The hamstrings to quadriceps functional ratio expressed over the full angle-angular velocity range using a limited...

Area of Science:

• Biomechanics
• Sports Medicine
• Musculoskeletal Research

Background:

• The hamstring to quadriceps (H:Q) strength ratio is a common metric for assessing hamstring strain injury risk.
• Current H:Q ratio calculations are limited, often providing only 1D or 2D representations and neglecting crucial muscle mechanics.

Purpose of the Study:

• To develop and validate a novel 3D functional H:Q ratio model.
• To improve the accuracy and comprehensiveness of H:Q ratio assessment for injury risk identification.

Main Methods:

• Collected isokinetic torque data for knee flexors and extensors (0-400° s⁻¹) in 25 physically active males.
• Derived a model equation to create a 3D H:Q functional ratio profile.
• Tested model robustness with varying data points (8, 11, 14, 17) and joint angle perturbations (5°).

Main Results:

• The 3D H:Q functional ratio model demonstrated robustness and consistency across tested conditions, performing well with as few as 11 data points.
• The model accurately described the H:Q functional ratio even at unassessed angles and velocities.
• Model performance was slightly reduced with only 8 data points (R² = 0.84-0.96; RMSE = 0.14-0.25; NRMSE = 0.12-0.27).

Conclusions:

• The developed 3D H:Q functional ratio model provides a fast, accurate, and comprehensive assessment of knee joint muscle strength balance.
• This model has the potential to serve as an easily implementable screening tool for identifying individuals at risk of hamstring strain injuries.