Saudi Journal of Sports Medicine

: 2020  |  Volume : 20  |  Issue : 1  |  Page : 6--12

Effect of proprioceptive neuromuscular facilitation stretching on functional reach of lower extremity using Y-balance test

Munazzah Orooj1, Supriya Awasthi1, Adil Ali Ansari1, Nida Imtiyaz2,  
1 Department of Physiotherapy, School of Allied Health Sciences, Sharda University, Greater Noida, Uttar Pradesh, India
2 Department of Physiotherapy, Teerthanker Mahaveer University, Moradabad, Uttar Pradesh, India

Correspondence Address:
Dr. Munazzah Orooj
Department of Physiotherapy, School of Allied Health Sciences, Sharda University, Greater Noida - 201 306, Uttar Pradesh


Objective: The aim of the study was to investigate the efficacy of proprioceptive neuromuscular facilitation (PNF) stretching in improving flexibility and functional reach of the lower extremity using Y-balance test (YBT) among amateur badminton players. Methods: Thirty male students (age 20 ± 1.8 years, height 162 ± 8.2 cm, weight 51 ± 9.2 kg, body mass index 20 ± 3.9 kg/m2) from Teerthanker Mahaveer University having hamstring tightness and without any musculoskeletal disorders formed the sample of this study. Subject's age, height, and weight were recorded. Informed consent was taken from all the subjects. The subjects were randomly assigned into two groups each consisting of 15 subjects. Hamstring flexibility for each group was measured using YBT. Subjects of the experiment group were treated with PNF stretching; stretch was performed three times a week for a total training period of 4 weeks. However, the subjects of control group were not subjected to any type of stretching. Results: The study results revealed a significant improvement in PNF stretching protocol compared to the control group. The findings of the study provide beneficial evidence that PNF stretching significantly improves flexibility and YBT performance among amateur badminton players. Conclusion: The study concludes that 4 weeks of PNF training in amateur badminton players has favorable changes in their functional reach, i.e., hamstring muscle when compared from pretest.

How to cite this article:
Orooj M, Awasthi S, Ansari AA, Imtiyaz N. Effect of proprioceptive neuromuscular facilitation stretching on functional reach of lower extremity using Y-balance test.Saudi J Sports Med 2020;20:6-12

How to cite this URL:
Orooj M, Awasthi S, Ansari AA, Imtiyaz N. Effect of proprioceptive neuromuscular facilitation stretching on functional reach of lower extremity using Y-balance test. Saudi J Sports Med [serial online] 2020 [cited 2021 Jul 30 ];20:6-12
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The muscle power of the lower limbs is known to be one of the most important factors that determine an athlete physical condition and performance.[1] Flexibility is defined as the range of motion available in the joint or group of joints, which is influenced by muscle tendon, ligaments, and bones. Limited flexibility has been shown to predispose a person to several musculoskeletal overuse injuries and significantly affect a person level of fitness.[2]

Muscle tightness is frequently postulated as intrinsic factors for the development of muscle injury. It has also been proven that muscle tightness is the main contributing factor, which will lead to the risk of pathological conditions of the knee and spine. Musculotendinous strains are one among the most prevalent as well as the most frustrating group of injuries for athlete and healthcare professionals. Maintaining normal muscle length requires regular strengthening to prevent muscle stiffness and benefits from decreased risk of musculoskeletal injuries and to enhance physical performance.[3]

Stretching is traditionally used a part of warm-up to increase the flexibility or pain-free range of motion around a joint in an attempt to promote better performance and/or decrease the risk of injury. Stretching technique is used in clinical practice to increase the flexibility with some support for their use.[4] Stretching techniques are categorized as static, ballistic, slow active, and proprioceptive neuromuscular facilitation (PNF).[5] Numerous investigations established PNF techniques as more efficacious treatments than traditional static stretching exercise for range of motion or flexibility enhancement.[6]

Sports such as badminton is individual, noncontact sports which requires a combination of jumps, lunges, quick changes in direction, and rapid arm movement. During such movements, the body may be exposed to various forms of injuries. The physical demands of badminton suggest that injuries to the limbs may be frequent occurrence. Soft tissue injuries to the lower limbs were the most frequent injuries among badminton players. The type of injury is often severe in character and demands a long period of treatment and rehabilitation.

PNF is a more advanced form of flexibility training that involves both stretching and contraction of the muscle group being targeted. While there are several variations of PNF stretching techniques based on Kebat's concept such as Hold relax, contract relax contract relax antagonist contract but in PNF stretching the muscular organelles called Golgi tendon organs (GTOs) and muscle spindle are targeted by stretch forces, specifically PNF patterns. GTOs are activated by passive or active tension in a muscle. Significant improvements have been noted in the hamstring flexibility when PNF stretching techniques are incorporated in comparison to slow stretch, ballistic stretch, and static stretch.[5]

Although flexibility being an essential fitness component, if gets decreased can lead to changes in joint function, postural alignment and can lead to complications like indirect impairment such as muscle tightness, atrophy, fibrosis, contracture, and postural abnormalities. At present, various interventions are available to increase flexibility of hamstring muscle.[7] However, there are not many studies that have analyzed the effect of PNF stretching on the functional reach of lower extremity using Y-balance test (YBT) among amateur badminton players.[8],[9]


Factors were two categories of training, namely experimental group and control group as depicted in [Flowchart 1].[INLINE:2]

Experimental approach to the problem

The study adopted a two-group, factor design in carrying out laboratory-based test to determine whether PNF training improves flexibility.


