Uploaded January 2025 | Updated September 2026, 2 weeks ago
Skinny guys sometimes outlift much bigger guys because strength depends on many other things besides muscle size.
Two of the factors that affect strength the most are bone segment lengths and tendon insertions.
Due to the way levers work, the amount of muscle force needed to lift a weight is not identical between individuals: it depends on the length of the bone the muscle pulls on and the distance between the point of tendon attachment and the joint.
For example, if one individual has 2 cm shorter forearms compared to another guy, the muscle force required to curl a dumbbell decreases by about 6%. But the tendon attachment location makes a much bigger difference. If the biceps tendon attaches just 0.5 cm further away from the joint, the muscle force needed to curl a dumbbell decreases by about 10%.
People who are unusually strong for their size likely have tendons which attach further away from their joints, and bone structures which create favorable leverages. This can allow them to lift 10-30% more weight than other guys despite generating the same muscle force.
Skinny guys sometimes outlift much bigger guys because strength depends on many other things besides muscle size.
Two of the factors that affect strength the most are bone segment lengths and tendon insertions.
Due to the way levers work, the amount of muscle force needed to lift a weight is not identical between individuals: it depends on the length of the bone the muscle pulls on and the distance between the point of tendon attachment and the joint.
For example, if one individual has 2 cm shorter forearms compared to another guy, the muscle force required to curl a dumbbell decreases by about 6%. But the tendon attachment location makes a much bigger difference. If the biceps tendon attaches just 0.5 cm further away from the joint, the muscle force needed to curl a dumbbell decreases by about 10%.
People who are unusually strong for their size likely have tendons which attach further away from their joints, and bone structures which create favorable leverages. This can allow them to lift 10-30% more weight than other guys despite generating the same muscle force.
