Peroneal Reaction Times and Eversion Motor Response in Healthy and Unstable Ankles.

OBJECTIVE: To measure and compare latency, electromechanical delay, and speed of motor response of the peroneus longus muscle in a large sample of subjects with healthy or unstable ankles. DESIGN AND SETTING: Subjects with healthy or unstable ankles underwent identical test procedures consisting of 6 consecutive, sudden 50 degrees ankle-inversion movements in the standing position with full weight on the tested leg. Latency, first and second decelerations, and total inversion time were monitored. In a separate setting, electromechanical delay was measured during a voluntary ankle eversion. SUBJECTS: We tested 81 subjects (27 males, 54 females) with healthy ankles or unilateral or bilateral ankle instability: 40 individuals with 48 unstable ankles (18 males, 22 females; age range, 18 to 23 years), and 41 individuals with 46 healthy ankles (9 males, 32 females; age range 15 to 29 years). MEASUREMENTS: Using surface electromyography, the latency of the peroneus longus muscle was measured during sudden inversion. Simultaneously, using accelerometry, first and second decelerations were measured. Separately, the electromechanical delay was measured using electromyography and accelerometry. RESULTS: The time of the first deceleration was significantly shorter in subjects with unstable ankles (25.5 milliseconds versus 28.4 milliseconds for those with healthy ankles). The latency, total inversion time, second deceleration time, and electromechanical delay were not shown to be significantly different between healthy and unstable ankles. CONCLUSIONS: The significantly shorter first deceleration during sudden inversion in the standing position in subjects with unstable ankles compared with subjects with healthy ankles is explained by less control of inversion speed in the first phase of the sudden inversion in unstable ankles. Our study does not confirm the results of the systematic literature search showing a longer latency in subjects with unstable ankles.

[1]  W. Duquet,et al.  Control of acceleration during sudden ankle supination in people with unstable ankles. , 2001, The Journal of orthopaedic and sports physical therapy.

[2]  D A Nawoczenski,et al.  Objective evaluation of peroneal response to sudden inversion stress. , 1985, The Journal of orthopaedic and sports physical therapy.

[3]  C. Johnson,et al.  Electromyographic response of peroneal muscles in surgical and nonsurgical injured ankles during sudden inversion. , 1993, The Journal of orthopaedic and sports physical therapy.

[4]  D. Rosenbaum,et al.  Peroneal reaction times for diagnosis of functional ankle instability , 2000 .

[5]  T S Buchanan,et al.  Ankle inversion injury and hypermobility: effect on hip and ankle muscle electromyography onset latency. , 1995, Archives of physical medicine and rehabilitation.

[6]  Gunnar Andreasson,et al.  The effect of external ankle support in chronic lateral ankle joint instability , 1992 .

[7]  Gordon Waddington,et al.  Discrimination of active plantarflexion and inversion movements after ankle injury. , 1999, The Australian journal of physiotherapy.

[8]  B. Beynnon,et al.  Electromyographic Latency Changes in the Ankle Musculature During Inversion Moments , 1996, The American journal of sports medicine.

[9]  J Kärrholm,et al.  Prolonged Reaction Time in Patients with Chronic Lateral Instability of the Ankle , 1995, The American journal of sports medicine.

[10]  Gunnar Andreasson,et al.  The Unstable Ankle: A Combined EMG and Biomechanical Modeling Study , 1992 .

[11]  D. Rosenbaum,et al.  Reliability of peroneal reaction time measurements. , 2000, Clinical biomechanics.

[12]  L. Konradsen,et al.  Proprioception at the ankle: the effect of anaesthetic blockade of ligament receptors. , 1993, Journal of Bone and Joint Surgery-british Volume.

[13]  M. Voigt,et al.  Ankle Inversion Injuries , 1997, The American journal of sports medicine.

[14]  G. Allison,et al.  Reliability of the Peroneal Latency in Normal Ankles , 1998, Clinical orthopaedics and related research.

[15]  G. Allison,et al.  Peroneal Latency in Normal and Injured Ankles at Varying Angles of Perturbation , 2000, Clinical orthopaedics and related research.

[16]  S M Lephart,et al.  The effect of sudden inversion stress on EMG activity of the peroneal and tibialis anterior muscles in the chronically unstable ankle. , 1997, The Journal of orthopaedic and sports physical therapy.

[17]  L. Konradsen,et al.  Ankle instability caused by prolonged peroneal reaction time. , 1990, Acta orthopaedica Scandinavica.

[18]  Eli Isakov,et al.  Response of the Peroneal Muscles to Sudden Inversion of the Ankle during Standing , 1986 .

[19]  W. Duquet,et al.  Static and Dynamic Roentgenographic Analysis of Ankle Stability in Braced and Nonbraced Stable and Functionally Unstable Ankles , 1998, The American journal of sports medicine.