TY - JOUR
T1 - Motor-neuron pool excitability of the lower leg muscles after acute lateral ankle sprain
AU - Klykken, Lindsey W.
AU - Pietrosimone, Brian G.
AU - Kim, Kyung Min
AU - Ingersoll, Christopher D.
AU - Hertel, Jay
N1 - Copyright:
Copyright 2017 Elsevier B.V., All rights reserved.
PY - 2011
Y1 - 2011
N2 - Context: Neuromuscular deficits in leg muscles that are associated with arthrogenic muscle inhibition have been reported in people with chronic ankle instability, yet whether these neuromuscular alterations are present in individuals with acute sprains is unknown. Objective: To compare the effect of acute lateral ankle sprain on the motor-neuron pool excitability (MNPE) of injured leg muscles with that of uninjured contralateral leg muscles and the leg muscles of healthy controls. Design: Case-control study. Setting: Laboratory. Patients or Other Participants: Ten individuals with acute ankle sprains (6 females, 4 males; age = 19.2 ± 3.8 years, height = 169.4 ± 8.5 cm, mass = 66.3 ± 11.6 kg) and 10 healthy individuals (6 females, 4 males; age = 20.6 ± 4.0 years, height = 169.9 ± 10.6 cm, mass = 66.3 ± 10.2 kg) participated. Intervention(s): The independent variables were group (acute ankle sprain, healthy) and limb (injured, uninjured). Separate dependent t tests were used to determine differences in MNPE between legs. Main Outcome Measure(s): The MNPE of the soleus, fibularis longus, and tibialis anterior was measured by the maximal Hoffmann reflex (Hmax) and maximal muscle response (Mmax) and was then normalized using the Hmax:Mmax ratio. Results: The soleus MNPE in the ankle-sprain group was higher in the injured limb (Hmax:M max = 0.63; 95% confidence interval [CI], 0.46, 0.80) than in the uninjured limb (Hmax:Mmax = 0.47; 95% CI, 0.08, 0.93) (t6 = 3.62, P = .01). In the acute anklesprain group, tibialis anterior MNPE tended to be lower in the injured ankle (Hmax:M max = 0.06; 95% CI, 0.01, 0.10) than in the uninjured ankle (H max:Mmax = 0.22; 95% CI, 0.09, 0.35), but this finding was not different (t6 = -2.01, P = .07). No differences were detected between injured (0.22; 95% CI, 0.14, 0.29) and uninjured (0.25; 95% CI, 0.12, 0.38) ankles for the fibularis longus in the ankle-sprain group (t6 = -0.739, P = .48). We found no side-to-side differences in any muscle among the healthy group. Conclusions: Facilitated MNPE was present in the involved soleus muscle of patients with acute ankle sprains, but no differences were found in the fibularis longus or tibialis anterior muscles.
AB - Context: Neuromuscular deficits in leg muscles that are associated with arthrogenic muscle inhibition have been reported in people with chronic ankle instability, yet whether these neuromuscular alterations are present in individuals with acute sprains is unknown. Objective: To compare the effect of acute lateral ankle sprain on the motor-neuron pool excitability (MNPE) of injured leg muscles with that of uninjured contralateral leg muscles and the leg muscles of healthy controls. Design: Case-control study. Setting: Laboratory. Patients or Other Participants: Ten individuals with acute ankle sprains (6 females, 4 males; age = 19.2 ± 3.8 years, height = 169.4 ± 8.5 cm, mass = 66.3 ± 11.6 kg) and 10 healthy individuals (6 females, 4 males; age = 20.6 ± 4.0 years, height = 169.9 ± 10.6 cm, mass = 66.3 ± 10.2 kg) participated. Intervention(s): The independent variables were group (acute ankle sprain, healthy) and limb (injured, uninjured). Separate dependent t tests were used to determine differences in MNPE between legs. Main Outcome Measure(s): The MNPE of the soleus, fibularis longus, and tibialis anterior was measured by the maximal Hoffmann reflex (Hmax) and maximal muscle response (Mmax) and was then normalized using the Hmax:Mmax ratio. Results: The soleus MNPE in the ankle-sprain group was higher in the injured limb (Hmax:M max = 0.63; 95% confidence interval [CI], 0.46, 0.80) than in the uninjured limb (Hmax:Mmax = 0.47; 95% CI, 0.08, 0.93) (t6 = 3.62, P = .01). In the acute anklesprain group, tibialis anterior MNPE tended to be lower in the injured ankle (Hmax:M max = 0.06; 95% CI, 0.01, 0.10) than in the uninjured ankle (H max:Mmax = 0.22; 95% CI, 0.09, 0.35), but this finding was not different (t6 = -2.01, P = .07). No differences were detected between injured (0.22; 95% CI, 0.14, 0.29) and uninjured (0.25; 95% CI, 0.12, 0.38) ankles for the fibularis longus in the ankle-sprain group (t6 = -0.739, P = .48). We found no side-to-side differences in any muscle among the healthy group. Conclusions: Facilitated MNPE was present in the involved soleus muscle of patients with acute ankle sprains, but no differences were found in the fibularis longus or tibialis anterior muscles.
KW - Arthrogenic muscle response
KW - Fibularis longus
KW - Hoffmann reflex
KW - Soleus
KW - Tibialis anterior
UR - http://www.scopus.com/inward/record.url?scp=79959573053&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=79959573053&partnerID=8YFLogxK
U2 - 10.4085/1062-6050-46.3.263
DO - 10.4085/1062-6050-46.3.263
M3 - Article
C2 - 21669095
AN - SCOPUS:79959573053
VL - 46
SP - 263
EP - 269
JO - Journal of Athletic Training
JF - Journal of Athletic Training
SN - 1062-6050
IS - 3
ER -