers above, but I wouldn't be surprised if your 50# machine is actually labeled in kilograms, with the additional variation from differing leverage. More than 3× difference would mean some designer engineered in very wasteful mechanical advantage — material, moving, and installation costs of 100+ pounds of unnecessary iron is not cost-free! On the other hand, I don't have high regard for weight machine designers, so I admit that it is entirely possible.
posted by stopgap at 8:46 AM on May 25, 2013

I would also add that some cable machine designers are aware that you can't directly compare machines, and I've seen several models where the weights are numbered sequentially (1, 2, 3, 4, etc.) instead of by weight, even when the size of the individual iron plates gets bigger part of the way down the stack.
posted by stopgap at 8:50 AM on May 25, 2013