OK, let's start out with the conclusion Sunset Boulevard style and then I'll explain how I got there. The maximum base GURPS ST for a given human body weight is the cube root of the character's body weight times 2.6. The maximum GURPS lifting ST is equal to the cube root of a character's body weight times 3.2. So a 125 lb power lifter who represents the maximum in human muscular development could have a GURPS ST of 13 and a GURPS lifting ST of 16 (representing +3 Lifting ST.) Total cost would be 39 points in 4e - 30 points for ST 13 and another 9 points for +3 Lifting ST. So how did I arrive at these numbers? With the following assumptions:
1. It's been stated by Kromm that to calculate an animal's GURPS ST, take the cube root of weight in pounds and multiply by 2, e.g. a 125 lb creature should have a ST of 10. This suggests that ST is a dervied attribute of mass. As a rule, secondary attributes such as Striking ST or of Lifting ST shouldn't vary more than 30% from base ST. Following that logic, assuming normal terrestial biology a GURPS character's ST shouldn't be more than 30% higher than that predicted by mass. Thus a 125 lb character would have a base ST of 10 (cube root of 125 times 2) and a maximum ST of 13 (30% greater than predicted.) That's where I get the 2.6 mulitiplier.
2. GURPS ST represents a wide range of ability - carrying capacity, lifting ability, ability to inflict physical damage and structural capacity for physical damage. Weight lifters are likely to be specialized, with Lifting ST on top of normal ST. This goes 30% beyond base ST - thus again our 125lb character representing peak muscular development can have +3 Lifting ST on top of his 13 ST. That's where I get "cube root of a character's body weight times 3.2."
3. I'm using world records for the clean and jerk and the snatch from the International Weightlifting Federation as a base of comparison. I'm estimating that the basic level for the Snatch is equal to Base Load times 5, and the Clean and Jerk is equal to Base Load time 6. How did I get these numbers? Well, the world records for the Clean & Jerk are about 20% greater than the records for the Snatch, so that gave me the 5:6 ratio. In addition, both Clean and Jerk and Snatch are less than the world records (near as I can tell) for the Bench Press. I estimate the Bench Press as being around BLx7 or BLx8 - about 140 to 160 lbs for a ST 10 character. Putting Snatch at BLx5 and Clean&Jerk at BLx6 seems to line up well with Bench Press.
4. In a realistic campaign, bonus from Extra Effort and Lifting skill ought to be capped. As written, Lifting skill allows a +5% bonus for every point which you roll under skill - e.g., if you have a skill of 13 and roll a 9 you get a 20% bonus. In the real world, maximum lift doesn't vary that much for a person, so I'd be inclined to cap it at +25% with a small bonus for exceptional effort (say +1% for every additional point the character makes the roll by.)
OK, so let's take these assumptions and plug them in and measure against reality. Take a 152 lb character. Base on these assumptions, he could have a peak ST of 13.9 and a peak lifting ST of 17.1 (I'm using fractions to aid the reality check.) That gives a BL of 58, a base Snatch of 290 and a Clean & Jerk of 348. Allowing for a +25% boost from extra effort and Lifting skill, that's a Snatch of 362 and a Clean & Jerk of 435. By comparison, the world records for the 152 lb class men's competitors are 363 lbs for the Snatch and 433 for the Clean & Jerk. A reasonably close approximation of reality.
So where does the 18 come in? Well, as I said, peak ST for a given weight for a realistic human character is equal to the cube root of weight times 2.6. Thus, the minimum weight for a human character of a given ST is equal to (ST/2.6) cubed in lbs, or ST cubed divided by 2.6 cubed. 2.6 cubed is about 17.8 or 18. So based on these assumptions, a realistic human character should weigh at least ((ST cubed)/18) pounds.
Of course the assumptions could be tweaked - for example, disallow Lifting ST but allow a higher boost from Extra Effort and Lifting skill. I realize this little discussion isn't really necessary for the game but I think it adds a bit of realism.
As an incidental note, the mass to strength ratio for the world records tracks a 2/3 power relation pretty closely in case anyone ever doubted GURPS Gulliver.
