Muscle Cross-Sectional Area

CSA Arm

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Do tall athletes always have an advantage over shorter athletes? Biomechanics tells us that it is the cross-sectional area of a muscle that determines its potential for force production. This means that the amount of force a muscle can exert is directly proportional not to the volume (height * length * width) or length (distance from one end to the other) of a muscle, but to its width, the distance between its two sides (perpendicular to its longitudinal dimension at its largest point).  It doesn’t matter, then, how tall an athlete is; what counts is how thick the muscles are. If anything, taller athletes are at a disadvantage. If a tall athlete (Tower) and a short athlete (Broad or, better yet, Broadette) have the same amount of lean body mass, because Tower is taller, his muscle mass is more spread out, which means that, generally speaking, his muscles are “thinner” than Broad’s. In addition, because he is taller, Tower’s muscles have more weight to carry (e.g. the extra skeleton) than Broad, who can perform movements that feel “lighter” quicker. Strength is thus better measured as a proportion of height rather than by lean body mass alone.

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