Muscle Contraction Velocity: A Suitable Approach to Analyze the Functional Adaptations in Elite Soccer Players.
Tensiomyography (TMG) has been used as a simple and non-invasive tool to assess the mechanical properties of skeletal muscles. The TMG-derived velocity of contraction (Vc), which can be calculated from the ratio between maximal radial displacement and the sum of contraction time and delay time, has been proposed for evaluating athletes. However, its sensitivity to training effects and possible relation with changes in soccer players' neuromuscular performance have not yet been addressed. To test this possibility, twenty-two male Brazilian elite soccer players were assessed using TMG-derived Vc, unloaded squat jump, countermovement jump and drop jump at 45 cm, loaded jump squat and linear (20 m) and change of direction (COD) sprint tests, prior to and after an 8-week period, between two consecutive official tournaments, during which the concurrency between endurance and strength-power training commonly impairs neuromuscular capacities. Magnitude-based inference was used to detect meaningful training effects. From pre- to post-tests, it was observedlikelyto almost certainlyimprovements in all modes of jumping tests. In addition, we could verify decrements in the 20-m and COD sprint performances, which were rated asvery likelyandalmost certainly, respectively. Finally, both rectus femoris and biceps femoris muscles presented alikelyreduction in Vc. Therefore, chronic decreases in sprinting speed are possibly accompanied by a reduced TMG-derived Vc. From a practical standpoint, the TMG-derived Vc can be used to monitor negative specific-soccer training effects related to potential impairments in maximum speed.
NAR - Nucleus of High Performance in Sport, São Paulo, SP, Brazil; Department of Mechatronics Engineering, University of São Paulo, SP, Brazil.
Irineu
I
Loturco
NAR - Nucleus of High Performance in Sport , São Paulo, SP, Brazil.
Lucas A
LA
Pereira
NAR - Nucleus of High Performance in Sport , São Paulo, SP, Brazil.
Ronaldo
R
Kobal
NAR - Nucleus of High Performance in Sport , São Paulo, SP, Brazil.
Katia
K
Kitamura
Department of Physical Activity Sciences, Universidad de Los Lagos , Osorno, Chile.
Rodrigo
R
Ramírez-Campillo
Red Bull Brazil Football , São Paulo, SP, Brazil.
Vinicius
V
Zanetti
NAR - Nucleus of High Performance in Sport , São Paulo, SP, Brazil.
Cesar C Cal
CC
Abad
NAR - Nucleus of High Performance in Sport, São Paulo, SP, Brazil; Department of Physical Education, State University of Londrina, PR, Brazil.
Fabio Y
FY
Nakamura
Football; concurrent training; elite athletes; muscle function; muscle power