Journal of Integrated Health Sciences

ORIGINAL ARTICLE
Year
: 2018  |  Volume : 6  |  Issue : 2  |  Page : 64--68

A comparative study of muscle energy technique and positional release technique on hamstring flexibility in healthy individuals


Sejal Sailor, Yesha Mehta, Neha Shah, Anuja Trivedi 
 Department of Musculoskeletal Physiotherapy, SPB Physiotherapy College, Surat, Gujarat, India

Correspondence Address:
Sejal Sailor
Department of Musculoskeletal Physiotherapy, SPB Physiotherapy College, Ugat Bhesan Road, Surat - 395 005, Gujarat
India

Abstract

Background: Muscular flexibility is an essential aspect of normal human function. Flexibility can be gained by a variety of stretching techniques and other techniques, yet little work has been performed to compare these techniques. The objective of this study was to compare the effectiveness of muscle energy technique (MET) and positional release technique (PRT) on hamstring flexibility in healthy individual participants. Methods: Twenty-four healthy participants who met the inclusion criteria were randomly divided into two equal groups. Two groups following a home-based 2 weeks' (five 10 min sessions per week) hamstring stretching protocol (stretching performed by MET or by PRT). The range of motion (ROM) of knee extension was measured before and after stretching program by means of active knee extension test and active straight leg raise using universal goniometer. Results: There was a significant improvement in hamstring flexibility following the application of MET and PRT. However, increase in knee extension ROM was higher in MET compared to PRT. The change in the flexibility from the value at initial evaluation to after 2 weeks' intervention was also higher in the MET. Conclusion: The findings suggest that the MET is more effective than PRT for healthy individuals with normal and limited hamstring flexibility.



How to cite this article:
Sailor S, Mehta Y, Shah N, Trivedi A. A comparative study of muscle energy technique and positional release technique on hamstring flexibility in healthy individuals.J Integr Health Sci 2018;6:64-68


How to cite this URL:
Sailor S, Mehta Y, Shah N, Trivedi A. A comparative study of muscle energy technique and positional release technique on hamstring flexibility in healthy individuals. J Integr Health Sci [serial online] 2018 [cited 2019 Aug 19 ];6:64-68
Available from: http://www.jihs.in/text.asp?2018/6/2/64/252875


Full Text



 Introduction



Hamstring muscles are well known for their great tendency to shortening,[1],[2] which is due to their multi-joint function, their tonic postural character, and considerable amount of tensional forces to which they are constantly submitted.[3] The length of the hamstring muscles is considered to play an essential role in both the effectiveness and efficiency of fundamental human movements such as walking and running.[4] The literature shows that reduced hamstring flexibility is a common clinical finding in the general population[5] as well as athletic populations which result in major muscle imbalances, predisposing athletes to muscle injuries,[6] patellar tendinopathy, and patellofemoral pain[7],[8] as well as may lead to low back pain.

Considering the importance of hamstring flexibility in the general and athletic population, maintaining the flexibility of hamstring muscle is of utmost importance for health-care professionals and to achieve this goal one needs to know the most effective and efficient technique to obtain hamstring flexibility. Muscle stretching is commonly used in the general population as well as in sport and clinical contexts to maintain/restore good flexibility, improve muscle flexibility in case of tight muscles, or to treat or prevent musculoskeletal injuries (e.g., muscle strain).[9] Many stretching procedures are being used for hamstrings flexibility, including static stretching and dynamic stretching such as ballistic stretching and precontraction stretching, which is the technique of proprioceptive neuromuscular facilitation techniques.[10] Studies present different number of sets, duration of stretching, length of training, and ways to evaluate the flexibility. These inconsistencies diminish the efficacy of stretching and make it difficult to establish optimal static stretching training programs.[11]

Although most training parameters related to flexibility programs for the hamstrings have been investigated, no study has yet been conducted to specifically compare hamstrings stretches which differ depending on the joint at which the stretching is focused. Yet, as previously mentioned, these stretches might have a different influence on the muscle and nervous system structures, and consequently, on the range of motion (ROM) improvement.

Therefore, the aim of the present study was to compare the effectiveness of muscle energy technique (MET) and positional release technique (PRT) on hamstring tightness among normal healthy individuals.

 Methods



The study was a randomized clinical trial conducted in the Department of Musculoskeletal Physiotherapy of the Institute. Participants were randomly assigned following simple randomization procedure into two groups with different stretching protocol as follows: METs and PRT. Preparticipation and postintervention assessment were conducted by one therapist, randomization by the second therapist, and protocol for MET and PRT was performed by physiotherapists specialized in orthopedic manual therapy.

