How back-muscle fatigue influences lumbar curvature.

Context: Back-muscle fatigue and lumbar curvature are related to low back pain, but the relation between them is unknown.

Objective: To clarify whether lumbar curvature changes with back-muscle fatigue.

Design: Prospective pseudorandomized.

EMG Analysis of Lower Extremity Muscles in Three Different Squat Exercises.

The purpose of this study was to come across an exercise that increases the Hamstring contraction levels so that it may protect the anterior cruciate ligament (ACL). Previous studies have postulated that changing the projection of the center of gravity behind the feet will decrease the translation of the tibia, therefore protect the ACL. Muscle activity of the quadriceps, hamstring and soleus muscles in healthy subjects was measured with an EMG during three different squat tasks with differences of support of body weight and the center of gravity.

Electromyographic analysis of the knee during jump landing in male and female athletes.

Many noncontact anterior cruciate ligament (ACL) injuries in female athletes occur at foot strike during jump landing when the knee is extended. This study was undertaken to determine the activation level of the quadriceps and hamstring muscles electromyographically. Fifteen healthy volunteers (eight women and seven men), all of whom were collegiate basketball players, participated in the study.