Addendum: Female strength
I used the world records for men when calculating these numbers. The records for women are for a little over 3/4 those of men, for the same body weight (i.e., 125 lb man vs 125 lb woman.) However GURPS ST covers a much wider scope of ability than just weight lifting. For female human characters, I suggest peak ST equal to cube root of weight times 2.4 and peak lifting ST equal to cube root of weight times 2.8 for Lifting ST. Using the assumptions above, a 128 lb woman would have a maximum ST of 12.1 and maximum Lifting ST of 14.1. By comparison, Sora from GURPS Basic Characters weighs 130 lbs and has a ST of 12. This gives weight lifting numbers pretty close to the world records. Realistically, a high ST female character would be built like Serena Williams, not Kate Moss. None of this applies to cinematic campaigns or campaigns with paranormal abilities. Ignore these guidelines if you have characters named Buffy Summers or Diana Princess running around.
- DW
Strength at 1000 lbs.?
Sun, 2007-01-07 09:47 — K. David Ladage (not verified)You wrote: It's been stated by Kromm that to calculate an animal's GURPS ST, take the cube root of weight in pounds and multiply by 2, e.g. a 1,000 lb creature should have a ST of 10.
I think that should be: e.g. a 1,000 lb creature should have a ST of 20.
Lifting Skill
Sun, 2007-01-07 09:43 — K. David Ladage (not verified)I have read in some areas that lifting skill, at +5% per point of success is *grossly* unrealistic. Not being into weight-lifting, I cannot say.
But the most common suggestion I have heard is to give a +5% bonus on a successful roll. Not +5% per point of success, but a +5% on a success. Period.
Re Lifting Skill
Sun, 2007-01-07 21:34 — tboneI agree. I have +5% per 2 levels of success as a rule in GULLIVER, and attempted to bring something like that to a new non-GURPS project, but was convinced by my helpful collaborators that it's far too generous.
So, for that project I'll be implementing a Lifting skill that works as follows: a) Adds a small bonus to lift in general (for optimal technique); b) Considerably aids rolls to resist injury in extreme lifting; and c) Directly affects certain special "moves" that go beyond plain muscle contraction.
As an example of the latter, a "clean & jerk" lets you lift more above your head than your arms alone could manage, as you quickly "slip under" the weight to successfully extend and lock your arms, finishing the lift through leg power. It's a tricky move that considerably boosts your lift, but calls for real skill.
I think this toned-down treatment of Lifting skill is much more realistic, yet is interesting and keeps the skill vital for competition purposes.
Re: Eighteen, or maximum human strength
Thu, 2006-11-30 01:24 — tboneAhoy, DW! Lots there to chew on; sorry, RL kept me from biting in these couple of days.
Sifting through the numbered paragaphs:
1. Things look good. Though re "This suggests that ST is a dervied attribute of mass", I would prefer to say that it simply suggests the two have the correlation noted, not that ST is a derived attribute of mass. Or do I miss a key point there?
2. So far so good... That is, I can't say that the assumption about how much extra Lifting ST a weightlifter can reasonably add is a "correct" assumption, but it's not jumping out as objectionable either. And any assumption of the "neither good nor bad" persuasion starts falling on the side of "good" when backed by a reasonable-sounding rationale like yours. : ) So forging onward:
3. Man, it's always hard to turn the hodge-podge of weight-lift info out there into game bits, but that never stops us from trying... I too have some Snatch vs Clean & Jerk vs Double-Spasm Quadra Heave ratios that I came up with. Let me dig those up, and see whether they match yours.
4. Glad to see that you're considering both Lifting and Extra Effort. And I agree: the RAW allow bonuses to really pile up, so for a realistic consideration, it's best to choose some flat +X% as the probable standard bonus for record-setting lifts. Until we know better, the arbitrary +25% is as good as any other shot in the dark.
And on to the example: yes, your assumptions do work out nicely for that example.
The upshot of the post, as I see it, is: we now have a nice formula setting a minimum reasonable weight for a given lifting ability in humans, based on some defensible assumptions.
But I'm missing something regarding the main point: the max ST of 18. Is that just working backward from the top weightlifting records? Or are you drawing this conclusion of 18 from human body weight? Something's not registering with me.
Maximum human strength
Thu, 2006-11-30 12:28 — Esteemed Visitor 2 (not verified)1. Things look good. Though re "This suggests that ST is a dervied attribute of mass", I would prefer to say that it simply suggests the two have the correlation noted, not that ST is a derived attribute of mass. Or do I miss a key point there?
Well, realistically strength is going to be limited by mass - given peak muscular development a 150 lb man will be stronger than a 125 lb man. In a sense, the default value of ST should be based on useful body mass. The 30% variation was arbitrary - since GURPS allows secondary characteristics to vary by +/- 30%, I decided to try a maximum of +30% over Strength predicted by body weight.
