The hamstring muscles are very susceptible to tears and strains.
Hamstring strains are most common among sports that require rapid acceleration, deceleration, endurance and agility running at a high degree of speed, such as football, hockey, basketball, and tennis, such injuries can result in significant financial consequences to players and the clubs
Anatomy and biomechanics
A hamstring is a group of four muscles, three of which originate in common at the ischial tuberosity and attach distally to the knee. Semimembranosus and semitendinosus originate at the mid-portion of the ischial tuberosity and attach distally at the posteromedial tibia,
the long head of biceps femoris arises from both the lateral portion of the ischial tuberosity and the sacrotuberous ligament, and attaches distally at the head of the fibula, in common with the short head of biceps femoris. The short head of biceps femoris arises from the lateral inter-muscular septum and lateral femoral cortex at its distal third.
The multiple attachments of the hamstring allow this muscle to impact function throughout the pelvis and knees. In addition to flexion of the knee and extension of the hip, the hamstrings affect pelvic tilt.
The analyses of the running mechanism show that the maximal lengthening of the hamstring occurs at the end of the swing phase of the run, just prior to foot contact, the analysis confirms that the maximal hamstring contraction also correlates to this stage of the running phase, as the hamstrings decelerate the force of quadriceps and hip flexors.
Cause of the injury and risk factors
1. There are two different types of acute hamstring strains, one occurring during high-speed running and mainly involving the biceps femoris long head, the other during movements leading to an extensive stretch of the hamstrings such as reaching the tennis ball or defined the shuttle in badminton or sliding tackle and high kick in football, often involving the free proximal tendon of semimembranosus.
2. In addition, the muscle-tendon architecture may be a factor in the development of hamstring injuries.
3. Aponeurosis morphology of the biceps femoris long head may play a significant role in determining stretch distributions throughout the muscle.
4. Study shows that some of the mild hamstring injuries, often presenting as a ‘cramp’ or ‘twinge’ or ‘feeling of impending tearing’, is not due to a hamstring muscle injury, but due to referred pain from the lumbar spine, fascial injury or gluteal trigger points. Now with the advent of MRI showing minimal or no local muscle damage in these cases, the so-called MRI-negative hamstring injury, there has been the broader acceptance of this phenomenon and appropriate treatment initiated with resulting short recovery period
2. Imbalance in the strength between the quadriceps muscle and the hamstring muscles, the quadriceps are a very large, strong group of muscles that help to extend the leg. These muscles may forcibly overstretch the hamstring, placing excessive tension on the hamstring muscles.
5. The tightness of the iliopsoas is directly responsible for a relative anterior pelvic tilt that places the hamstring at a mechanical disadvantage by increasing the tension at the muscle when the end of the swing phase is reached
6. The weakness of the abdominal muscles allows an anterior pelvic tilt, placing the hamstrings at a mechanical disadvantage that can lead to overuse injury.
7. Increase age of the players has been shown to be associated with increased quadriceps and hip flexor tightness and increased body weight
8. Previous injury, which is consistently one of the highest predictors of subsequent injury risk.
9. Hamstring muscle fatigue which usually leads to poor neuromuscular control and poor muscles coordination
10. Inappropriate, inadequate warm-up, a warm-up must be active and dynamic including muscles stretch to prepare the muscles to the forces involved in the training or game
Signs and symptoms of a hamstring strain
Symptoms vary from mild to severe according to the degree of the strain
General, it can be summarized as the following
1. Tightness, low-grade ache of the muscles or sudden severe pain with snapping or popping feeling
2. Tenderness and bruises over the injured area
3. Walking difficulty
4. Inability to bend the knee or straight the leg arise
5. Palpable lump or gap in the muscles
6. Partial or complete loss of muscles function
Degrees of a hamstring strain
Ultrasound sound scan and MRI can identify the location and extent of injury
there are 3 degrees of muscles strain
• Grade 1 (mild): just a few fibers of the muscle are ruptured. This has a minor effect on the muscle's power and endurance. Patients' complaints are stiffness on the side of the injury. Patients can walk normally with slight discomfort during SLR, and isometric hamstring contraction, recovery period 1-3 weeks
• Grade 2 (medium): approximately half of the fibers are torn. The patient complains are pain, swelling, skin bruises, and walking difficulty. Pain can be provoked by SLR and muscles isometric contraction, recovery period 4-8 weeks
• Grade 3 (severe): more than half of the fibers torn or complete rupture of the muscle. Both the muscle fibers and the muscle-tendon can suffer from this injury. the patient complains of pain, swelling, and massive skin bruises, the patient cannot walk, severe tenderness and loss of muscles function, recovery period 3-6 months
Physical treatment
Introduction to rehabilitation
The main objective of physical therapy and the rehabilitation is to restore the patient’s functions ability with minimal risk of recurrence.
