Comparison of Active Isolated Stretch and Post Isometric Relaxation for Hamstring Flexibility.
Condition: Hamstring Tightness
Study type: Interventional

Summary: 
      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.
    

Detailed description: 
      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.
    

Intervention name(s): Active Isolated Stretch; Post Isometric Relaxation
Intervention type(s): Other; Other
Intervention description(s): In supine position, participant was asked to lock the knee and slowly lift leg using the quadriceps muscles. gentle assistance was given by the rope at the end of the movement, as the quadriceps muscles continue to move the leg. strech was applied for 2 sec and then release to starting position. two sets of 10 repetitions were performed.; In supine line, participant was asked to do SLR until resistance was met in hamstring muscles and then was asked to do isometric contraction (10-20% of maximum) for 5 - 10 sec and inhale. After this, patient was asked to exhale while doing so gentle stretch was applied till the new barrier. Starting from this new barrier, the procedure was repeated 2 - 3 times.
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Outcomes Assessor)
Primary purpose: Treatment
Keywords: Active isolated stretch; Active knee extension; Post isometric relaxation; Sit and reach test