Original articles  EXERCISE PHYSIOLOGY AND BIOMECHANICS 

The Journal of Sports Medicine and Physical Fitness 2004 June;44(2):119-25

Copyright © 2009 EDIZIONI MINERVA MEDICA

language: English

Concentric quadriceps and hamstrings isokinetic strength in volleyball and soccer players

Magalhães J. ¹, Oliveira J. ², Ascensão A. ¹, Soares J. ¹

¹ Department of Sports Biology Faculty of Sport Sciences and Physical Education University of Porto, Porto, Portugal 2 Department of Sports Training Faculty of Sport Sciences and Physical Education University of Porto, Porto, Portugal

Aim. Mus­cular ­strength is one of the ­most impor­tant com­po­nents of ­sport, ­both for ­high per­for­mance and for ­injury pre­ven­tion. One of the ­most ­used ­methods to ­assess ­strength ­muscle bal­ance ­between dom­i­nant (D)/non-dom­i­nant (ND) and antag­o­nist/ago­nist is iso­ki­netic ­testing. The ­main pur­pose of the ­present ­study was to ­describe and to com­pare iso­ki­netic ­strength pro­files (­peak ­torque, bilat­eral ­strength dif­fer­ences ­between D/ND leg (BD) and ham­strings/quad­ri­ceps (H/Q) ­ratio) in ath­letes of dif­ferent ­sports and posi­tional ­roles.
­Methods. ­Twenty-­eight ­elite vol­ley­ball ­players and 47 pro ­soccer ­players (goal­keepers, n=5; ­full-­backs, n=7; ­defenders, n=10; mid­fielders, n=15; for­wards, n=10) ­were eval­u­ated ­using an iso­ki­netic dyna­mom­eter (­Biodex-­System 2). Max­imal ­gravity cor­rected con­cen­tric ­peak ­torque of ­knee ­extensor and ­flexor mus­cles ­were meas­ured at ­angular veloc­ities of 360°.s-1 (6.28 rad•s-1) and 90°.s-1 (1.57 rad.s-1).
­Results. No sig­nif­i­cant BD ­were ­found ­between ­soccer and vol­ley­ball ­players ­with excep­tion of ham­strings at 90°.s-1 (­soccer: 10.6±8.0% vs vol­ley­ball: 6.9±5.5%). The H/Q ­ratio was sig­nif­i­cantly ­lower in vol­ley­ball ­players at 90°.s-1 (D: ­soccer 57.4±6.7% vs vol­ley­ball 50.4±7.2%; ND: ­soccer: 56.1±8.2% vs vol­ley­ball: 50.5±6.4%). No sig­nif­i­cant dif­fer­ences ­were ­found for BD and H/Q ­ratio in ­soccer ­players of dif­ferent posi­tional ­roles.
Con­clu­sion. In gen­eral, ­soccer and vol­ley­ball ­players do not ­seem to be dif­ferent con­cerning BD ­although a sig­nif­i­cant dif­fer­ence was ­observed in ham­strings at 90°.s-1. More­over, our ­data sug­gest ­that spe­cific ­demands of ­these ­sports and the dif­ferent posi­tional ­roles in ­soccer did not ­induce bilat­eral leg imbal­ances. How­ever, ­sport ­demands ­seem to influ­ence iso­ki­netic con­cen­tric H/Q ­ratio.