The volunteer participants were 30 collegiate athletes (15 females and 15 males) with a mean age of 20 ± 1.8 years, a height of 162 ± 8.2 cm, a weight of 51 ± 8.80 kg, and a 3–4 times weekly training at Teerthanker Mahaveer University, Moradabad, India.

Before the study commenced, two familiarization sessions were conducted to ensure that all the subjects were comfortable with the procedures. They were randomly assigned to experimental and control groups by a blinded researcher who was not associated with the study and advised to guarantee equal-group assignment in terms of gender. The purpose and procedures of the research were explained to the participants, and informed consent was obtained from them.

Sampling method

Simple random sampling.

Sample size

Thirty subjects.

Sample size calculation

The number of subjects was determined using computer software program G power 3.15 (Mannheim, Germany) using the data of previous “static stretching v/s hold relax (pnf) on sustainability of hamstring flexibility in sedentary living college students.”[2] Thirty subjects per group including 12% dropout were shown to be necessary on the effect size of 0.30, alpha level 0.05, and power (1-beta) of 0.80. Four additional participants were recruited to maintain sample size in the event of dropout or problem with data collection.

Sample population

Data were collected from amateur badminton players.

Inclusion criteria

Subjects aged 17–26 years (amateur badminton players); subjects ready to participate willingly; subjects with no other complication of upper/lower limbs fracture or dislocation post traumatically; and finally, subjects complaint with the training protocol.

Exclusion criteria

Subjects with any complaint of musculoskeletal conditions of upper/lower limbs bilaterally; subjects who had a history of fracture or dislocation of both extremities; subjects who had a history of trauma in both extremities; subjects who are suffering from neurological, cardiovascular, or other medical conditions.

Training procedure

Before the training, each subject underwent initial assessment. In the PNF group, PNF was applied by a trained therapist in two diagonals, with 8–10 repetitions, three times in a week for 4 weeks, respectively. Subjects lay on the unaffected side, while the therapist stood in the line of desired motion. First, therapist gave the preparatory instruction. In the beginning of the pattern, the therapist pulled the leg up in the elongated position and then gave instructions for desired position. Rhythmic initiation and repeated contraction facilitation technique were applied in all patients. The repeated contraction technique increases the active range of motion and guides the subject motion toward the desired motion. The rest interval between repetitions was 10 s, and the measurement was taken after 4 weeks.

The YBT was conducted according to a protocol. Barefoot participants started the YBT with six practice trails in each direction before they underwent the formal testing. The order of the practice was right anterior reach (six trails), left anterior reach (six trails), right posteromedial reach (six trails), left posteromedial reach (six trails), right posterolateral reach (six trails), and left posterolateral reach (six trails). The formal testing trails were performed in the same order as the practice trails, with three trails performed in each direction. In each trail, the participants were instructed to reach as far as they could by using their foot while keeping their reach indicator and then return to the starting point, while they maintain their balance on the stance limb. The maximum reach distance was recorded to the nearest centimeter in each trail. The maximum reach distance of the three formal trails in each direction was used for analysis.[10],[11]



The patient stands on one leg while reaching out in three different directions with the other lower extremity. They are anterior, posteromedial, and posterolateral. When using the Y-Balance Kit, the three reaches yield a “composite reach distance” or composite score to predict injury. Researches show that collegiate football players with a composite score below 89% had an increased probability of injury from 37.7% to 68%. Therefore, a cut point of 89% composite reach on the YBT was established.


The lower quarter Y-balance test (LQYBT) showed good intrarater test–retest reliability with an acceptable level of measurement error among multiple rates screening, while other study showed excellent reliability (ICC = 0.88–0.99).

Ethical clearance

The ethics committee approval was not obtained because the committee at the institution within which the work was undertaken did not exist when this study was started. Nevertheless, the research was conducted according to the highest ethical standards and conformed to the provision of the Declaration of Helsinki, 1995.

Outcome measure

Flexibility is defined as the range of motion available in the joint or group of joints that is influenced by muscle, tendon, ligaments, and bones.[12] Flexibility of hamstring has long been a concern of physical therapist and rehabilitation specialist, as well as physical educator and sport coaches. Increasing hamstring flexibility was reported to be an effective method for increasing hamstring muscle performance.