Participants

Twenty-four male or female students of the institute were voluntarily participated in this study. Inclusion criteria for the study were willingness to participate, aged between 18 and 25 years, marked loss of active and passive ROM of hip and knee joint, hamstring trigger point and tightness defined by minimum 30° restriction in straight leg raise (SLR) unilaterally or bilaterally, and a positive active knee extension (AKE) test. Participants with any medical history of injury to back, inflammatory conditions, having history of undergone surgery in the last 3 months, with hamstring injuries and strains, knee deformities and injuries, fractures that may have affected the lower extremity within the past 6 months, any neurological condition (any cerebrovascular accident), peripheral vascular disease, and those who unwilling to participate were excluded from the study. [Figure 1] presents the enrollment and allocation of participants in groups. All participants were informed about the objective of the study before participation and were free to withdraw at any time from the study. The written informed consent was also obtained from all the participants.{Figure 1}

Procedures

Design of the study

This study was a pretest–posttest comparative experimental design. Participants who met the inclusion criteria were selected for the study. After that, the participants were assessed for baseline data by measuring the AKE test and active SLR tests using universal goniometer. Participants were randomly assigned into MET group (n = 12) or PRT group (n = 12). The interventions were given for 5 days per week for 2 weeks. All the participants were assessed (same as baseline measurement) after 2-week intervention. All measurements were taken three times, and average values of three trials were taken.

Stretching protocols

Muscle energy technique protocol

The supine patient fully flexes the hip on the affected side. The flexed knee is extended by the practitioner to the point of resistance (identifying the barrier). The calf of the treated leg is placed on the shoulder of the therapist, who stands facing the head of the table on the side of the treated leg. If the right leg of the patient is being treated, the calf will rest on the practitioner's right shoulder, and the practitioner's right hand stabilizes the patient's extended unaffected leg against the table. The practitioner's left hand holds the treated leg thigh to both maintain stability and to palpate for bind when the barrier is being assessed. The patient is asked to attempt to straighten the lower leg (i.e., extend the knee) utilizing the antagonists to the hamstrings, employing 20% of the strength in the quadriceps. This is resisted by the practitioner for 7–10 s. Appropriate breathing instructions should be given. The leg is then extended at the knee to its new hamstring limit if the problem is acute (or stretched slightly if chronic) after relaxation and the procedure is then repeated.[12]

Positional release technique protocol

Medial hamstring – This tender point is located on the posterior, medial surface of the tibia, on the tendinous attachments of the semimembranosus and the semitendinosus. Pressure is applied anteriorly. The patient lies supine with the affected thigh extended and abducted off the edge of the table. The therapist then flexes the affected knee 40° and adds slight adduction (varus force) and marked internal rotation of the tibia.[13]

Lateral hamstring – This tender point is located on the posterior, lateral surface of the head of the fibula, on the tendinous attachment of the biceps femoris. Pressure is applied anteromedially. Position of treatment – The patient lies in supine with the affected thigh extended and abducted off the edge of the table. The therapist flexes the affected knee approximately 40° and then either abducts or adducts the lower leg (usually slight abduction, i.e., valgus force to the tibia). The tibia is then either internally or externally rotated (usually external rotation).

Outcome measurement

Active knee extension hamstring flexibility test

Participants were assessed on a plinth in the supine position with both lower extremities extended. Both anterior superior iliac spines were positioned properly. The lower extremity not being measured was secured to the plinth using a strap across the lower third of the thigh. Each assessor marked the lateral knee joint line with washable ink. From there, two lines were drawn. The first was drawn to the greater trochanter and another to other was drawn to the apex of the lateral malleolus. The participants were told to flex the hip until 90°. The participants were asked to extend the leg as much as possible while keeping their foot relaxed and to hold the position for about 5 s. A standard universal goniometer was placed over the marked joint axis, and the goniometer arms were aligned along the femur and fibula. The AKE measurement was defined as the degree of knee flexion from terminal knee extension. Each knee was measured thrice, and the mean angle of the AKE test was used for the analysis.[14]

Active straight leg raise test

In the active SLR test, the participants were asked to lift the leg as high as possible three times at 10 s intervals while keeping the knee in extension. Repetitions were performed to improve the contraction force, which increases the active ROM. The average of three results was recorded for the analysis.

Statistical analysis

The minimum sample size was estimated using two-sample two-sided equality-based sample size calculations. The minimum required number of sample size was estimated at 12 participants per group to detect the difference between groups on the retest when α was <0.05 and power was 80% with an effect size of 0.3.[15]

Statistical analysis was conducted using the SPSS (Software Version 20.0, IBM, USA). The Kolmogorov–Smirnov test was used to determine the normal distribution of the data. The descriptive analysis was performed for the demographic data and represented as mean and standard deviation. Unpaired t-test was applied to examine the difference between the two groups. To compare the mean values of ROM between two groups, two-way repeated measures ANOVA using two factors (test time: before and after 2 weeks, and groups: MET group and PRT group) was used to analyze interaction effects. When a significant interaction was observed, a paired t-test was used for comparing the pre- and post-treatment values in each group. The alpha level of 0.05 with 95% confidence interval was used to denote statistical significance difference.

