Library
Lists
Topics
LibraryListsTopics
© 2026 Aurelian LLC|About·Privacy·Terms·Disclaimer·Support
|

Plyometric Training in Female Athletes. Decreased Impact Forces and Increased Hamstring Torques.

·Am J Sports Med·1996·1,014 citations·Sports Medicine
DOI·PubMed
SummaryAbstract on PubMed →

This prospective study tested whether a 6-week plyometric jump-training program changes landing mechanics and lower-limb strength in female high school volleyball players. Pre- and post-training landing forces, knee moments, and isokinetic strength were compared, with age- and height-matched male athletes as a reference. It asks whether trainable neuromuscular deficits underlie the higher knee injury rate in female athletes.

Study Snapshot

Design
Prospective intervention cohort
Blinding: Open-label
Setting: High school and gait laboratory, Cincinnati
Funding: None
Objective
Whether a 6-week plyometric jump-training program decreases landing forces and corrects strength imbalances in female athletes.
Outcome(s)
Peak landing force and knee moments before vs after training
Subjects
20 athletes
  • 11Female trained
  • 9Male controls
Inclusion
  • Female high school volleyball players
  • Age- and height-matched male controls
Follow-up
6-week training program with post-training testing
Statistics
Paired t-testANOVAMultiple regression

Key Findings

  • Peak landing forces from a volleyball block jump dropped 22% after training (2538 N to 2082 N, P = 0.006), and 10 of 11 athletes improved. Lower landing force translates directly to lower force at the knee.
  • Knee adduction and abduction (varus-valgus) moments fell roughly 50% and were the sole significant predictors of peak landing force on regression (P = 0.006). Sagittal flexion moments, jump height, and knee flexion angle were not predictive, pointing surgeons toward coronal-plane control as the target.
  • Before training, female athletes carried valgus and varus moments of 42 and 36 N-m, above the 35 N-m threshold that elicits pain and the 29 N-m threshold that loads collateral ligaments steeply. After training these dropped to about 20 and 22 N-m.
  • The hamstring-to-quadriceps peak torque ratio rose 26% nondominant and 13% dominant, lifting female athletes from 51% up to the male level of 65%. A ratio under 60% is hypothesized to predispose to serious knee injury.
  • Hamstring power increased 44% on the dominant leg and 21% on the nondominant. Stronger hamstrings compress the joint and restrain anterior tibial translation, offloading the ACL.
  • Male athletes showed external knee extension (hamstring-dominant) moments threefold higher than females, suggesting men recruit hamstrings to absorb landing while untrained women do not.
  • Vertical jump height increased about 10% (1.5 inches, P = 0.016) over just 6 weeks, showing the program improves performance while it corrects injury-risk mechanics.
Board PearlPlyometric training cut peak landing forces 22% and corrected the hamstring-to-quadriceps imbalance — the basis for ACL injury prevention programs in female athletes.

Clinical Relevance

Female athletes in jumping and cutting sports sustain serious knee injury at 4 to 6 times the rate of males, and this paper identifies trainable mechanics behind that gap.

The key teaching point: coronal-plane control matters more than sagittal. Knee adduction and abduction moments, not how deeply the knee flexes on landing, predicted peak force. When you counsel a young female athlete, the target is dynamic valgus control and hamstring strength, not simply telling her to bend her knees.

The hamstring-to-quadriceps ratio is a usable number. Untrained females sat at 51% versus 65% in males, and a ratio below 60% is hypothesized to raise injury risk. Six weeks of plyometrics corrected the imbalance. As the foundational neuromuscular training RCT preceding Hewett 1999, this work established the protocol that underpins modern ACL prevention programs.

Related Articles

Core

Plyometric Training in Female Athletes. Decreased Impact Forces and Increased Hamstring Torques.

