The question of whether a girl can be stronger than a guy is complex, requiring an understanding of human physiology and how strength is measured. While population averages show a consistent difference between the sexes, these generalizations do not account for individual variation, training dedication, or the specific type of strength being tested. The biological factors that create the average strength disparity can be largely overcome by dedicated training or negated entirely when evaluating strength relative to body composition or over long durations. A look at hormones, muscle structure, and definitions of strength clarifies the nuances of this comparison.
Physiological Foundations of Strength Differences
The average difference in strength between males and females is rooted primarily in hormonal and body composition differences that emerge during puberty. The hormone testosterone, which is present at levels approximately 15 times higher in adult males than in females, drives greater muscle development. Testosterone stimulates protein synthesis and leads to a significantly larger muscle mass and larger muscle fiber cross-sectional area (CSA) in men compared to women.
Women have higher levels of estrogen, which promotes muscle repair but does not drive the same level of absolute muscle hypertrophy as testosterone. This difference in muscle mass means that women’s total body absolute strength is typically about two-thirds that of men. The disparity is more pronounced in the upper body (about 56% of men’s strength) compared to the lower body (averaging closer to 72%).
The wider disparity in upper body strength is explained by the distribution of lean body mass, as males carry a much higher proportion of muscle mass in their upper body. Despite these anatomical differences, the actual quality of the muscle tissue—the force generated per unit of muscle size—is virtually identical between the sexes. This means the strength difference is quantitative, based on volume, rather than qualitative, based on the muscle’s inherent ability to contract.
Defining Strength: Absolute, Relative, and Endurance
Understanding the comparison requires defining strength in three distinct ways: absolute, relative, and muscular endurance. Absolute strength refers to the maximum force an individual can exert, such as the heaviest weight they can lift, irrespective of body size. In this measure, the average man is stronger than the average woman due to greater overall muscle mass and fiber area.
Relative strength, however, is a measure of strength proportional to body weight or lean body mass. When strength is calculated relative to an individual’s amount of fat-free mass, the difference between the sexes largely disappears, especially in the lower body. For instance, a woman who deadlifts twice her body weight is demonstrating superior relative strength compared to a man who lifts one and a half times his body weight.
The third measure, muscular endurance, focuses on the ability to sustain sub-maximal force over an extended period or through many repetitions. Women often demonstrate an advantage in this category, showing greater resistance to fatigue during sustained, low-intensity contractions. This endurance advantage is partly attributed to women having a higher proportion of Type I, or slow-twitch, muscle fibers, which are highly fatigue-resistant.
This superior fatigue resistance is demonstrated in ultra-endurance events, which demand sustained effort over many hours or days. Women have a metabolic profile, influenced by estrogen, that allows for more efficient fat oxidation and the conservation of glycogen. In ultra-marathon distances exceeding 195 miles, female runners have matched or surpassed the performance of their male counterparts, shrinking the performance gap seen in shorter events.
How Training and Individuality Impact Outcomes
Population averages only represent the midpoint of a wide spectrum of human capability and do not determine individual potential. A highly trained woman can easily exceed the strength of an untrained or recreationally active man. The strength difference between the sexes is most pronounced when comparing the average man to the average woman, but a dedicated strength athlete’s physical conditioning often overrules this biological baseline.
Women who engage in consistent, specialized resistance training see significant strength gains, and the relative increase in muscle size following training is comparable to that of men. This means a highly conditioned female powerlifter, for example, who trains for years can achieve feats of strength that remain unattainable for the vast majority of the male population. Many elite female lifters have successfully deadlifted more than three and a half times their body weight, a benchmark few untrained men ever approach.
The difference between general athleticism and specific strength conditioning is important. When comparing a highly specialized, genetically gifted, and well-trained girl to an average or untrained guy, the girl can be demonstrably stronger in absolute terms. The answer to the question ultimately depends on the training, effort, and individual genetic factors of the specific people being compared.