Knee and hip loading patterns at different phases in the menstrual cycle

Chaudhari AM, Lindenfeld TN, Andriacchi TP, Hewett TE, Riccobene J, Myer GD, Noyes FR: Knee and hip loading patterns at different phases in the menstrual cycle: Implications for the gender difference in ACL injury rates. Am J Sports Medicine 35: 793-800, 2007.

“Reprinted with permission of the American Journal of Sports Medicine. Further reproduction is prohibited.”

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Background: Menstrual cycle phase has been correlated with risk of noncontact anterior cruciate ligament injury in women. The mechanism by which hormonal cycling may affect injury rate is unknown.

Hypotheses: Jumping and landing activities performed during different phases of the menstrual cycle lead to differences in foot strike knee flexion, as well as peak knee and hip loads, in women not taking an oral contraceptive but not in women taking an oral contraceptive. Women will experience greater normalized joint loads than men during these activities.

Study Design: Controlled laboratory study.

Methods: Twenty-five women (13 using oral contraceptives) and 12 men performed repeated trials of a horizontal jump, vertical jump, and drop from a 30-cm box on the left leg. Lower limb kinematics (foot strike knee flexion) and peak externally applied moments were calculated (hip adduction moment, hip internal rotation moment, knee flexion moment, knee abduction moment). Men were tested once. Women were tested twice for each phase of the menstrual cycle (follicular, luteal, ovulatory), as determined from serum analysis. An analysis of variance was used to examine differences between phases of the menstrual cycle and between groups ( = .05).

Results: No significant differences in moments or knee angle were observed between phases in either female group or between the 2 female groups or between either female group and the male controls.

Conclusions: Variations of the menstrual cycle and the use of an oral contraceptive do not affect knee or hip joint loading during jumping and landing tasks.

Clinical Relevance: Because knee and hip joint loading is unaffected by cyclic variations in hormone levels, the observed difference in injury rates is more likely attributable to persistent differences in strength, neuromuscular coordination, or ligament properties.

 

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Understanding and preventing non-contact ACL injuries

Understanding and preventing non-contact ACL

injuries: A review of the Hunt Valley II meeting, January 2005. Griffin LY, …Noyes FR, …et al. Am J Sports Med 34: 1512-1532, 2006.

“Reprinted with permission of the American Journal of Sports Medicine.

Further reproduction is prohibited.”

The incidence of noncontact anterior cruciate ligament injuries in young to middle-aged athletes remains high. Despite early diagnosis and appropriate operative and nonoperative treatment, post-traumatic degenerative arthritis may develop. In a meeting in Atlanta, Georgia (January 2005), sponsored by the American Orthopaedic Society for Sports Medicine (AOSSM), a group of physicians, physical therapists, athletic trainers, biomechanists, epidemiologists, and other scientists interested in this area of research met to review current knowledge on risk factors associated with noncontact anterior cruciate ligament injuries, anterior cruciate ligament injury biomechanics and existing anterior cruciate ligament prevention programs. This article reports on the presentations, discussions and recommendations of this group.

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Assessment of lower limb neuromuscular control in prepubescent athletes

From the Cincinnati Sportsmedicine Research and Education Foundation and Deaconess Hospital, Cincinnati, Ohio

“Reprinted with permission of the American Journal of Sports Medicine. Further reproduction is prohibited.

Barber-Westin SD, Galloway

MG, Corbett

G, Noyes FR, Walsh C: Assessment of lower limb neuromuscular control in prepubescent athletes. Am J Sports Medicine 33, 1853-1860, 2005.

ABSTRACT

Background: While neuromuscular indices have been studied extensively in adolescents and adults, limited data exist for prepubescent children.

Hypothesis: No differences exist between prepubescent boys and girls in lower limb strength, symmetry on single-legged hop testing, and limb alignment during drop-jump testing.

Design: Cross-sectional study (prevalence); Level of evidence, 1.

Methods: The authors tested 27 female and 25 male athletes who were 9 to 10 years and matched for both body mass index and years of organized sports participation. In a drop-jump screening test, the distance between the right and left hips, knees, and ankles was measured as an indicator of lower limb axial alignment in the coronal plane. The distance between the knees and ankles was normalized by the hip separation distance. Quadriceps and hamstrings strengths were measured isokinetically at 180 deg/sec. Lower limb symmetry was determined from 2 single-legged hop function tests.

Results: Boys demonstrated greater mean absolute and normalized ankle and knee separation distances on the drop-jump test. Even so, 76% of boys had a normalized knee separation distance of 60% or less of the hip separation distance, as did 93% of girls, indicating a distinctly valgus alignment. There were no differences between the sexes in quadriceps and hamstrings peak torques, hamstrings/quadriceps ratio, time to peak torque, total work, or lower limb symmetry values.

Conclusions: A high percentage of prepubescent athletes studied had a distinctly valgus lower limb alignment during the drop-jump test and a lack of lower limb symmetry during the hop tests. These same indices have been hypothesized to increase the risk for knee ligament injuries in older athletes. Neuromuscular training may be needed to address these issues in children.

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Isokinetic profile and differences in tibial rotation strength between males and female athletes 11 to 17 years of age

Noyes FR, Barber-Westin SD: Isokinetic profile and differences in tibial rotation strength between males and female athletes 11 to 17 years of age. Isok and Exer Sci 13: 251-259, 2005.

From the Cincinnati Sportsmedicine Research and Education Foundation

Our objective was to examine age and sex associated development of isokinetic tibial rotation strength in 94 athletes aged 11 to 17 years.

A calibrated Biodex system 3 was used to measure internal rotation (IR) and external rotation (ER) peak torque and time to peak torque (TPT) at 120°/s and 180°/s, and knee extension and flexion peak torque at 180°/s. All data were normalized for body weight and ANOVA identified significant (P < .05) effects of lower limb dominance, age and gender.

Males aged 14 to

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17 years had significantly greater mean IR, ER, flexion, and extension peak torques than males aged 11 to 13 years. No such age-related effect existed in females. There was no difference between genders aged 11 to 13 years in isokinetic strength. Males aged 14 to 17 years had on average 17% greater IR strength, 28% faster time to reach IR peak torque, 17% greater extension strength, and 20% greater knee flexion strength than age-matched females.

To conclude, no sex differences were found in peak torque or TPT in knee IR, ER, extension or flexion in athletes 11 to 13 years. Age related changes were found in these factors in males, but not in females.

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