Hewett, Noyes, et al.·Am J Sports Med·1996·1,014 citations·Sports Medicine
Landmark

Radiological Assessment of Osteo-Arthrosis.|

Kellgren, Lawrence·Ann Rheum Dis·1957·12,248 citations·General
Landmark

Mesenchymal Stem Cells.

Caplan·J Orthop Res·1991·6,470 citations·Basic Science
Landmark

Traumatic Arthritis of the Hip after Dislocation and Acetabular Fractures: Treatment by Mold Arthroplasty. an End-Result Study Using a New Method of Result Evaluation.

Harris·J Bone Joint Surg Am·1969·5,899 citations·Hip & Knee
Landmark

Bone: Formation by Autoinduction.

Urist·Science·1965·5,546 citations·Basic Science
Landmark

Treatment of Deep Cartilage Defects in the Knee with Autologous Chondrocyte Transplantation.|

Brittberg, Peterson, et al.·N Engl J Med·1994·5,478 citations·Sports Medicine
Landmark

Interrater Reliability of a Modified Ashworth Scale of Muscle Spasticity

Bohannon·Phys Ther·1987·5,350 citations·General
Landmark

Osteoclast Differentiation Factor Is a Ligand for Osteoprotegerin/osteoclastogenesis-Inhibitory Factor and Is Identical to Trance/rankl.|

Yasuda, Suda, et al.·Proc Natl Acad Sci U S A·1998·4,239 citations·Basic Science
Landmark

Comparison of Upper Gastrointestinal Toxicity of Rofecoxib and Naproxen in Patients with Rheumatoid Arthritis. Vigor Study Group.|

Bombardier, VIGOR Study Group, et al.·N Engl J Med·2000·4,036 citations·General
Landmark

Magnetic Resonance Classification of Lumbar Intervertebral Disc Degeneration.

Pfirrmann, Boos, et al.·Spine·2001·3,960 citations·Spine
Landmark

Novel Regulators of Bone Formation: Molecular Clones and Activities.

Wozney, Wang, et al.·Science·1988·3,906 citations·Basic Science
Landmark

The Diagnosis of Osteoporosis.

Kanis, Khaltaev, et al.·J Bone Miner Res·1994·3,840 citations·General
Landmark

"modes of Failure" of Cemented Stem-Type Femoral Components: a Radiographic Analysis of Loosening.

Gruen, Amstutz, et al.·Clin Orthop Relat Res·1979·3,647 citations·Hip & Knee
Landmark

Biomechanical Measures of Neuromuscular Control and Valgus Loading of the Knee Predict Anterior Cruciate Ligament Injury Risk in Female Athletes: a Prospective Study.

Hewett, Succop, et al.·Am J Sports Med·2005·3,495 citations·Sports Medicine
Landmark

Femoroacetabular Impingement: a Cause for Osteoarthritis of the Hip.

Ganz, Siebenrock, et al.·Clin Orthop Relat Res·2003·3,410 citations·Hip & Knee
Landmark

Noninvasive Treatments for Acute, Subacute, and Chronic Low Back Pain: a Clinical Practice Guideline from the American College of Physicians

Qaseem·Ann Intern Med·2017·3,311 citations·Spine
Landmark

Prevention of Infection in the Treatment of One Thousand and Twenty-Five Open Fractures of Long Bones: Retrospective and Prospective Analyses.

Gustilo, Anderson·J Bone Joint Surg Am·1976·3,211 citations·Trauma
Landmark

The Variation in Isometric Tension with Sarcomere Length in Vertebrate Muscle Fibres.

Gordon, Julian, et al.·J Physiol·1966·3,135 citations·Basic Science
Landmark

Osteoarthritis: a Disease of the Joint as an Organ.|

Loeser, Goldring, et al.·Arthritis Rheum·2012·2,961 citations·Basic Science
Landmark

Radiological Demarcation of Cemented Sockets in Total Hip Replacement.

DeLee, Charnley·Clin Orthop Relat Res·1976·2,913 citations·Hip & Knee
Landmark

Ectopic Ossification Following Total Hip Replacement. Incidence and a Method of Classification.

