title: Angle-specific hamstring-to-quadriceps ratio: a comparison of football players and recreationally active males.
abstract: It is currently unclear how football participation affects knee-joint muscle balance, which is widely considered a risk factor for hamstrings injury. This study compared the angle-specific functional hamstring-to-quadriceps (H:Q) ratio (hamstrings eccentric torque as a ratio of quadriceps concentric torque at the same knee-joint angle) of football players with recreationally active controls. Ten male footballers and 14 controls performed maximal voluntary isometric and isovelocity concentric and eccentric contractions (60, 240 and 400° s(-1)) of the knee extensors and flexors. Gaussian fitting to the raw torque values was used to interpolate torque values for knee-joint angles of 100-160° (60° s(-1)), 105-160° (240° s(-1)) and 115-145° (400° s(-1)). The angle-specific functional H:Q ratio was calculated from the knee flexors eccentric and knee extensors concentric torque at the same velocity and angle. No differences were found for the angle-specific functional H:Q ratio between groups, at any velocity. Quadriceps and hamstrings strength relative to body mass of footballers and controls was similar for all velocities, except concentric knee flexor strength at 400° s(-1) (footballers +40%; P < 0.01). In previously uninjured football players, there was no intrinsic muscle imbalance and therefore the high rate of hamstring injuries seen in this sport may be due to other risk factors and/or simply regular exposure to a high-risk activity.
authors: a School of Sport, Exercise and Health Sciences , Loughborough University , Loughborough , UK.
authors: Pavlos Eleftherios
authors: PE
authors: Evangelidis
authors: Matthew Thomas Gerard
authors: MT
authors: Pain
authors: Jonathan
authors: J
authors: Folland
mesh_terms: D000328:Adult; D015992:Body Mass Index; D006801:Humans; D007719:Knee Joint / Q000502:physiology*; D008297:Male; D009119:Muscle Contraction / Q000502:physiology; D053580:Muscle Strength / Q000502:physiology; D018482:Muscle, Skeletal / Q000502:physiology*; D052097:Quadriceps Muscle / Q000502:physiology*; D016059:Range of Motion, Articular; D011998:Recreation / Q000502:physiology; D012916:Soccer / Q000502:physiology*; D019415:Torque; D055815:Young Adult
keywords: functional ratio; isokinetic strength ratio; knee-joint imbalances; muscle balance; reciprocal strength; soccer