Effects of prolonged vibration to vastus intermedius muscle on force steadiness of knee extensor muscles during isometric force-matching task

https://doi.org/10.1016/j.jelekin.2016.09.002Get rights and content

Abstract

Afferent inputs from Ia fibers in muscle spindles are essential for the control of force and prolonged vibration has been applied to muscle-tendon units to manipulate the synaptic input from Ia afferents onto α-motor neurons. The vastus intermedius (VI) reportedly provides the highest contribution to the low-level knee extension torque among the individual synergists of quadriceps femoris (QF). The purpose of the present study was to examine the effect of prolonged vibration to the VI on force steadiness of the QF. Nine healthy men (25.1 ± 4.3 years) performed submaximal force-matching task of isometric knee extension for 15 s before and after mechanical vibration to the superficial region of VI for 30 min. Target forces were 2.5%, 10%, and 30% of maximal voluntary contraction (MVC), and force steadiness was determined by the coefficient of variation (CV) of force. After the prolonged VI vibration, the CV of force at 2.5%MVC was significantly increased, but CVs at 10% and 30%MVCs were not significantly changed. The present study concluded that application of prolonged vibration to the VI increased force fluctuations of the QF during a very low-level force-matching task.

Introduction

It is important that the relation between the capacity to maintain steady force during submaximal contractions and postural stability or mobility. Force steadiness has thus been used as an index to study adaptations in neuro-motor control (Clark et al., 2007, Durbaba et al., 2013, Enoka et al., 1999, Shinohara et al., 2003, Tracy and Enoka, 2002). In a single-agonist system, timing and variability in motor unit discharges determine the force fluctuation (Moritz et al., 2005). The activation profile of synergistic muscles affects the fluctuations in joint torque, which involve the summation of force fluctuations from several individual muscles (Shinohara et al., 2009). The activation pattern of individual synergists would therefore affect the force steadiness of multiple-agonists muscles.

The quadriceps femoris (QF) muscle group is well known to play an essential role as an anti-gravity muscle in daily physical activities. The vastus intermedius (VI) muscle occupies 30% of the volume of QF muscles (Akima et al., 2007, O’Brien et al., 2010). Given that muscle volume is the major determinant of torque capacity (Fukunaga et al., 2001), the VI muscle could jointly account for about one-third of the torque generated in the knee. However, during isometric low-level torque generation, VI contributed up to 50% of knee extension torque from the QF (Zhang et al., 2003). A study of amputated limbs has also identified VI as the most efficient synergist among individual QF muscles in extension of the cadaveric knee (Lieb and Perry, 1968). From these previous reports, the VI during low-level contraction would represent a significant contributor to torque-generation among the four QF synergists.

When we attempt to match a target during steady low-level contraction, afferent inputs from group Ia fibers in muscle spindles are essential for the control of muscle force (Freund, 1983, Kakuda et al., 1996, Shinohara, 2005). Prolonged mechanical vibration has been applied to muscle-tendon units to amend the excitatory synaptic input from Ia afferents to α-motor neurons (Fry and Folland, 2014, Kouzaki et al., 2000, Roll et al., 1989, Shinohara, 2005, Yoshitake et al., 2004). The vibration technique could induce selective attenuation of Ia afferent fibers originating from the vibrated muscle and tendon (Jackson and Turner, 2003, Kouzaki et al., 2000, Saito et al., 2016, Shinohara, 2005). Prolonged patellar tendon vibration did not change fluctuations of knee extensor force during a force-matching task (Saito et al., 2016). However, the effects of prolonged vibration to a synergist muscle on force steadiness during steady contraction are still unclear.

The purpose of the present study was to examine the effect of prolonged vibration to the VI muscle on the force steadiness of knee extensors during a force-matching task. We hypothesized that prolonged vibration to the VI increases force fluctuations in the knee extensor muscles during an isometric force-matching task.