2. So far so good... That is, I can't say that the assumption about how much extra Lifting ST a weightlifter can reasonably add is a "correct" assumption, but it's not jumping out as objectionable either. And any assumption of the "neither good nor bad" persuasion starts falling on the side of "good" when backed by a reasonable-sounding rationale like yours. : ) So forging onward:
3. Man, it's always hard to turn the hodge-podge of weight-lift info out there into game bits, but that never stops us from trying... I too have some Snatch vs Clean & Jerk vs Double-Spasm Quadra Heave ratios that I came up with. Let me dig those up, and see whether they match yours.
As I said, they were fairly arbitrary. I knew that based on world records a. they should both be less than Bench Press and b. the two lifts should have a 5 to 6 ratio. I then guesstimated Bench Press at BL x7 or 8 simply because it sounded right.
4. Glad to see that you're considering both Lifting and Extra Effort. And I agree: the RAW allow bonuses to really pile up, so for a realistic consideration, it's best to choose some flat +X% as the probable standard bonus for record-setting lifts. Until we know better, the arbitrary +25% is as good as any other shot in the dark.
And on to the example: yes, your assumptions do work out nicely for that example.
Well, yes but I did tweak it a little to fit. The strength involved in a Clean & Jerk or Snatch is more narrowly focused than Lifting ST so you might instead increase the maximum from Lifting skill to say +50% and maximum Lifting ST to 2.9 times cube root of weight. The assumptions can be changed - I just thought it amusing if you started with the assumption that ST was a secondary characteristic of mass and plugged in these other assumptions maximum lift was pretty close to the world record
The upshot of the post, as I see it, is: we now have a nice formula setting a minimum reasonable weight for a given lifting ability in humans, based on some defensible assumptions.
But I'm missing something regarding the main point: the max ST of 18. Is that just working backward from the top weightlifting records? Or are you drawing this conclusion of 18 from human body weight? Something's not registering with me.
My fault for being a little too cute. The "18" is actually from the formula for determining the minimum body weight to support a given ST - cube the ST and divide by 18. I don't make any assumptions about maximum overall human ST - just maximum for a given weight. I think the highest record required a Lifting ST of 21 or so based on this model. Incidentally the NY Times had an article recently about the 345 lb winner of the world's strongest man contest - a firefighter by trade. Based on my model, a 345 lb man (assuming he's not fat) would have a base ST of 14 for mass only, a maximum ST of 18 and a maximum lifting ST of 22. So perhaps 18 is the maximum for base ST.
What I like about this also is that if you combine it with the rules for negative encumbrance there's a strong incentive to make agile characters like acrobats and climbers small wiry guys. Now I just need to write up positive and negative encumbrance as meta-traits and add rules for incorporating mass into grappling.
-DW
Re Maximum human strength
Wed, 2006-12-06 13:17 — tbone'Ello again, DW. As promised, notes on my own attempts at game-ifying lifts:
My numbers are for a non-GURPS, in-progress home-brew. The rules themselves employ "log" stats, which will be meaningless out of context, so I've translated that to lift in kg (it's metric-based).
The base stats below are for a normal human. The source is limited data on "normal people" lifts, plus some reverse-engineering from record-setting lifts, plus a little self-measurement (based on a purely arbitrary guess at my own strength).
I put a lot of thought into the numbers, but now upon dusting them off a bit, they feel a bit low. Keep in mind that they're for a "base" adult, not notably athletic, and not necessarily male at that. They're also entirely prior to any sort of bonus from unusual effort or skill. So assuming for the moment that they may be realistic:
One-hand lifts
Two-hand lifts
Specialty lifts
Unlike the above smooth overhead lift, the below have the lifter raising the weight partway and then "slipping under" (pardon me if my terminology is far from professional). The numbers assume a successful skill check for proper execution (but no other special bonus for skill).
Notes
My ratio of Clean and Jerk to Snatch is 5/4, nicely close to your suggested 6/5.
I didn't tackle bench press, but I'll take your word for it: roughly 25% higher than Clean and Jerk. I can use that; thanks!
Now, what I don't recall is how I tied those to max human lift – i.e., what multiplier I used. I can probably dig it up, but the end results should be along the lines of yours; I'm sure we looked at much of the same record lift data.
And something I haven't done is explicitly tie max lift to lifter weight, as you have in this thread, other than via basic scaling: max human strength in my rules will generally require the scaled-up size of a large lifter, with appropriately scaled-up weight.
Whenever I make this skeleton of a rules-set public, it should provide a few interesting bones for the rules hacker crowd to pick over. Your notes on size and ST are helpful to me and to GURPS hackers as well.