Brooker, Riley, et al.·J Bone Joint Surg Am·1973·2,880 citations·Hip & Knee
Landmark

The Operation of the Century: Total Hip Replacement.

Learmonth, Rorabeck, et al.·Lancet·2007·2,788 citations·Hip & Knee
Landmark

Fatty Muscle Degeneration in Cuff Ruptures. Pre- and Postoperative Evaluation by CT Scan.

Goutallier, Voisin, et al.·Clin Orthop Relat Res·1994·2,669 citations·Shoulder & Elbow
Landmark

Osseointegrated Titanium Implants. Requirements for Ensuring a Long-Lasting, Direct Bone-To-Implant Anchorage in Man.

Albrektsson, Lindström, et al.·Acta Orthop Scand·1981·2,662 citations·Basic Science
Landmark

The Etiology of Chondromalacia Patellae.

Outerbridge·J Bone Joint Surg Br·1961·2,659 citations·Sports Medicine
Landmark

Fracture and Dislocation Classification Compendium-2018.

Meinberg, Kellam, et al.·J Orthop Trauma·2018·2,622 citations·Trauma
Landmark

The Three Column Spine and Its Significance in the Classification of Acute Thoracolumbar Spinal Injuries.

Denis·Spine·1983·2,566 citations·Spine
Landmark

Dislocations after Total Hip-Replacement Arthroplasties.

Lewinnek, Zimmerman, et al.·J Bone Joint Surg Am·1978·2,549 citations·Hip & Knee
Landmark

Prevention and Treatment of Low Back Pain: Evidence, Challenges, and Promising Directions

Foster·Lancet·2018·2,489 citations·Spine
Landmark

Patient Satisfaction after Total Knee Arthroplasty: Who Is Satisfied and Who Is Not?|

Bourne, Charron, et al.·Clin Orthop Relat Res·2010·2,475 citations·Hip & Knee
Landmark

Problems in the Management of Type III (severe) Open Fractures: a New Classification of Type III Open Fractures.

Gustilo, Williams, et al.·J Trauma·1984·2,361 citations·Trauma
Landmark

The Value of Postural Reduction in the Initial Management of Closed Injuries of the Spine with Paraplegia and Tetraplegia. I.

Frankel, Walsh, et al.·Paraplegia·1969·2,283 citations·Spine
Landmark

Vacuum-Assisted Closure: a New Method for Wound Control and Treatment: Animal Studies and Basic Foundation.

Morykwas, McGuirt, et al.·Ann Plast Surg·1997·2,218 citations·Basic Science
Landmark

A System for the Functional Evaluation of Reconstructive Procedures after Surgical Treatment of Tumors of the Musculoskeletal System.

Enneking, Pritchard, et al.·Clin Orthop Relat Res·1993·2,209 citations·Oncology
Landmark

A Controlled Trial of Arthroscopic Surgery for Osteoarthritis of the Knee|

Moseley, Wray, et al.·N Engl J Med·2002·2,154 citations·Hip & Knee
Landmark

The Stabilizing System of the Spine. Part I. Function, Dysfunction, Adaptation, and Enhancement.

Panjabi·J Spinal Disord·1992·2,145 citations·Spine
Landmark

The Outcome and Repair Integrity of Completely Arthroscopically Repaired Large and Massive Rotator Cuff Tears.

Galatz, Yamaguchi, et al.·J Bone Joint Surg Am·2004·2,135 citations·Shoulder & Elbow
Landmark

The Tension-Stress Effect on the Genesis and Growth of Tissues. Part I. the Influence of Stability of Fixation and Soft-Tissue Preservation.

Ilizarov·Clin Orthop Relat Res·1989·2,120 citations·Basic Science
Landmark

A System for the Surgical Staging of Musculoskeletal Sarcoma.

