Quadriceps Atrophy after Knee Traumatisms and Immobilization: Electrophysiological Assessment

Abstract

Automatic analysis of EMG (T/A analysis) and invasive muscle fiber conduction velocity in situ (MFCV) were performed in 15 patients after traumatic lesions of the knee and immobilization with quadriceps atrophy. T/A analysis showed transient reduced number of turns, consistent with inhibition of quadriceps motoneurons, that recovered within the first 2 weeks after the plaster cast had been removed. MFCV was significantly slowed and showed a gradual improvement, reaching normal values after 6 weeks. These results suggest that decrement in activated motor units may be the cause of the disproportionate weakness of the quadriceps muscle on the first days after immobilization by the plaster cast. The recovery of MFCV was related with functional improvement of strength after the first weeks.

Histological Skeletal Muscle Damage and Surface EMG Relationships Following Eccentric Contractions

“…Specifically, muscle biopsies require surgical intervention, and the small tissue specimens obtained are not very likely to be representative of the whole muscle. In contrast, analysis by surface electromyography is noninvasive, and its signals have been used to evaluate, for example, muscle fatigue [4][5][6][7] and neuromuscular diseases [8,9]. Human studies have found that the characteristics of surface EMG signals are modified by EC [10][11][12][13][14][15].…”

Effect of Age and Gender on Muscle Function-Analysis by Muscle Fiber Conduction Velocity-

“…In human tests 3) , MFCV in the affected limb of patients with disuse atrophy of the quadriceps femoris due to osteoarticular disease was delayed compared with the intact side. MFCV in atrophied muscle due to denervation also reportedly showed delays, but recovered on reinnervation 4) , and MFCV in the atrophied muscle due to CNS paralysis showed delays 5 ) that improved with increased cross-sectional area of muscle during rehabilitation 6) .…”

“…Most papers have reported that differences by gender are observed in diameter of muscle fibers. However, regarding the ratio of Type I and II fibers in quadriceps femoris, one report indicated that females display a higher ratio of Type I fibers 27) , another showed that males display a higher ratio of Type I fibers 30) , and a third report found no gender differences 3) . This may indicate that no clear differences by gender exist.…”

Daily muscle vibration amelioration of neural impairments of the soleus muscle during 2weeks of immobilization

“…The reduction of EMG without the changes in Mmax suggested the occurrence of neural adaptations as a result of short-term immobilization (Cruz-Martinez et al, 2000;Deschenes et al, 2002;Gondin et al, 2004;Hortobagyi et al, 2000;Kaneko et al, 2003). Such adaptations within the nervous system may be ascribed to changes occurring at the spinal and/or supraspinal level.…”

“…However, a number of problems, such as reductions in muscle mass, strength, and motor performance (Berg and Tesch, 1996;Duchateau, 1995;Kawakami et al, 2001;Seki et al, 2001) can emerge from this form of treatment. Although the mechanisms involved in the negative adaptations are caused by a variety of factors, reduced neural drive of the muscle from the central nervous system (Cruz-Martinez et al, 2000;Deschenes et al, 2002;Gondin et al, 2004;Hortobagyi et al, 2000;Lundbye-Jensen and Nielsen, 2008a;Miles et al, 1994;Seki et al, 2007) seems to play a determinant role in the early stages of immobilization. Some studies have also reported that neural changes also account for the majority of the recovery in muscle motor performance following immobilization Stevens et al, 2006;Vandenborne et al, 1998).…”