Comparison of Active Isolated Stretch and Post Isometric Relaxation for Hamstring Flexibility.
Comparison of Active Isolated Stretch and Post Isometric Relaxation for Hamstring Flexibility.
This study was intended to compare the immediate, short term and long term effects of active
 isolated stretch versus post isometric relaxation on hamstring flexibility in young healthy
 adults.35 students were assigned randomly into two groups with 17 and 18 in each group. Group
 A was given post isometric relaxation while Group B was Active isolated stretch. 22.2 year
 male and female students with tight hamstring were included while any neurological and
 orthopedic disorder were excluded. Active Isolated Stretch and Post Isometric Relaxation at
 baseline, after first and final exercise session were calculated immediate and short term
 effects while long term effects were calculated after two weeks of final session.
Hamstring muscle is present on posterior region of thigh starting from gluteal region and
 ending in popliteal fossa. Hamstring has three muscles biceps femoris, semitendinosus and
 semimembranosus causing flexion at knee joint and help in extension of thigh. Biceps femoris
 further consists of two heads (long and short head). Long head is supplied by tibial part of
 the sciatic nerve, while short head is supplied by the common peroneal part of the sciatic
 nerve. Muscles such as gastro-soleus, tibialis posterior, rectus femoris, iliopsoas, tensor
 fasica lata, the hamstrings and hip adductors are more likely to be tightened in lower limbs.
 Muscle tightness can cause the muscle shortness and does not allow full passive or active
 range of motion. Full active and passive range of motion is only achieved when muscle is
 flexible.

 Tightness of hamstring muscle can occur due to many reasons like injury to the muscle,
 prolonged sitting hours which are part of different jobs and educational setups. This
 tightness could lead to strain of the hamstrings, which is the most common occurring injury
 of the lower limbs. Moreover, hamstring tightness is also correlated with low back pain and
 lumbar dysfunction. Massage and stretching relax the tightened muscles but cannot normalize
 the tone or improve their coordination. To achieve this, investigator retrained muscle memory
 by actively using those respective muscles. Simple stretching of different muscle groups
 especially hamstrings has been found to improve the extensibility and length of shortened
 muscles.

 Additionally, muscle Energy Techniques (MET) and their related post-isometric relaxation
 techniques have demonstrated better results in improving flexibility of the tightened
 muscles. Muscle Energy Techniques are used in soft tissue pathologies in which the patient
 performs active muscle contraction in specific positions and in specific direction against a
 force applied by the therapist. The therapist guides and controls the movement with
 instruction. These are manual techniques that use contraction of the specific muscles and are
 found to be effective in increasing flexibility of the muscles and improving range of motion.
 The underlying mechanism through which improvement in extensibility and length occurs is yet
 unclear and thought to be attributed to both mechanical as well as neurological factors.
 Firstly MET techniques applied to increase extensibility of the muscles typically involves
 following steps: stretching the muscle to the limit of barrier or person's tolerance,
 secondly the person performs an active isometric contraction of the muscle being stretched
 against a controlled resistance provided by the therapist, additionally the person relaxes
 the muscle being stretched while the therapist continues holding the stretched position,
 furthermore the therapist takes up the new range produced by muscle and lengthens it up to a
 new barrier, and this whole procedure is repeated again according to defined guidelines. The
 MET techniques can be modified with variations in different components such as force of
 contraction, duration of the contraction, duration of the stretch and repetitions. This whole
 process results in increased range of motion and improves flexibility.

 Post Isometric Relaxation (PIR) is a type of MET that relaxes the tight muscles with
 avoidance of initiating stretch reflex. This in turn results in reduced spasm and improved
 ROM. The relaxation is induced due to isometric contraction of the muscles with facilitation
 and inhibition. Active Isolated Stretch (AIS) is another type of stretching in which specific
 movement is performed for a specific muscle with assistance from a therapist or self-assisted
 (with rope or a band) and those particular movements are repeated again and again to induce a
 relaxation phenomenon in muscles, fascia and connective tissues. In AIS, movements are
 monitored carefully to avoid producing any stretch reflex .

 A single blind randomized control study was done in Islamabad federal college Islamabad with
 the duration of 6 months from Jan 2018 to July 2018.the calculated sample size was 35
 students (17 in group A and 18 in group B) through open epi . Non probability random sample
 selection method was used on the behalf of inclusion and exclusion criteria. 22.2+ 2.02 year
 male and female students of DPT with tight hamstring were included while hamstring injury and
 any neurological or orthopedic disorder were excluded. The study was approved by the Ethical
 and Research Committee, and all participants signed the informed consents. Group A was given
 post isometric relaxation while Group B was given Active isolated stretch for a period of 3
 weeks. Outcome measures were assessed at baseline, after first and final exercise session to
 estimate immediate and short term effects while long term effects were calculated after two
 weeks of final session of interventions. Semi structured questionnaire was used for
 subjective and objective assessment. AKE score, sit and reach test score and Lower Extremity
 Functional Scale questionnaire was used to assess lower extremity functional activities. Sit
 and reach test was also used to measure hamstring length.
Inclusion Criteria:

 - Tight hamstring (Inability to achieve greater than 160° of knee extension with hip at 90°
 of flexion).

 Exclusion Criteria:

 -  Having hamstring injury in past 6 months

 -  Having any neurological or orthopedic disorder effecting low back and lower limbs.