Enneking, Goodman, et al.·Clin Orthop Relat Res·1980·2,112 citations·Oncology
Landmark

A Comprehensive Classification of Thoracic and Lumbar Injuries

Magerl·Eur Spine J·1994·2,067 citations·Spine
Landmark

Effect of the Tyrosine Kinase Inhibitor Sti571 in a Patient with a Metastatic Gastrointestinal Stromal Tumor|

Joensuu·N Engl J Med·2001·2,056 citations·Oncology
Landmark

Zoledronic Acid and Clinical Fractures and Mortality after Hip Fracture.|

Lyles, HORIZON Recurrent Fracture Trial, et al.·N Engl J Med·2007·1,995 citations·Trauma
Landmark

Factors of Patellar Instability: an Anatomic Radiographic Study.

Dejour, Guier, et al.·Knee·1994·1,987 citations·Sports Medicine
Landmark

Displaced Proximal Humeral Fractures. I. Classification and Evaluation.

Neer·J Bone Joint Surg Am·1970·1,957 citations·Trauma
Landmark

Hip Morphology Influences the Pattern of Damage to the Acetabular Cartilage: Femoroacetabular Impingement as a Cause of Early Osteoarthritis of the Hip.|

Beck, Ganz, et al.·J Bone Joint Surg Br·2005·1,955 citations·Hip & Knee
Core

Porosity of 3D Biomaterial Scaffolds and Osteogenesis.

Karageorgiou, Kaplan·Biomaterials·2005·6,476 citations·Basic Science
Core

A Report: the Definition and Classification of Cerebral Palsy April 2006.

Rosenbaum, Jacobsson, et al.·Dev Med Child Neurol·2007·4,795 citations·Pediatrics
Core

Clinician's Guide to Prevention and Treatment of Osteoporosis.|

Cosman, National Osteoporosis Foundation, et al.·Osteoporos Int·2014·4,062 citations·General
Core

Prevention of Venous Thromboembolism

Geerts·Chest·2008·3,825 citations·Hip & Knee
Core

The Development of Assessment of Spondyloarthritis International Society Classification Criteria for Axial Spondyloarthritis (part II): Validation and Final Selection|

Rudwaleit·Ann Rheum Dis·2009·3,656 citations·Spine
Core

Radiation Exposure from CT Scans in Childhood and Subsequent Risk of Leukaemia and Brain Tumours: a Retrospective Cohort Study.|

Pearce, Berrington de González, et al.·Lancet·2012·3,643 citations·Pediatrics
Core

Epidemiology of Adult Fractures: a Review.

Court-Brown, Caesar·Injury·2006·3,607 citations·Trauma
Core

Centers for Disease Control and Prevention Guideline for the Prevention of Surgical Site Infection, 2017.|

Berríos-Torres, Healthcare Infection Control Practices Advisory Committee, et al.·JAMA Surg·2017·3,442 citations·General
Core

Osteoblastic Cells Regulate the Haematopoietic Stem Cell Niche.|

Calvi, Scadden, et al.·Nature·2003·3,391 citations·Basic Science
Core

A Joint Coordinate System for the Clinical Description of Three-Dimensional Motions: Application to the Knee.

Grood, Suntay·J Biomech Eng·1983·3,309 citations·Basic Science
Core

Consensus Statement on Concussion in Sport-The 5th International Conference on Concussion in Sport Held in Berlin, October 2016.|

McCrory, Vos, et al.·Br J Sports Med·2017·3,303 citations·Sports Medicine
Core

Oarsi Guidelines for the Non-Surgical Management of Knee Osteoarthritis.|

McAlindon, Underwood, et al.·Osteoarthritis Cartilage·2014·3,129 citations·Hip & Knee
Core

Estimating the Prevalence of Limb Loss in the United States: 2005 to 2050.

Ziegler-Graham, Brookmeyer, et al.·Arch Phys Med Rehabil·2008·2,780 citations·General
Core

Metastasis to Bone: Causes, Consequences and Therapeutic Opportunities.

