title: Force variability during isometric wrist flexion in highly skilled and sedentary individuals.
abstract: The association of expertness in specific motor activities with a higher ability to sustain a constant application of force, regardless of muscle length, has been hypothesized. Ten highly skilled (HS group) young tennis and handball athletes and 10 sedentary (S group) individuals performed maximal and submaximal (5, 10, 20, 50, and 75% of the MVC) isometric wrist flexions on an isokinetic dynamometer (Kin-Com, Chattanooga). The wrist joint was fixed at five different angles (230, 210, 180, 150, and 1300). For each position the percentages of the maximal isometric force were calculated and participants were asked to maintain the respective force level for 5 s. Electromyographic (EMG) activation of the Flexor Carpi Ulnaris and Extensor Digitorum muscles was recorded using bipolar surface electrodes. No significant differences were observed in maximal isometric strength between HS and S groups. Participants of HS group showed significantly (P < 0.05) smaller force coefficient of variability (CV) and SD values at all submaximal levels of MVC at all wrist angles. The CV and SD values remained unaltered regardless of wrist angle. No difference in normalized agonist and antagonist EMG activity was observed between the two groups. It is concluded that long-term practice could be associated with decreased isometric force variability independently from muscular length and coactivation of the antagonist muscles.
authors.affiliation: Laboratory of Neuromechanics, Department of Physical Education and Sport Science at Serres, Aristotle University of Thessaloniki, Thessaloniki, Greece.
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Salonikidis
authors.forename: Ioannis G
authors.initials: IG
authors.lastname: Amiridis
authors.forename: Nikolaos
authors.initials: N
authors.lastname: Oxyzoglou
authors.forename: Eduardo Saez Saez
authors.initials: ES
authors.lastname: de Villareal
authors.forename: Andreas
authors.initials: A
authors.lastname: Zafeiridis
authors.forename: Eleftherios
authors.initials: E
authors.lastname: Kellis
mesh_terms: D056352:Athletes; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology*; D008297:Male; D057185:Sedentary Behavior; D014953:Wrist / Q000502:physiology*; D055815:Young Adult