 Results



Twenty-four students were selected from 38 participants (mean age: 20.4 ± 1.3 years old; mean AKE left: 32.5° ± 6.4°, mean AKE right: 27.8° ± 3.2°; mean SLR angle right: 56.8° ± 8.8°, mean SLR angle left: 56.3° ± 9.3°; and females: n = 21, males: n = 03) based on the inclusion/exclusion criteria which play an important role in removing the influence of specific confounding variables.

Twenty-four participants were randomly assigned into MET (n = 12) and PRT (n = 12) groups. Their demographic parameters [Table 1] and baseline characteristics did not differ from the ones of the other participants in both groups. While data obtained after 2 weeks' stretching program shows a significant difference (P < 0.05) between groups except SLR values for right side [Table 2].{Table 1}{Table 2}

[Table 2] shows the results of the tests of within-subjects effects and paired sample t-test. The repeated-measure ANOVA analyses indicated significant group-by-time interactions for all outcomes, indicating that ROM improved differently between groups (greater increase in MET groups than in the PRT). In addition, the time effect was also highly significant for all outcomes.

In MET and PRT group, ROM in AKE and SLR significantly increased after posttest. However, the improvement in MET was better than that of PRT evident from higher mean difference between pre- and post-treatment data [Table 2]. According to the comparison of mean difference values of pre- and post-test between MET and PRT, the difference was significantly higher in MET compared to PRT.

 Discussion



This study was undertaken to investigate the influence of MET and PRT for hamstring flexibility. The results of this study demonstrate that both MET and PRT were effective at improving AKE and SLR angles following 2 weeks' stretching program which was concurred with existing studies that had reported that the stretching training program increased the flexibility of hamstring.[16]

Increase in ROM following a stretching training program has been explain through various hypothesis proposed by the different study. Adel Rashad Ahmed in their study found significant improvement in hamstring flexibility in both the techniques, the MET and dynamic stretching yet the improvement in MET was better than that of dynamic stretching.[17] Selkow et al. also described the effectiveness of MET for hamstring muscle.[18] In addition, some studies reported the analgesic effect of MET.[19],[20],[21] On the other hand, Ballantyne et al. argued and hesitate about the efficacy of MET in the form of postisometric relaxation (PIR).[22] They suggested that the PIR theory and its consequent hypoanalgesic effects are poorly supported by research. Allen also studied the effectiveness of MET in improving hamstring flexibility and considered MET a statistically significant intervention in improving hamstring flexibility in patients with hamstring injuries.[23] Therefore, stretching training programs can be recommended for clinical practice in which hamstring flexibility is required.

The present study showed that the improvement in hamstring flexibility in the PRT group was less than that of MET group. The reason for this difference may be due to the increase in muscle length by a combined effect of creep and plastic change in the connective tissue.[24] It was also concluded that 30 s as the optimal duration for an efficient stretch in MET protocol which can maintain muscle elongation for the same duration leads to increase in muscle length.[25]

There has been limited research on the effects of positional release therapy on hamstring flexibility. PRT is proposed to affect both the medial and lateral hamstrings (i.e., both are put into a shortened position). However, the technique used in the present study required that internal rotation of the tibia should be added to achieve the optimal treatment position for the medial hamstrings, whereas either internal or external rotation of tibia may be optimal for the lateral hamstrings. Therefore, it is possible that the technique used was less effective for participants who might have had decreased flexibility confined to the lateral hamstrings and required the addition of external rather than internal rotation of the tibia to achieve the optimal treatment position. Trevor B Birmingham found that positional release therapy and sham technique result in similar level of flexibility.[26] He indicates that the PRT technique is not effective to improve knee extension because of hamstring tightness. This supports our study which suggests that PRT is not much effective than MET in improving hamstring flexibility. Kaandeepan et al.[27] in his study found that both the techniques, static stretching and PRT, equally effective while D'Ambrogio and Roth described that the PRT may be effective in producing reduction of joint hypomobility in case of musculoskeletal dysfunction.[28] Thus, the PRT technique should be recommended for use when the study involves hamstring flexibility on older participants as it is very easier to apply and less painful compared to other stretching.

The results of the present study corroborate the previous findings about a significant correlation between AKE and active SLR results for hamstring flexibility.[29] As both the AKE and the active SLR tests assess primarily, the hamstrings extensibility with different forms like AKE measures the angle of knee extension, while active SLR measures the angle of the straight leg to the horizontal.

This study also has some limitations that need to be addressed. First, the sample size was small; second, there was no control group to study the change in hamstring flexibility without stretching program; third, the participants were healthy young individuals; it is unknown whether the stretching protocol used in this study could be effective for the elderly or participants with a history of hamstring muscle strains; fourth, no follow-up is took place in the present study; and finally, the effect was focused only on immediate effect. Further studies are still needed to find the comparison of sustained effect or effects after the long-term intervention of both MET and PRT techniques on hamstrings flexibility and effects of both techniques in different types of population.

 Conclusion



On the basis of the present study result, it is concluded that both MET and PRT techniques are effective in improving hamstring flexibility in healthy young adults with normal and limited hamstring flexibility. However, the percentage change in ROM after 2 weeks' intervention was higher in MET than PRT technique.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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