Mundy·Nat Rev Cancer·2002·2,765 citations·Oncology
Core

Role of Proinflammatory Cytokines in the Pathophysiology of Osteoarthritis.

Kapoor, Fahmi, et al.·Nat Rev Rheumatol·2011·2,711 citations·Basic Science
Core

The Basic Science of Articular Cartilage: Structure, Composition, and Function.|

Sophia Fox, Rodeo, et al.·Sports Health·2009·2,681 citations·Basic Science
Core

Osteoporosis: Now and the Future.|

Rachner, Hofbauer, et al.·Lancet·2011·2,604 citations·General
Core

Clinical Features of Metastatic Bone Disease and Risk of Skeletal Morbidity.

Coleman·Clin Cancer Res·2006·2,461 citations·Oncology
Core

Transfusion of Plasma, Platelets, and Red Blood Cells in a 1:1:1 vs. a 1:1:2 Ratio and Mortality in Patients with Severe Trauma: the Proppr Randomized Clinical Trial

Holcomb, PROPPR Study Group, et al.·JAMA·2015·2,453 citations·Trauma
Core

Direct Decompressive Surgical Resection in the Treatment of Spinal Cord Compression Caused by Metastatic Cancer: a Randomised Trial.

Patchell, Young, et al.·Lancet·2005·2,356 citations·Spine
Core

Fracture and Dislocation Classification Compendium - 2007: Orthopaedic Trauma Association Classification, Database and Outcomes Committee.

Marsh, Audigé, et al.·J Orthop Trauma·2007·2,343 citations·Trauma
Core

Peek Biomaterials in Trauma, Orthopedic, and Spinal Implants.|

Kurtz, Devine·Biomaterials·2007·2,304 citations·Basic Science
Core

Effect of Calcium and Vitamin D Supplementation on Bone Density in Men and Women 65 Years of Age or Older|

Dawson-Hughes·N Engl J Med·1997·2,295 citations·General
Core

The Long-Term Consequence of Anterior Cruciate Ligament and Meniscus Injuries: Osteoarthritis.|

Lohmander, Roos, et al.·Am J Sports Med·2007·2,251 citations·Sports Medicine
Core

Diagnosis and Management of Prosthetic Joint Infection: Clinical Practice Guidelines by the Infectious Diseases Society of America.|

Osmon, Infectious Diseases Society of America, et al.·Clin Infect Dis·2013·2,220 citations·Hip & Knee
Core

The Amazing Osteocyte.|

Bonewald·J Bone Miner Res·2011·2,169 citations·Basic Science
Core

Osteosarcoma Incidence and Survival Rates from 1973 to 2004: Data from the Surveillance, Epidemiology, and End Results Program.|

Mirabello, Savage, et al.·Cancer·2009·2,165 citations·Oncology
Core

Projected Volume of Primary Total Joint Arthroplasty in the U.s., 2014 to 2030.

Sloan, Sheth, et al.·J Bone Joint Surg Am·2018·2,092 citations·Hip & Knee
Core

The 2018 Definition of Periprosthetic Hip and Knee Infection: an Evidence-Based and Validated Criteria.

Parvizi, Shohat, et al.·J Arthroplasty·2018·2,065 citations·Hip & Knee
Core

Bone Quality--The Material and Structural Basis of Bone Strength and Fragility.

Seeman, Delmas·N Engl J Med·2006·2,052 citations·Basic Science
Core

Prevalence of Muscular Dystrophies: a Systematic Literature Review.|

Theadom, Feigin, et al.·Neuroepidemiology·2014·2,050 citations·Pediatrics
Core

Mechanisms of Bone Metastasis.

Roodman·Discov Med·2004·2,028 citations·Oncology
Core

The Compressive Behavior of Bone as a Two-Phase Porous Structure.

