Cerebral palsy (CP) is a disorder affecting movement, resulting from permanent damage to posture and motor development during fetal or infant brain development, caused by non-progressive disturbances. CP affecting about 1 in 500 children with an estimated prevalence of 17 million people worldwide. In CP, spasticity is often regarded to be the most common motor impairment. Spastic cerebral palsy stands out as the predominant subtype, constituting 77% of all cases, with bilateral spastic cerebral palsy dominating the spastic group (70%). Spasticity is only one of several components of the upper motor neuron (UMN) syndrome. Spasticity is a form of hypertonia due to hyperexcitable tonic stretch reflexes. Adult CP reported that 77% of CP children were having problems with spasticity. Hypertonicity resulting in abnormal movement patterns in both gross motor function and manual abilities in the children with CP.

Traditionally the treatment of tightness in children with spasticity has consisted primarily of techniques which involve static stretching, strengthening of the antagonistic muscles, use of orthosis and postural education etc. Some authorities also recommend Myofascial release to cause elongation of the spastic muscle with a component of tightness. Myofascial therapy can be defined as "the facilitation of mechanical, neural and psycho physiological adaptive potential as interfaced by the myofascial system". Akta Bhalara et al (2014) concluded in a study that myofascial release is effective in reducing spasticity in children suffering from spastic diplegic cerebral palsy. A study conducted in 2018 proved that myofascial release is effective in reducing spasticity of hamstring muscle and improves range of motion in spastic diplegic cerebral palsy. Ujwal Bhattacharya et al (2017) in a study concluded that MFR and passive stretching is effective in reducing spasticity and improving range of motion in spastic diplegic Cerebral Palsy.

Fred Mitchell first described MET in 1948 as a type of osteopathic manipulative diagnosis and treatment, primarily utilized to address somatic dysfunction, particularly issues such as reduced range of motion, muscular hypertonicity, and pain. MET involves the use of two physiological phenomena: Post Isometric Relaxation and Reciprocal Inhibition. Post Isometric Relaxation is a technique that was later developed by Karel Lewitt . Post Isometric Relaxation (PIR) is the effect of the decrease in muscle tone in a single or group of muscles, after a brief period of submaximal isometric contraction of the same muscle.

Preeti Gazbare et al ( 2018) conducted a Comparative Study On The Effect of Myofascial Release Over Post Isometric Relaxation On Calf Muscle Tone in Spastic Diplegic Cerebral Palsy and concluded that both MFR and PIR are equally effected in reducing calf muscle tone in spastic Cerebral Palsy. PIR improves better flexibility and decrease tightness of hamstring muscle as compared to static stretching. MET improves the independent mobility of stroke patients with hemiplegia enhances balance and stability. Janstephan T (2015) conducted a study to evaluate the effectiveness of neurodevelopment therapy with post isometric relaxation for lower extremity to improve functional ability in children with spastic diplegic cerebral palsy. The result suggested that neurodevelopmental therapy along with muscle energy technique improved the functional ability in children with spastic diplegic cerebral palsy.

Post Facilitation Stretch (PFS) is a technique developed by Janda.This technique is more aggressive than PIR but is also based on the concept of autogenic inhibition. Post facilitation stretching is a MET technique which uses postisometric relaxation. The term refers to the effect of the subsequent relaxation experienced by a muscle after an isometric contraction has been performed. The effect of a sustained contraction on the Golgi tendon organs seems pivotal, since their response to such a contraction seems to be set the tendon and the muscle to a new length by inhibiting it. A study concluded that Post Facilitation Stretching is effective in increasing Flexibility of tight hamstring muscles. A study concluded that post facilitation stretch is effective in reducing pain and improving muscle length. A study in published in 2024 compared the effect of the muscle energy technique (MET) and stretching technique on ankle dorsiflexion passive range of motion, balance, and gait ability of stroke patients with limited ankle dorsiflexion. And concluded that MET and Stretching both are effective in improving range of motion , balance and gait ability of stroke patients with limited ankle dorsiflexion.

The rationale for this study is that Post-facilitation stretch relaxation (PFSR) is proposed as an effective intervention for reducing lower limb spasticity in spastic cerebral palsy. By combining passive stretching with relaxation techniques post- facilitation, PFSR aims to decrease muscle tone and improve range of motion. This approach is individualized, often integrated with other therapies, and emphasizes patient education for long term management.