Data analysis

Data analysis was done using SPSS version 20, Armonk, New York, United state. The baseline criterion measures were compared between the groups and a mixed ANOVA design with group (intervention and control) was employed. A P < 0.05 was considered statistically significant.


The intervention group experiences clinically significant improvement in the right anterior, right posteromedial, right posterolateral, left anterior, left posteromedial, and left posterolateral after 4 weeks of PNF stretching, with significant difference between groups as shown in [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]. Of the 45 subjects screened for the study, 15 were excluded, 5 declined to participate, 5 did not meet the inclusion criteria, and 5 had other reasons for not participation (time availability, compliance issue); therefore, 30 students (mean age = 20.03 years) were allocated to the intervention (n = 15) and control (n = 15) group. Fifteen students completed posttest assessment and were included in the analysis. Baseline characteristics are provided in [Table 1]. No significant between-group difference was noted in the baseline characteristics or outcomes. The The intervention group experiences clinically significant improvement in the right anterior, right posteromedial, right posterolateral, left anterior, left posteromedial, and left posterolateral after 4 weeks of PNF stretching, with significant difference between groups (P < 0.05). as shown in [Table 2].{Figure 1}{Figure 2}{Figure 3}{Figure 4}{Figure 5}{Figure 6}{Table 1}{Table 2}


The present study is a randomized control trial to evaluate the effect of PNF stretching on improving functional reach among amateur badminton players. The YBT scale was used for finding the difference between two groups. The intervention group reported a clinically significant improvement in the right anterior, right posteromedial, right posterolateral, left anterior, left posteromedial, and left posterolateral after PNF stretching, with significant difference between groups (P < 0.05), whereas there was no clinical significant improvement in the control group. The two intervention groups received stretching program 3 days per week for 6 weeks, while control group did not receive any stretching. The results indicated that range of hip joint flexibility of both groups of static and PNF stretching increases (P < 0.05), while it remained unchanged in the control group subjects. The result of our study coincides with the study done by Lee et al., 2013 which showed that the experimental group which received PNF training showed statistically significant difference as compared to control group.[8] Another study done by Nagarwal et al. stated that PNF (hold relax) result in the improvement of hamstring flexibility and that it is helpful in using it in clinical practice for improving hamstring flexibility.[13]

The results of the present study partly corroborate the findings by Spernoga et al., 2001, who observed that the immediate gain of the hamstrings stretching only remains for 6 min, when it is not considered significant any longer.[14] To explain the loss of the immediate effect, it is known that besides the elastic effect of the muscular viscoelasticity, the relaxing after the stretching maneuver stimulates the effect of muscular tixotrophy which acts in the tissue shortening. Muscular tixotrophy is the result of an increase in the number of steady ligations between the actin and myosin, when the muscle is relaxing. Therefore, the muscle stiffness increases.[15] However, the result of the present study shows that even with a considerable loss of the immediate effect, 24 h after stretching, there is still gain in breadth; hence, at each day, a residual breadth gain is incorporated.

PNF stretching techniques suggest that autogenic inhibition of the stretched muscle provides increase in range of motion. Autogenic inhibition was defined as the inhibition of the homonymous muscle alpha motor neurons by the stimulation of the Golgi tendon organ. This inhibitory effect is thought to diminish muscle activity and therefore allow for relaxation so that the muscles can be stretched. Motor pool excitability significantly diminished after the PNF stretching.[16] Flexibility is an important physiological component of physical fitness, and reduced flexibility can cause inefficiency in the workplace and is also a risk factor for low back pain. Increasing hamstring flexibility was reported to be an effective method for increasing hamstring muscle performance.[17],[18]

The LQYBT has been suggested as a return-to-play tool for amateur badminton players with less hamstring flexibility. In addition, difference in scores between sides or between pre- and post-testing can indicate higher susceptibility for lower extremity injuries. Although the course of our study, we found that PNF can be used during precompetition conditioning of the athletes, this infers that PNF plays a vital role in sporting events as it prevents from hamstring injuries such as hamstring strain and hamstring tear.


The present study demonstrated that 4 weeks of PNF training in amateur badminton players has favorable changes in their functional reach, flexibility, and range of motion of hamstring muscles. This study shall provide the efficacy of PNF stretching in improving flexibility and functional reach of lower extremity using YBT among amateur badminton players, which can be considered as a guideline for injury prediction and precompetition conditioning. Therefore, PNF technique is a reliable technique and decreases the injury probabilities such as hamstring strain and hamstring tear and increases range of motion.


In the 4 weeks' protocol, we did not isolate the subjects from their regular warm-up and cool-down period. The sample size was small. In our study, we only included effect of PNF on hamstring muscle and did not compare its result with other technique.

Future recommendations

The study can be done with large sample size and different age group. In the future, we can compare effect of PNF technique with other techniques on different muscle groups. In the future, we can also see the effect of height and weight on the range of motion because range of motion is directly proportional to height and inversely proportional to weight only under certain limits. The study can be done by increasing the duration of intervention and can also see its long-term effects on follow-up.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.


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