Sex Differences in Muscle Strength, Endurance, Activation, Size, Fiber Type, and Strength Training Participation Rates, Preferences, Motivations, Injuries, and Neuromuscular Adaptations
All of it.
Have you ever wondered exactly why men and women are so different in the weight room, or why their motivations and injury risks differ? This study examines the influence of biological sex on muscle characteristics and strength training outcomes, providing insights for athletes, trainers, and health enthusiasts seeking personalised and effective exercise programs.
Key Points
Aim
The review aims to comprehensively summarise existing literature on sex differences in:
Muscle strength, endurance, and activation
Muscle size, mass, and fiber type
Strength training participation rates, preferences, and motivations
Injury rates and neuromuscular adaptations to strength training
It seeks to clarify how these differences manifest across age, muscle groups, contraction types, and training responses.
Methods
This is a narrative review compiling results from numerous studies on sex differences in muscle-related variables. It includes data on:
Muscle strength across ages and muscle groups
Muscle endurance during different contraction types
Muscle fiber composition
Psychological and sociological factors influencing training participation
Injury incidence and recovery profiles
The review also presents sex differences as female values expressed as a percentage of male values for clarity.
Findings
Muscle Strength and Development
Age-related differences: Before puberty (~10 years), girls’ grip strength is about 95% of boys’, but this difference is not statistically significant. Around age 14–15, boys experience a marked increase in strength, with girls’ grip strength dropping to roughly 75% of boys’ at this age. Peak strength occurs between 25–30 years for both sexes, but men’s strength increases more dramatically from puberty to adulthood.
Muscle group differences: Sex differences are more pronounced in upper-body muscles than in lower-body muscles. Men tend to be stronger in concentric contractions compared to eccentric contractions relative to women.
Muscle mass and fiber type: Men have greater muscle mass and larger type II (fast-twitch) fiber areas, which largely explain their higher strength levels. Voluntary activation (neural drive) does not differ significantly between sexes.
Muscle Endurance
Women generally have greater muscle endurance (fatigability) during isometric contractions. However, data on endurance during eccentric-concentric contractions typical of strength training are less clear but suggest some sex differences that may influence training volume and load prescription.
Strength Training Participation, Preferences, and Motivations
Participation rates: Men participate in strength training more frequently than women.
Motivations: Men are motivated by challenge, competition, social recognition, and increasing muscle size and strength. Women are more motivated by improving attractiveness, muscle toning, and body mass management.
Preferences: Men prefer competitive, high-intensity, and upper-body-focused exercise. Women prefer supervised training, and lower-body focus, and often value social support and structured environments.
Adaptations to Strength Training
Both men and women increase muscle size and strength with training, but women typically experience greater relative strength improvements, depending on age and muscle group.
Men tend to have higher injury rates during strength training.
No significant sex differences exist in strength loss or muscle soreness following muscle-damaging exercise.