Section snippets

Participants

Nine healthy men provided written informed consent to participate in the present study after receiving an explanation of the procedure, purposes, risks, and benefits associated with the study. Mean ± standard deviation (SD) age, height, and weight of the participants were 25.1 ± 4.3 years, 174.1 ± 5.3 cm and 73.5 ± 8.0 kg, respectively. The Ethics Committee for the Research Center of Health, Physical Fitness & Sports at Nagoya University approved the experimental protocols, which were conducted in

Electrical stimulation

Twitch force before the prolonged vibration was 163.3 ± 37.2 N. Twitch force after the prolonged vibration was 168.1 ± 51.0 N, showing no significant difference (P = 0.44). Maximal M-wave amplitudes of the VI were 3.9 ± 1.1 mV and 3.8 ± 1.0 mV before and after the vibration, respectively. Those of the VL were 6.5 ± 2.2 mV and 7.0 ± 2.8 mV before and after the vibration, respectively. Again, no significant differences were apparent (VI, P = 0.76; VL, P = 0.21).

Under the control condition, twitch force did not differ

Discussion

The purpose of present study was to examine the effect of prolonged vibration to the VI on the force steadiness of knee extensor muscles during force-matching tasks. The main findings were that application of prolonged vibration to VI significantly increased fluctuations in knee extensor force at 2.5%MVC, but not at 10% or 30%MVC. This result partly supports our hypothesis that prolonged vibration to the VI increases force fluctuations in knee extensor muscles during isometric force-matching

Conflict of interest

The authors declare that they have no conflict of interest.

Acknowledgements

The present study was supported in part by a Grant-in-Aid for Japan Society for the Promotion of Science (#25-860) to AS, and a Grant-in-Aid for Scientific Research (B) from the Ministry of Education, Culture, Sports, Science, and Technology Grant (#23300239) to HA.

Akira Saito received the Master of Arts degree in 2012 and Ph.D. degree in 2015 from Nagoya University. He was working as a research fellow of Japan Society for the Promotion Science from 2013 until 2015. He is working at the Faculty of Sport Sciences, Waseda University, as a Research Associate. His research interests focus on neuromuscular activation during movements in human.

References (39)

  • B.C. Clark et al.

    Effect of prolonged unweighting of human skeletal muscle on neuromotor force control

    Eur. J. Appl. Physiol.

    (2007)
  • R. Durbaba et al.

    The effects of isometric resistance training on stretch reflex induced tremor in the knee extensor muscles

    J. Appl. Physiol.

    (2013)
  • M.M. Ekblom et al.

    Effects of prolonged vibration on H-reflexes, muscle activation, and dynamic strength

    Med. Sci. Sports Exerc.

    (2011)
  • D. Farina et al.

    The extraction of neural strategies from the surface EMG

    J. Appl. Physiol.

    (2004)
  • J.P. Folland et al.

    The influence of maximal isometric activity on twitch and H-reflex potentiation, and quadriceps femoris performance

    Eur. J. Appl. Physiol.

    (2008)
  • H.J. Freund

    Motor unit and muscle activity in voluntary motor control

    Physiol. Rev.

    (1983)
  • A. Fry et al.

    Prolonged infrapatellar tendon vibration does not influence quadriceps maximal or explosive isometric force production in man

    Eur. J. Appl. Physiol.

    (2014)
  • T. Fukunaga et al.

    Muscle volume is a major determinant of joint torque in humans

    Acta Physiol. Scand.

    (2001)
  • L. Griffin et al.

    Motor unit firing variability and synchronization during short-term light-load training in older adults

    Exp. Brain Res.

    (2009)
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    Akira Saito received the Master of Arts degree in 2012 and Ph.D. degree in 2015 from Nagoya University. He was working as a research fellow of Japan Society for the Promotion Science from 2013 until 2015. He is working at the Faculty of Sport Sciences, Waseda University, as a Research Associate. His research interests focus on neuromuscular activation during movements in human.

    Ryosuke Ando received the Master of Arts degree in 2013 and Ph.D. degree in 2016 from Nagoya University. He is working as a research fellow of Japan Society for the Promotion Science from 2015. He was working at Edith Cowan University, Australia as a visiting researcher in 2013 and 2015. His research interest is anatomical properties of the thigh muscles using ultrasonography and muscle fatigue using electromyography.

    Hiroshi Akima received the M.Sc. degree in 1993 and Ph.D. degree in 1996 from the University of Tsukuba. Since 2002, he has been working at the Research Center of Health, Physical Fitness & Sports, Nagoya University, as a Professor. His research interest is neuromuscular control of human movements. He is also interested in age-related change in intramuscular adipose tissue evaluated by non-invasive techniques such as 1H MRS, MRI and ultrasonography.

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