Related Experiment Video
Updated: Aug 31, 2025
Muscle Imbalances: Testing and Training Functional Eccentric Hamstring Strength in Athletic Populations
Published on: May 1, 2018
Effect of Sex and Maturation on Knee Extensor and Flexor Strength in Adolescent Athletes
Kerry Peek1, Kevin R Ford2, Gregory D Myer3,4,5,6
1Discipline of Physiotherapy, Faculty of Medicine and Health, The University of Sydney, Camperdown, New South Wales, Australia.
Background:
Despite knee extensor and flexor strength reportedly being associated with injury risk, including rupture of the anterior cruciate ligament in girls, there is limited evidence for the longitudinal changes in lower extremity strength.
Purpose:
To investigate the sex-specific relationship with longitudinal changes of knee extensor and flexor strength associated with maturation.
Study Design:
Cohort study; Level of evidence, 2.
Methods:
Adolescent boys and girls (N = 257; 208 adolsecent girls) participating in high school basketball, volleyball, and soccer were assessed longitudinally in at least 2 different pubertal stages. Pubertal status (prepubertal, pubertal, and postpubertal) was determined with the modified Pubertal Maturation Observation Scale questionnaire. After a warm-up of 5 submaximal repetitions, participants were tested for concentric peak isokinetic strength for knee extension and flexion at 300 deg/s over 10 repetitions and normalized to body weight. Linear mixed models were used to test for the effect of pubertal stage, sex, and their interaction.
Results:
Significant interactions were identified that indicated different maturational trajectories for knee muscle strength for adolescent boys and girls, particularly between prepubertal and pubertal stages, in which boys demonstrated greater mass normalized knee extensor increases than girls (right, +12% vs +5%; left, +13% vs +7%; P < .001). For knee flexors, boys demonstrated increased strength, while girls demonstrated decreased relative knee flexor strength (right, +4% vs -1%, P = .03; left, +3 vs -3%, P = .009).
Conclusion:
The findings of this study support a differential effect of sex and maturation on important knee strength outcomes that may have implications for knee injury reduction, particularly in adolescent girls as they mature.
Related Concept Videos
01:16Bones of the Lower Limb: Femur and Patella
01:27Signs of Puberty
01:09Changes in the Appendicular Skeleton with Age
Initially, the limb buds consist of a core of mesenchyme covered by a layer of ectoderm. The ectoderm at the end of the limb bud thickens to form a narrow crest called the apical ectodermal ridge. This ridge stimulates the underlying...
01:23Muscles that Move the Leg
Anterior Compartment
The quadriceps femoris, the most visible muscle of the anterior compartment, is integral for leg extension and thigh flexion. It is formed by merging four distinct muscles — the vastus lateralis, vastus medialis, vastus intermedius, and rectus femoris. The quadriceps tendon, a shared tendon of the four quadriceps muscles, is affixed...
01:27Exercise and Muscle Performance
Endurance exercises
Endurance exercises involve running, swimming, or cycling, which require repetitive movements with low force output. When a person engages in endurance exercise, a few noticeable changes occur in their skeletal muscles. For instance, the number of capillaries...