Carter, Hayes·J Bone Joint Surg Am·1977·1,998 citations·Basic Science
Emerging

Diagnosis and Treatment of Hip and Knee Osteoarthritis|

Katz, Loeser, et al.·JAMA·2021·2,126 citations·Hip & Knee
Supplemental

Denosumab for Prevention of Fractures in Postmenopausal Women with Osteoporosis.|

Cummings, FREEDOM Trial, et al.·N Engl J Med·2009·3,382 citations·General
Supplemental

Opgl Is a Key Regulator of Osteoclastogenesis, Lymphocyte Development and Lymph-Node Organogenesis.

Kong, Penninger, et al.·Nature·1999·3,356 citations·Basic Science
Supplemental

Osteoarthritis: New Insights. Part 1: the Disease and Its Risk Factors.

Felson, Fries, et al.·Ann Intern Med·2000·2,525 citations·Hip & Knee
Supplemental

Morbidity at Bone Graft Donor Sites.

Younger, Chapman·J Orthop Trauma·1989·2,008 citations·General
Reference

Induction of Pluripotent Stem Cells from Adult Human Fibroblasts by Defined Factors.

Takahashi, Yamanaka, et al.·Cell·2007·20,127 citations·Basic Science
Reference

Guidelines for the Process of Cross-Cultural Adaptation of Self-Report Measures

Beaton·Spine·2000·14,242 citations·General
Reference

Assessment of Coma and Impaired Consciousness. a Practical Scale.

Teasdale, Jennett·Lancet·1974·13,082 citations·Trauma
Reference

Development and Reliability of a System to Classify Gross Motor Function in Children with Cerebral Palsy

Palisano, Galuppi, et al.·Dev Med Child Neurol·1997·8,546 citations·Pediatrics
Reference

Validation Study of Womac: a Health Status Instrument for Measuring Clinically Important Patient Relevant Outcomes to Antirheumatic Drug Therapy in Patients with Osteoarthritis of the Hip or Knee.

Bellamy, Stitt, et al.·The Journal of rheumatology·1988·7,828 citations·Hip & Knee
Reference

Projections of Primary and Revision Hip and Knee Arthroplasty in the United States from 2005 to 2030.

Kurtz, Halpern, et al.·J Bone Joint Surg Am·2007·7,476 citations·Hip & Knee
Reference

The Oswestry Disability Index.

Fairbank, Pynsent·Spine·2000·5,651 citations·Spine
Reference

A Surgical Safety Checklist to Reduce Morbidity and Mortality in a Global Population.|

Haynes, Safe Surgery Saves Lives Study Group, et al.·N Engl J Med·2009·5,579 citations·General
Reference

A Clinical Method of Functional Assessment of the Shoulder.

Constant, Murley·Clin Orthop Relat Res·1987·5,271 citations·Shoulder & Elbow
Reference

Rating Systems in the Evaluation of Knee Ligament Injuries.

Tegner, Lysholm·Clin Orthop Relat Res·1985·4,572 citations·Sports Medicine
Reference

Sf-36 Health Survey Update

Ware·Spine·2000·4,490 citations·General
Reference

Rationale of the Knee Society Clinical Rating System.

Insall, Scott, et al.·Clin Orthop Relat Res·1989·4,195 citations·Hip & Knee
Reference

Measurement of Health Status|Citation only

Jaeschke·Controlled Clinical Trials·1989·4,150 citations·Shoulder & Elbow
Reference

Knee Injury and Osteoarthritis Outcome Score (koos)--Development of a Self-Administered Outcome Measure.

Roos, Beynnon, et al.·J Orthop Sports Phys Ther·1998·3,837 citations·Sports Medicine
Reference

Evaluation of Knee Ligament Surgery Results with Special Emphasis on Use of a Scoring Scale.

Lysholm, Gillquist·Am J Sports Med·1982·2,762 citations·Sports Medicine
Reference

Development and Validation of the International Knee Documentation Committee Subjective Knee Form.