Hamstring strain rehabilitation remain a challenge for both athletes and physiotherapist due to the rate of incidence, slow recovery and high rate of recurrence, studies shown that the use of eccentric strengthening exercises at long muscle had a positive effect.
On the other hand, a study tried to compare eccentric strengthening exercises with progressive agility and trunk stabilization exercises. The eccentric rehabilitation consisted of static stretching, isolated progressive hamstring resistance exercise, and icing vs progressive agility and trunk stabilization exercises and icing as treatment.
The study found a significantly better result in patients that were rehabilitated with progressive agility and trunk stabilization.
Deep stripping massage is another technique used as rehabilitation for hamstring strain injury. Most of the time it is combined with other rehabilitation techniques.
Functional dry needling is a technique that has been reported to be beneficial in the management of pain and dysfunction after muscle strains and in combination with an eccentric training program,
The impact of kinesiology tape has been demonstrated to be efficient at improving muscle flexibility, which can prevent or improve the risk of having injuries.
Kinesiology tape can be used in combination with other rehabilitation programs to improve muscle flexibility.
Neuromuscular control of the lumbar-pelvic region is needed to enable optimal functioning of the hamstrings during normal sporting activities.
The general goal of treatment:
1. Protect the healing
2. Control pain and swelling
3. Minimize the muscles wasting
4. Early regain the full range of motion
5. Gradually regain the muscles length
6. Gradually regain the muscles power
7. Progressive core and proximal stability exercise
8. Sport-specific and injury prevention program
General Rehabilitation:
• Ice therapy – 2-3 hours gap
• Compression wide bandage
• Pulsed ultrasound
• Electric muscles stimulation
• Hip and ankle stretching and strengthening
• Multi-angles Sub-maximal isometric strengthening within the limit of pain
• Single leg balance and single leg dead left
• Gentle Soft tissue mobs
• Progressive sciatic nerve flossing
• Progressive lumbar-pelvic neuromuscular control
• Pain-free isotonic knee flexion
• Progressive plyometric exercise
• Progressive eccentric exercise
• Sport-specific exercise
Example of a hamstring exercise
1. Gradually active straight leg raise within the limit of pain 5-time 3 sets
2. Gradually active knee extension 5-time 3 sets
3. Progressive bridging exercise 2legs then one leg in 30, 60, 90 angles 5 times 3 sets
5. Prone hamstring isometric exercise from 30,60 90 angle
6. Drinking Bird or diver
7. Asking glider exercise
8. Nordic hamstring exercise
9. Swiss ball hamstring curl 2 leg one leg
10. Hamstring deep stripping massage
11. Hamstring muscles progressive running technique
12. Hamstring plyometric exercise
Sport-specific exercise depends on the patient long term goal and types of function and sport
Return to normal daily life and return to sport criteria
1. No localized pain and discomfort in palpation, resisted hamstring contraction.
2. Pain-free straight leg raises in a full range of motion.
3. Pain and discomfort-free repeated spent and repeated lengthening test.
4. The normal ratio of quadriceps hamstring strength.
5. Performing the normal daily activity or sport-specific exercise pain and discomfort free 3-5 successive time before considering fully recover.
Conclusion
Hamstring mechanics are very complex, mechanism of injury and assessment of lumbar-pelvic biomechanics and function may play a role in the treatment and prevention of hamstring injury.
Efforts at management should incorporate proven standards of acute muscle injury care with rehabilitation efforts that consider the total activity-specific demands on the lower extremity and pelvic kinetics