It’s a common belief that boys naturally become stronger than girls, especially during and after puberty. But is this really true? Or are there other factors at play that contribute to strength differences between males and females?
Summary
Research shows there are some natural biological factors that make boys generally stronger than girls, especially in upper body strength. Key factors include:
- Higher testosterone levels in males during and after puberty
- More muscle mass and less body fat in males
- Broader shoulders and narrower hips in males
- Larger bones and muscle fibers in males
However, the strength gap between males and females is greatly influenced by other variables besides biology. These include nutrition, training, genetics, and motivational factors. With proper training and dedication, many females can become as strong as or stronger than untrained males.
Do Males Have an Innate Strength Advantage?
When it comes to brute muscular strength and power, males do appear to have some innate biological advantages. Here’s a quick overview of the key factors:
Testosterone
Testosterone is the primary male sex hormone and plays a major role in building muscle mass and strength. Males see a large surge in testosterone production during puberty.
- Average testosterone levels in adult males are 7-8 times higher than adult females.
- Higher testosterone translates to greater potential for muscle growth and strength gains.
Muscle Mass
On average, adult males have more skeletal muscle mass and less body fat compared to females. Muscle mass is a key component of strength.
- Males have approximately 40-50% more muscle mass in their upper bodies and 30-40% more in their lower bodies.
- Males generally have broader shoulders and narrower hips, allowing more muscle mass to be built in the upper body.
Bone Size
Males typically have larger and denser bones with wider frames and joint surfaces. This provides more area for muscle attachment.
- Male bones are generally 10-15% larger than female bones.
- Larger bones allow greater forces and loads to be exerted by attached muscles.
Muscle Fiber Composition
Males tend to have a higher proportion of fast-twitch muscle fibers in their muscles compared to females. Fast-twitch fibers contract faster and with more force.
- Fast-twitch fibers are 2-3x more abundant in males than females in muscles like the biceps.
- Allows for more explosive strength, speed, and power.
Overall, the average male naturally has higher muscle mass, bigger bones, more strength-oriented muscle fibers, and sky-high testosterone levels. This creates a significant strength advantage over females on average.
Strength Differences Between Males and Females
Numerous studies have quantified the differences in muscular strength between males and females. Here’s a look at some of the research:
Upper Body Strength
The biggest gender differences in strength tend to be seen in the upper body, which is more sensitive to testosterone:
- Untrained males have ~60-130% greater upper body strength than untrained females.
- The grip strength of adult males was 70% greater than females in one study.
- Elite male athletes can have 2-3x greater upper body strength than elite females.
Lower Body Strength
The strength gap tends to be smaller in the lower body:
- Untrained males have ~40-60% greater lower body strength than untrained females.
- Male leg strength was 61% greater than females in one trial.
- Elite males have ~30-40% greater lower body strength than elite females.
While smaller than upper body differences, the lower body strength gap is still quite substantial.
Strength Relative to Body Size
When taking into account muscle mass and overall body size, the gender gaps in strength are reduced but still present:
- Males are ~40-50% stronger pound-for-pound than females in the upper body.
- Males have ~20-30% greater lower body strength relative to lean mass.
This indicates much of the strength difference is explained by greater muscle mass. But a gender gap remains even when accounting for size.
Changes During Puberty
The divergence in strength between males and females really accelerates during and after puberty due to major hormonal changes:
- By age 12-14, boys begin outperforming girls in tests of speed, power, and strength.
- During puberty, males gain approximately 30 pounds more muscle mass than females.
- Post-puberty, adult males are 50-100% stronger than adult females in the upper and lower body.
Here is a table illustrating how the gender strength gap widens with age as males go through puberty:
| Age Group | Typical Gender Strength Gap |
|---|---|
| Pre-Puberty (Under 11) | 10-30% |
| Early Puberty (11-14) | 30-60% |
| Post-Puberty (15-18+) | 50-100%+ |
The large influx of testosterone produces rapid muscle growth in males that extends the natural strength advantage over females.
Other Biological Factors
While testosterone and muscle mass are the biggest biological drivers, there are some other physical factors that may contribute as well:
Genetics and Body Type
Males tend to inherit physical traits like higher fast-twitch muscle fiber content, larger bones, and greater height/weight that aid strength potential.
Energy Metabolism
Males tend to have greater anaerobic energy capacity. This allows faster ATP regeneration for short, intense muscle contractions.
Motor Unit Recruitment
Males may be able to activate more muscle motor units simultaneously, enabling greater force production.
Psychology and Motivation
Societal expectations and motivations regarding strength and physique are different for males and females on average.
However, experts disagree on the relative influence of each of these secondary factors compared to testosterone and muscle mass.
The Role of Training
While biological differences give males an overall strength advantage, proper training can significantly reduce this gap between genders. Some key points:
- Untrained females have approximately half the strength of untrained males.
- But trained females can reach 60-90% of male strength levels with consistent training.
- Many trained females can outlift untrained or novice males.
- A small percentage of elite females can exceed male strength averages.
Additionally, females may have advantages over men in some areas like:
- Ability to fatique less during endurance training
- Greater lower body strength relative to lean mass
- Enhanced motor control and coordination
With proper programming and dedication, women can achieve remarkable levels of strength through training.
The Influence of Nutrition
Proper nutrition is key to building muscle and strength for both genders. Key nutrition factors include:
- Sufficient calories to build muscle mass
- Adequate protein intake to support muscle protein synthesis
- Carbs to fuel workouts and recovery
- Healthy fats for hormones and joint health
However, societal pressures for thinness may cause some females to undereat. This can make building strength difficult:
- Low energy availability prevents optimal strength and muscle gains.
- Low protein intake reduces muscle protein synthesis.
Ensuring proper calorie intake and nutrient balance is key for females to gain strength and offset biological differences.
Conclusion
In summary, biological factors do make males naturally stronger than females on average, especially in the upper body. But many of these gender differences can be reduced or eliminated with proper training, nutrition, and motivation. While males may have a head start, females can achieve impressive levels of strength through dedicated training and optimal nutrition.