A task failure has no effect on the electromechanical delay of the peroneus longus.
OBJECTIVE
Ankle inversion injuries represent the most common trauma sustained by athletes. Muscle fatigue from activity may contribute to a delay in the response of the ankle proprioceptors and dynamic restraints during unexpected inversion. The purpose of this investigation was to determine if the electromechanical delay (EMD) of the peroneus longus is influenced by a task failure exercise.


METHODS
Sixteen subjects (age 20 +/- 1.1 y; mass 71.6 +/- 12.5 kg; height 173.0 +/- 8.7 cm; 9 male, 1 female) with no lower extremity injuries reported for data collection.


METHODS
Data were collected from each subject's dominant leg using surface electromyography (EMG). Electrodes were applied over the peroneus longus (PL) using a standard protocol. A stimulating electrode was applied to the common peroneal nerve. Subjects were placed in a monopedal stance on a force platform. A low amplitude, short duration stimulus was applied to the common peroneal nerve. The EMG was used to determine timing of the M wave and the force platform was used to determine the onset of foot pronation. Once 6 trials were recorded, subjects completed 2 sets of an isotonic activity that isolated the peroneals. The task was completed to failure for each set. Immediately following the task failure exercise, subjects returned to the force platform for 6 additional trials recorded as before. Analysis of data was performed by determining the onset of the M wave as the beginning of positive EMG activity following the end of the imposed stimulus response. This point was superimposed on the force platform curve and the point at which a 10 N.m force change occurred was used to calculate the EMD (time difference between the force platform indicator and the M wave indicator).


RESULTS
Average EMD prior to the task failure exercise was 13.35 +/- 3.47 ms. Following the task failure exercise, the average EMD was 12.67 +/- 3.86 ms. A paired samples t test revealed no significant differences with regard to EMD between pre- and post-task failure exercise for the PL (p = 0.448).


CONCLUSIONS
We concluded that the task failure exercise did not affect the electromechanical delay of the PL.
McLoda
T A
TA
School of Kinesiology and Recreation, Illinois State University, Normal, Illinois 61790-5120, USA. tamcloda@ilstu.edu
Stanek
J M
JM
Hansen
A J
AJ
McCaw
S T
ST
D016512:Ankle Injuries / Q000503:physiopathology; D000843:Ankle Joint / Q000294:innervation / Q000502:physiology*; D004576:Electromyography; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D007551:Isotonic Contraction / Q000502:physiology; D008297:Male; D018763:Muscle Fatigue / Q000502:physiology*; D010543:Peroneal Nerve / Q000502:physiology*; D011434:Proprioception / Q000502:physiology; D016059:Range of Motion, Articular / Q000502:physiology; D013710:Tendons / Q000294:innervation / Q000502:physiology*; D055815:Young Adult