Myofascial trigger points contribute significantly to musculoskeletal pain and motor dysfunction and may be associated with accelerated muscle fatiguability. The aim of this study was to investigate the electrically induced force and fatigue characteristics of muscle taut bands in rats.
Methods
Muscle taut bands were dissected out and subjected to trains of electrical stimulation. The electrical threshold intensity for muscle contraction and maximum contraction force (MCF), electrical intensity dependent fatigue and electrical frequency dependent fatigue characteristics were assessed in three different sessions (n=10 each) and compared with non-taut bands in the biceps femoris muscle.
Results
The threshold intensity for muscle contraction and MCF at the 10th, 15th and 20th intensity dependent fatigue stimuli of taut bands were significantly lower than those of non-taut bands (all p<0.05). The MCF at the 15th and 20th intensity dependent fatigue stimuli of taut bands were significantly lower than those at the 1st and 5th stimuli (all p<0.01). The MCF in the frequency dependent fatigue test was significantly higher and the stimulus frequency that induced MCF was significantly lower for taut bands than for non-taut bands (both p<0.01).
Conclusions
The present study demonstrates that the muscle taut band itself was more excitable to electrical stimulation and significantly less fatigue resistant than normal muscle fibres.
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References
1.
SimonsD.G.Review of enigmatic MTPs as a common cause of enigmatic musculoskeletal pain and dysfunction. J Electromyogr Kinesiol2004; 14: 95–107.
2.
FallaD., LindstrømR., RechterL.Effect of pain on the modulation in discharge rate of sternocleidomastoid motor units with force direction. Clin Neurophysiol2010; 121: 744–53.
3.
MaquetD., CroisierJ., DupontC.Fibromyalgia and related conditions: electromyogram profile during isometric muscle contraction. Joint Bone Spine2010; 77: 264–7.
4.
GeH.Y., NieH.L., Graven-NielsenT.Descending pain modulation and its interaction with peripheral sensitization following sustained isometric muscle contraction in fibromyalgia. Eur J Pain2012; 16: 196–203.
5.
GandeviaS.C.Spinal and supraspinal factors in human muscle fatigue. Physiol Rev2001; 81: 1726–71.
Arendt-NielsenL., ZwartsM.Measurement of muscle fiber conduction velocity in humans: techniques and applications. J Clin Neurophysio1989; (12): 173–90.
8.
MademliL., ArampatzisA.Effect of voluntary activation on age-related muscle fatigue resistance. J Biomech2008; 41: 1229–35.
9.
ChenQ., BensamounS., BasfordJ.R.Identification and quantification of myofascial taut bands with magnetic resonance elastography. Arch Phys Med Rehabil2007; 88: 1658–61.
10.
SikdarS., ShahJ.P., GebreabT.Novel applications of ultrasound technology to visualize and characterize myofascial trigger points and surrounding soft tissue. Arch Phys Med Rehabil2009; 90: 1829–38.
11.
SimonsD.G., StolovW.C.Microscopic features and transient contraction of palpable bands in canine muscle. Am J Phys Med1976; 55: 65–88.
12.
HongC-Z, TorigoeY., JenY.The localized twitch responses in responsive bands of rabbit skeletal muscle fibers are related to the reflexes at spinal cord level. J Musculoskelet Pain1995; 3: 15.
13.
KuanT.S., ChenJ.T., ChenS.M.Effect of botulinum toxin on endplate noise in myofascial trigger spots of rabbit skeletal muscle. Am J Phys Med Rehabil2002; 81: 512–20.
14.
HouC.R., ChungK.C., ChenJ.T.Effects of a calcium channelblocker on electrical activity in myofascial trigger spots of rabbits. Am J Phys Med Rehabil2002; 81: 342–9.
15.
KuanT.S., HongC.Z., ChenJ.T.The spinal cord connections of the myofascial trigger spots. Eur J Pain2007; 11: 624–34.
16.
HayashiK., OzakiN., KawakitaK.Involvement of NGF in the rat model of persistent muscle pain associated with taut band. J Pain2011; 12: 1059–68.
17.
HuangQ.M., YeG., ZhaoZ.Y.Myoelectrical activity and muscle morphology in a rat model of myofascial trigger points induced by blunt trauma to the vastus medialis. Acupunct Med2013; 31: 65–73.
18.
MarcilM., KarelisA.D., PéronnetF.Glucose infusion attenuates fatigue without sparing glycogen in rat soleus muscle during prolonged electrical stimulation in situ. Eur J Appl Physiol2005; 93: 569–74.
19.
WawrowP.T., JakobiJ.M., CavanaughJ.M.Fatigue response of rat medial longissimus muscles induced with electrical stimulation at various work/rest ratios. J Electromyogr Kinesiol2011; 21: 939–46.
20.
IbrahimM.Y., AshourO.M.Changes in nitric oxide and free radical levels in rat gastrocnemius muscle during contraction and fatigue. Clin Exp Pharmacol Physiol2011; 38: 791–5.
21.
RoJ.Y., CapraN., MasriR.Development of a behavioral assessment of craniofacial muscle pain in lightly anesthetized rats. Pain2003; 104: 179–85.
22.
GeH.Y., ZhangY., BoudreauS.Induction of muscle cramps by nociceptive stimulation of latent myofascial trigger points. Exp Brain Res2008; 187: 623–9.
HongC.Z.Pathophysiology of myofascialtrigger point. J Formos Med Assoc1996; 95: 93–104.
25.
LiL.T., GeH.Y., YueS.W.Nociceptive and non-nociceptive hypersensitivity at latent myofascial trigger points. Clin J Pain2009; 25: 132–7.
26.
HongC.Z., ChenJ.T., ChenS.M.Sensitive loci in a myofascial trigger point region are related to sensory nerve fibers. Am J Phys Med Rehabil1997; 76: 172.
27.
GerwinR.D., DommerholtJ., ShahJ.P.P.An expansion of Simons’ integrated hypothesis of trigger point formation. Curr Pain Headache Rep2004; 8: 468–75.
28.
GerwinR.D.The taut band and other mysteries of the trigger point: an examination of the mechanisms relevant to the development and maintenance of the trigger point. J Musculoskelet Pain2008; 15: 115–21.
29.
SchwarzP.B., YeeN., MirS.Noradrenaline triggers muscle tone by amplifying glutamate-driven excitation of somatic motoneurones in anaesthetized rats. J Physiol2008; 23: 5787–802.
30.
GeH.Y., NieH., MadeleineP.Contribution of the local and referred pain from active myofascial trigger points in fibromyalgia syndrome. Pain2009; 147: 233–40.
GerdleB., GronlundC., KarlssonS.Altered neuromuscular control mechanisms of the trapezius muscle in fibromyalgia. BMC Musculoskelet Disord2010; 11: 42–5.
33.
HoyleJ.A., MarrasW.S., SheedyJ.E.Effects of postural and visual stressors on myofascial trigger point development and motor unit rotation during computer work. J Electromyogr Kinesiol2011; 21: 41–8.
34.
SerraoM., Arendt-NielsenL., GeH.Y.Experimental muscle pain decreases the frequency threshold of electrically elicited muscle cramps. Exp Brain Res2007; 182: 301–8.
35.
ShahJ.P., DanoffJ.V., DesaiM.J.Biochemicals associated with pain and inflammation are elevated in sites near to and remote from active myofascial trigger points. Arch Phys Med Rehabil2008; 89: 16–23.
36.
DahlstedtA.J., KatzA., WesterbladH.Role of myoplasmic phosphate in contractile function of skeletal muscle: studies on creatine kinase-defi-cient mice. J Physiol2001; 533: 379–88.
