[quote]larryb wrote:
If exactly proportional, then they would be stronger. Imagine a static hold in bench press, and an 8x proportional weight increase (double in height). Muscle cross-section is 4x larger (maximum force output is approximately proportional to cross-section). Limb length is double, but tendon attachment is also twice as far from the pivots, so the leverage is unchanged. So at least for the simple case of a static hold, a person 8 times heavier would be 4 times stronger, and a person twice the size would be about 1.6 times stronger.
Of course, tall people are generally not built like short people. Even if a bigger person were shaped exactly like a smaller person, the bigger person would require a larger proportion of bone mass for equivalent support - a fifty foot man exactly proportional to a normal six foot man would collapse under his own weight.[/quote]
Ahh, I see. Good points.
Kind of like the reason giant ants could never exist (for the same reason you listed about the 50ft man).
I just don’t like it when a tall, out of shape guy tells me that the reason my bench is good is because my arms are short (said as if to imply that’s the only reason). I know that no one here is implying that, but a guy I used to work with a while back, did.
I also asked about this on another forum a long time ago, and someone gave me the following study with references (I never checked the reference, butthe woman posting it is VERY reliable, and is a moderator for the formum I was on):
"Relationships of structural dimensions to bench press strength in college males.
Mayhew JL, Ball TE, Ward TE, Hart CL, Arnold MD.
Human Performance Laboratory, Northeast Missouri State University, Kirksville.
The purpose of this study was to determine the relationships between structural dimensions and bench press performance in college males.
Members of required fitness classes (n = 170) were measured after 14 weeks of strength and aerobic endurance training. Anthropometric dimensions included upper arm and chest circumferences, upper and lower arm lengths, shoulder and hip widths, %fat, and height.
Arm muscle cross-sectional area (CSA) was calculated from upper arm circumference corrected for triceps skinfold. Drop distance was measured from the bar to the pectoral muscles.
Multiple regression analysis selected upper arm CSA, %fat, and chest circumference as the best items to predict bench press strength (R = 0.83; SEE = 11.6 kg).
Cross-validation of the prediction equation on a similar sample (n = 89) produced an r = 0.74 between predicted and actual bench press (t = 0.53, p greater than 0.50).
In a second cross validation sample (n = 57) who had trained more extensively with weights, the correlation between predicted and actual bench press was r = 0.57 (p less than 0.05).
The prediction equations significantly (t = 6.59, p less than 0.01) underestimated bench press performance in the more extensively weight trained subjects.
The results of this study suggest that bench press performance is related to structural dimensions in males and that extensive strength training may alter the relationship between size and strength.
PMID: 1753717 [PubMed - indexed for MEDLINE]"