Irrgang, Shelborne, et al.·Am J Sports Med·2001·2,141 citations·Sports Medicine
Reference

Delirium in Older Persons.|Citation only|

Inouye·N Engl J Med·2006·2,082 citations·General
Reference

Calcium Phosphate Ceramics as Hard Tissue Prosthetics.

Jarcho·Clin Orthop Relat Res·1981·2,003 citations·Basic Science
|

Plyometric Training in Female Athletes. Decreased Impact Forces and Increased Hamstring Torques.

·Am J Sports Med·1996·1,014 citations·Sports Medicine
DOI·PubMed
SummaryAbstract on PubMed →

This prospective study tested whether a 6-week plyometric jump-training program changes landing mechanics and lower-limb strength in female high school volleyball players. Pre- and post-training landing forces, knee moments, and isokinetic strength were compared, with age- and height-matched male athletes as a reference. It asks whether trainable neuromuscular deficits underlie the higher knee injury rate in female athletes.

Study Snapshot

Design
Prospective intervention cohort
Blinding: Open-label
Setting: High school and gait laboratory, Cincinnati
Funding: None
Objective
Whether a 6-week plyometric jump-training program decreases landing forces and corrects strength imbalances in female athletes.
Outcome(s)
Peak landing force and knee moments before vs after training
Subjects
20 athletes
  • 11Female trained
  • 9Male controls
Inclusion
  • Female high school volleyball players
  • Age- and height-matched male controls
Follow-up
6-week training program with post-training testing
Statistics
Paired t-testANOVAMultiple regression

Key Findings

  • Peak landing forces from a volleyball block jump dropped 22% after training (2538 N to 2082 N, P = 0.006), and 10 of 11 athletes improved. Lower landing force translates directly to lower force at the knee.
  • Knee adduction and abduction (varus-valgus) moments fell roughly 50% and were the sole significant predictors of peak landing force on regression (P = 0.006). Sagittal flexion moments, jump height, and knee flexion angle were not predictive, pointing surgeons toward coronal-plane control as the target.
  • Before training, female athletes carried valgus and varus moments of 42 and 36 N-m, above the 35 N-m threshold that elicits pain and the 29 N-m threshold that loads collateral ligaments steeply. After training these dropped to about 20 and 22 N-m.
  • The hamstring-to-quadriceps peak torque ratio rose 26% nondominant and 13% dominant, lifting female athletes from 51% up to the male level of 65%. A ratio under 60% is hypothesized to predispose to serious knee injury.
  • Hamstring power increased 44% on the dominant leg and 21% on the nondominant. Stronger hamstrings compress the joint and restrain anterior tibial translation, offloading the ACL.
  • Male athletes showed external knee extension (hamstring-dominant) moments threefold higher than females, suggesting men recruit hamstrings to absorb landing while untrained women do not.
  • Vertical jump height increased about 10% (1.5 inches, P = 0.016) over just 6 weeks, showing the program improves performance while it corrects injury-risk mechanics.
Board PearlPlyometric training cut peak landing forces 22% and corrected the hamstring-to-quadriceps imbalance — the basis for ACL injury prevention programs in female athletes.

Clinical Relevance

Female athletes in jumping and cutting sports sustain serious knee injury at 4 to 6 times the rate of males, and this paper identifies trainable mechanics behind that gap.

The key teaching point: coronal-plane control matters more than sagittal. Knee adduction and abduction moments, not how deeply the knee flexes on landing, predicted peak force. When you counsel a young female athlete, the target is dynamic valgus control and hamstring strength, not simply telling her to bend her knees.

The hamstring-to-quadriceps ratio is a usable number. Untrained females sat at 51% versus 65% in males, and a ratio below 60% is hypothesized to raise injury risk. Six weeks of plyometrics corrected the imbalance. As the foundational neuromuscular training RCT preceding Hewett 1999, this work established the protocol that underpins modern ACL prevention programs.

Related Articles