title: Hamstrings-to-quadriceps strength and size ratios of male professional soccer players with muscle imbalance.
abstract: The aim of this study was to determine the correlation between the concentric hamstrings/quadriceps muscle strength (Hcon :Qcon ) and cross-sectional area ratios (Hcsa :Qcsa ) in professional soccer players with Hcon :Qcon imbalance. Nine male professional soccer players (25·3 ± 4·1 years) performed five maximal concentric contractions of the knee extensors (KE) and flexors (KF) at 60 s(-1) to assess Hcon :Qcon . The test was performed using the dominant (preferred kicking), and non-dominant limb with a 5-min recovery period was allowed between them. Only players with Hcon :Qcon < 0·60 (range: 0·45-0·59) in both limbs were included in this study. The muscle cross-sectional area (CSA) of KE and KF was determined by magnetic resonance imaging. The correlations between Hcon :Qcon and Hcsa :Qcsa in the dominant leg (r = -0·33), non-dominant leg (r = 0·19) and in the both legs combined (r = 0·28) were not statistically significant (P>0·05). Thus, the Hcon :Qcon seems not to be determined by Hcsa :Qcsa in professional soccer players with Hcon :Qcon imbalance.
authors.affiliation: Human Performance Laboratory, UNESP, Rio Claro, SP, Brazil.
authors.forename: Benedito Sérgio
authors.identifier: http://orcid.org/0000-0003-0775-1889
authors.initials: BS
authors.lastname: Denadai
authors.affiliation: Human Performance Laboratory, UNESP, Rio Claro, SP, Brazil.
authors.forename: Felipe Bruno Dias
authors.initials: FB
authors.lastname: de Oliveira
authors.affiliation: Human Performance Laboratory, UNESP, Rio Claro, SP, Brazil.
authors.forename: Sérgio Ricardo de Abreu
authors.initials: SR
authors.lastname: Camarda
authors.affiliation: Human Performance Laboratory, UNESP, Rio Claro, SP, Brazil.
authors.forename: Leandro
authors.initials: L
authors.lastname: Ribeiro
authors.affiliation: Human Performance Laboratory, UNESP, Rio Claro, SP, Brazil.
authors.forename: Camila Coelho
authors.initials: CC
authors.lastname: Greco
mesh_terms: D000328:Adult; D053587:Arthrometry, Articular; D056352:Athletes; D001696:Biomechanical Phenomena; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009119:Muscle Contraction; D053580:Muscle Strength; D053581:Muscle Strength Dynamometer; D052097:Quadriceps Muscle / Q000033:anatomy & histology* / Q000502:physiology*; D012916:Soccer; D019415:Torque; D055815:Young Adult
keywords: asymmetry; cross-sectional area; injury; isokinetic; magnetic resonance imaging; torque