A hamstring strain is caused by a rapid broad contraction or intense stretching of the hamstring muscle group, which results in high mechanical stress. This results in varying degrees of rupture within the fibers of the tendon unit.  Hamstring strains are not uncommon in sports activities Active athletes enjoy sprinting, jumping and touch sports, including Australian Rules Football (AFL) and American football, where short eccentric contractions are regular. They also have a re-injury rate, with as many as 1 in 3 hamstring accidents re-occurring, and Usually occurs within the first 2 weeks (Brukner and Khan 2017) [Hamstring accidents can also occur in recreational sports, including water skiing and bull riding, where the knee is fully elongated with force throughout the injury. ]
There are two main types of hamstring injuries:
Type 1 – Cause – High speed operation
Target – the long head of bicep femoris
May initially result in a noticeable loss of functionality
Quicker rehabilitation rate
Type 2 – Cause – Overlengthening
Target – free tendon proximal to the semimembranosus with pain near the ischial tuberosity and above the buttock.
Slightly longer rehabilitation
Askling protocol  – In their 2003 paper, Carl Askling and colleagues used 75 elite Swedish football players to evaluate specific hamstring rehabilitation protocols, called Protocol C and Protocol L. They then assessed the outcomes of return to play and re-injury. L agreement Targets eccentric loading of the hamstrings, while Protocol C includes traditional sports events for hamstring rehabilitation. Participants in the L-protocol were able to return to recreation faster than those in the traditional group (average 28 days vs. 52 days) sky). They are inconclusive about which protocols have been studied on the quality of sustained accidents, but researchers have been able to speculate that rehabilitation protocols such as eccentric exercise are more effective in getting athletes back into physical activity After a hamstring injury.
In these studies, the time from the date of injury (global rupture was ruled out) to the date of RP initiation was changed to five days per protocol, and no pain-inducing and/or analgesic medications were allowed at any time throughout the study recovery process. per RP Consists of 3 specific sporting events, all played in the sagittal plane. In each protocol, exercise 1 became a flexibility-specific exercise, 2 became a blend of strength and lumbopelvic control, and exercise 3 became a specific strength and cooking. 
In addition, it is recommended that hamstring injury rehabilitation programs should be prioritized based on strength and flexibility exercises that primarily involve high-load exercises of the longus tendon length
- THE EXTENDER (Flexibility)
- Starting position – Athlete lies supine, holds and stabilizes thigh of injured leg, hip flexed approximately 90°.
- INSTRUCTIONS – Athletes are instructed to perform slow knee extensions just before the pain point (3 sets x 12 reps x twice daily)
- Advanced: Increase speed or repetition
- Diver (hamstring strength and trunk stability)
- Starting Position – Athlete stands with full weight on injured leg, opposite knee slightly bent back.
- INSTRUCTIONS – Athletes are asked to perform the exercise in a simulated dive of the injured standing leg (hip flexion from an upright torso position) while simultaneously extending the arm forward and attempting maximal hip extension (3 sets X 6 repetitions X once per day), e.g. you try to parallel to the ground
- Premium ASIS/pelvis that stays level throughout movement
- Keep the standing leg bent at the knee 10-20°.
- Glider (specific eccentric strength exercise)
- Starting Position – Begin the exercise with the patient’s torso upright, grasping a support with one hand, and legs slightly apart. All weight should be on the heel of the injured leg with the knee bent approximately 10-20°. stand on a non-abrasive surface or use slider
- Instructions – Athletes are asked to perform a back glide exercise on the other leg and stop before pain develops. The return to the starting position should be done with the help of the arms and not the injured leg (3 sets X 6 reps X every three days)
- Progress by increasing glide distance and speed
- ↑ Sutton G. Hamstrung by hamstring strains: a review of the literature*.J Orthop Sports Phys Ther. 1984; 5(4):184-95. ↑
- ↑ Landry M. Brukner & Khan’s Clinical Sports Medicine. Physiotherapy Canada. 2014;66(1):109.
- ↑ Askling CM, Koulouris G, Saartok T, Werner S, Best TM. Total proximal hamstring ruptures: clinical and MRI aspects including guidelines for postoperative rehabilitation. Knee Surgery, Sports Traumatology, Arthroscopy. 2013 Mar;21(3):515-33.
- ↑ Wangensteen A, Askling C, Hickey J, Purdam C, Made AD, Thorborg K. Rehabilitation of hamstring injuries. InPrevention and Rehabilitation of Hamstring Injuries 2020 (pp. 225-270). Springer, Cham.
- ↑ Physiotutors. Askling Protocol | Hamstring Strain Rehabilitation. Available from: http://www.youtube.com/watch?v=D6bGLfCk4QU[last accessed 4/9/2022]