Six subjects between the ages of 18 and 35 years old were examined to compare muscle use. The rectus abdominus, erector spinal, gluteus maximus, quadriceps, hamstring, gastrocnemius, and tibiallis anterior muscles were assessed by electromyogram. Conventional exercise was performed by weight lifting on quadriceps, hamstring, abdominal and back extension machines and then compared to low-impact ...

The purpose of this study was to demonstrate the respective activation of the biceps femoris (BF), semitendinosus (ST), and semimembranosus (SM) muscles during overground sprinting. Lower extremity kinematics and the electromyographic (EMG) activities of the BF, ST, and SM muscles were recorded for 13 male sprinters performing overground sprinting at maximum effort. Mean normalized EMG activity...

Dystrophin-deficient skeletal muscles of mdx mice undergo their first rounds of degeneration-regeneration at the age of 14-28 days. This feature is thought to result from an increase in motor activity at weaning. In this study, we hypothesize that if the muscle is prevented from contracting, it will avoid the degenerative changes that normally occur. For this purpose, we developed a procedure o...

In the surgery of cerebral palsy, tenotomy of the hamstrings near their insertion, with or without reinsertion into the femur, is an established and useful operation (Eggers 1952, Pollock and Sharrard 1958). Division of the tendinous origin of the hamstring muscles is not so well known. We have done this operation with considerable success when the quadriceps muscle is acting strongly and tight...

A patient with multiple sclerosis (MS) and severe osteoarthritis of the right knee with valgus deformity developed early in the postoperative period a posterior dislocation of the knee after total knee arthroplasty (TKA), due to severe spasm of her hamstring muscles. At revision surgery the posterior cruciate retaining prosthesis was exchanged for a non-linked constrained knee prosthesis. Techn...

BACKGROUND Patients with chronic injuries of the proximal hamstring can develop significant impairment because of weakness of the hamstring muscles, sciatic nerve compression from scar formation, or myositis ossificans. PURPOSE To describe the surgical outcomes of patients with chronic injury of the proximal hamstrings who were treated with hamstring repair and sciatic neurolysis supplemented...

This study evaluated gender differences in the magnitude and timing of hamstring and quadriceps activation during activities that are believed to cause anterior cruciate ligament (ACL) injuries. Twelve men (age = 21.0 +/- 1.2 years; body mass = 81.61 +/- 13.3 kg; and jump height = 57.61 +/- 10.15 cm) and 12 women (age = 19.91 +/- 0.9 years; body mass = 64.36 +/- 6.14 kg; and jump height = 43.28...

Br J Sports Med February 2012 Vol 46 No 2 88 The fi rst publications which considered the time of onset in the gait cycle for hamstring strains concluded that early stance was the highest risk period.1,2 The rationale proposed was that external joint moments were much higher in stance phases than swing (table 1) because of the presence of high hip and knee joint reaction forces secondary to the...

BACKGROUND Muscle bellies of the hamstring muscles are intimately associated with the sciatic nerve, putting the sciatic nerve at risk of injury associated with proximal hamstring avulsion. There are few data informing the magnitude of this risk, identifying risk factors for neurologic injury, or determining neurologic outcomes in patients with distal sciatic symptoms after surgery. PURPOSE T...

Background: Hamstring muscles contracture is a major problem in the management of the cerebral palsy CP patient causing the crouch gait which is one of the most resistant conditions to treat. Methods: Twenty patients (40 knees) with spastic cerebral palsy diaplegia, between 7 – 12 years of age, presented to The National Institute of Neuromotor System of Egypt, from January 2010 to January 2011....