Atypical hamstrings electromyographic activity as a compensatory mechanism in anterior cruciate ligament deficiency

Abstract

Anterior cruciate ligament (ACL) deficiency may cause functional instability of the knee (noncopers), while other patients compensate and perform at the same level as before injury (copers). This pilot study investigated whether there is a compensatory electromyographic (EMG) activity of the hamstrings in copers, noncopers and control patients. Ten patients with an ACL deficiency were equally divided into two groups of copers and noncopers. All patients underwent gait analysis with EMG of six muscles around the knee. Ten healthy young men formed the control group. In contrast to noncopers, copers showed an atypical semitendinosus activity during stance phase; the corresponding trend was found in biceps femoris activity. There was no difference between copers and controls in knee extension during stance phase. The noncopers had less knee extension. Atypical hamstring muscle activity may thus be a compensatory mechanism by which copers enable themselves to perform on a normal level.

Knee flexion during stair ambulation is altered in individuals with patellofemoral pain

“…A study that investigated gait compensations at multiple time points in individuals who underwent anterior cruciate ligament reconstruction concluded that gait adaptations take a relatively long time to develop 1131. Furthermore, it is has been shown that patients with persistent symptoms have abnormal gait kinematics [3,5]. In the present study, gait adaptations during stair descent were more likely to occur when the current symptoms had been present for longer.…”

A 10-Year Prospective Trial of a Patient Management Algorithm and Screening Examination for Highly Active Individuals with Anterior Cruciate Ligament Injury

“…[35][36][37] Conversely, potential copers have movement patterns that are intermediate to uninjured subjects and noncopers. 13 Because inclusion of both groups in the same sample may obscure genuine differences, investigators evaluating movement patterns after ACL injury have used the classification algorithm to identify a homogenous subject population.1 , 2,9,12,14,26 The classification algorithm has not, however, had an impact on clinical practice patterns in the United States. Early surgical reconstruction continues as the standard of care for the highly active individual who exhibits an increase in anterior tibia translation after ACL injury.…”

Speed dependence of averaged EMG profiles in walking

“…(7)). The availability of normal EMG profiles, closely matched to the actual walking speed, can be helpful in discriminating between normal and abnormal profiles in clinical studies [10]. The only study, to our knowledge, in which EMG profiles have been recorded for a range of speeds is from Nilsson et al [11] who recorded over a wide range of speeds of 0.4-3 ms − 1 for walking and 1.0-9 ms − 1 for running.…”