Hamstring Shortening, Short Hamstring Syndrome
Conditions
Keywords
hamstring shortening, short hamstring syndrome, athlete, physiotherapy, manual therapy, active release therapy, positional release therapy
Brief summary
Hamstring shortening is common in athletes and often causes pain, limited flexibility, and reduced function, which negatively impact performance. Manual therapy techniques such as Active Release Therapy (ART) and Positional Release Therapy (PRT) are frequently used, but their comparative effectiveness remains unclear. This randomized, single-blinded clinical trial enrolled 74 athletes aged 18-35 years with hamstring shortening at the University of Lahore. Participants were randomly assigned to receive either PRT with conventional physiotherapy (hot pack, TENS, stretching, ankle pumps) or ART with the same physiotherapy protocol. Each group received two supervised sessions per week for four weeks. The primary outcomes were pain (Numeric Pain Rating Scale), range of motion (Popliteal Angle), and functional ability (Lower Extremity Functional Scale). The Active Knee Extension test was used as a secondary outcome. This study seeks to determine which manual therapy approach provides greater improvements in pain, flexibility, and function, with the goal of guiding evidence-based rehabilitation for athletes.
Detailed description
Hamstring shortening, also referred to as short hamstring syndrome, is a frequent condition in athletes and has been linked to pain, reduced range of motion, and functional limitations that affect both sports performance and quality of life. Studies suggest that up to two-thirds of athletes may experience hamstring tightness, often as a result of repetitive strain, muscle imbalance, or inadequate recovery. Addressing this condition is therefore a priority in sports rehabilitation to minimize risk of injury and optimize performance. Manual therapy is widely used in clinical practice to manage hamstring-related impairments. Among the commonly applied methods, Active Release Therapy (ART) aims to release adhesions and improve soft tissue mobility through tension and guided movements, while Positional Release Therapy (PRT) works by placing the muscle in a position of comfort to promote relaxation and reduce neuromuscular tension. Although both techniques have shown promise individually, limited evidence exists directly comparing their effectiveness in athletes with hamstring shortening. This single-site, single-blinded randomized controlled trial was conducted at the University of Lahore Teaching Hospital to address this gap. Seventy-four athletes between 18 and 35 years of age were recruited using convenience sampling and randomized to one of two groups. Group A received Positional Release Therapy in addition to conventional physiotherapy, while Group B received Active Release Therapy with the same physiotherapy protocol. Conventional care included hot pack application, transcutaneous electrical nerve stimulation, hamstring stretching, and ankle pumps. Both groups received two sessions per week for four weeks, with outcome measures collected at baseline and post-intervention. The primary outcome measures were pain intensity, hamstring flexibility, and lower limb function, assessed respectively using the Numeric Pain Rating Scale (NPRS), Popliteal Angle test, and Lower Extremity Functional Scale (LEFS). The Active Knee Extension (AKE) test was included as a secondary outcome. The study design incorporated allocation concealment with sealed envelopes, blinding of assessors, and standardized protocols to minimize bias. By directly comparing PRT and ART, this trial aims to provide evidence to guide clinical decision-making for the management of hamstring shortening in athletes. The results may inform physiotherapists, sports medicine professionals, and rehabilitation specialists about the relative benefits of each technique and support the use of effective, evidence-based interventions to improve pain, flexibility, and function in athletic populations.
Interventions
BEHAVIORALPositional Release Therapy
A manual therapy technique applied to the medial and lateral hamstrings after conventional physiotherapy. In PRT, the affected muscle is placed in a position of maximal comfort and relative shortening, while gentle pressure and controlled joint movements are applied. This position is held for approximately 30 seconds and repeated three times per session. The method aims to decrease neuromuscular tension, reduce pain, and promote muscle relaxation through a reflexive response. Distinct from Active Release Therapy, PRT does not involve active contractions or longitudinal tension but instead relies on positioning and relaxation to achieve therapeutic effects.
BEHAVIORALActive Release Therapy
A manual therapy technique applied to the hamstrings after conventional physiotherapy. ART combines therapist-applied longitudinal tension with patient movement and brief isometric contractions of both hamstrings and quadriceps. The limb is guided through specific ranges of motion to break down adhesions, restore tissue mobility, and improve flexibility. Unlike Positional Release Therapy, ART is an active technique requiring patient engagement through contractions and controlled movement against resistance, targeting scar tissue and myofascial restrictions.
OTHERConventional Physiotherapy
Hot pack, TENS, hamstring stretching, ankle pumps (common to both groups).
Sponsors
University of Lahore
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
SINGLE (Outcomes Assessor)
Masking description
This was a single-blinded trial. The outcomes assessor was blinded to group allocation and not involved in treatment delivery. Randomization was performed using sealed opaque envelopes, and group assignments were concealed from the assessor throughout data collection to minimize bias.
Intervention model description
This study used a parallel assignment design in which 74 athletes with hamstring shortening were randomized into two equal groups. Group A received Positional Release Therapy combined with conventional physiotherapy, while Group B received Active Release Therapy combined with the same physiotherapy protocol.
Eligibility
Sex/Gender
ALL
Age
18 Years to 35 Years
Healthy volunteers
No
Inclusion criteria
* Participants with age between 18 to 35 * Both genders * Athletes with BMI between 18.5 kg/m² and 29.9 kg/m². * Basketball, Football And Badminton Players. * Athletes who practices atleast 3 days per week. * Participants with Numeric pain rating scale values \> 4. * Participants with unilateral tightness of hamstring muscle with SLR \< 80° and AKE \< 125°
Exclusion criteria
* Participants with any acute chronic hamstring strain or lower back pain. * Participants with leg length discrepancy. * Participants with a sedentary lifestyle. * Participants with upper motor neuron or lower motor neuron lesion. * Participants with any previous history of lower extremity injury in the past three months * Participants who are not willing to sign the consent
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Hamstring flexibility (Popliteal Angle test) | Baseline and 4 weeks after intervention | Hamstring flexibility was assessed with a universal goniometer during the Popliteal Angle test. Participants lay supine with the hip flexed to 90°, and the knee was extended until a stretch was felt. The angle between the thigh and lower leg was recorded; larger angles reflect greater hamstring tightness. This test is widely used to quantify hamstring shortening. |
| Pain intensity (Numeric Pain Rating Scale, NPRS) | Baseline and 4 weeks (end of intervention) | Pain severity in the posterior thigh was measured using the Numeric Pain Rating Scale (NPRS), an 11-point scale ranging from 0 (no pain) to 10 (worst imaginable pain). Participants reported their average pain over the preceding 24 hours. This outcome captures the degree of symptom relief experienced after either Positional Release Therapy or Active Release Therapy. |
| Lower extremity function (Lower Extremity Functional Scale, LEFS) | Baseline and 4 weeks after intervention | Functional ability was measured using the LEFS, a 20-item patient-reported questionnaire assessing difficulty with daily and sports-related lower limb activities. Each item is scored from 0 (extreme difficulty or unable to perform) to 4 (no difficulty), for a total score range of 0-80. Higher scores indicate better function. The LEFS has high reliability (0.85-0.99) and validity for musculoskeletal conditions. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Hamstring tightness (Active Knee Extension test, AKE) | Baseline and 4 weeks after intervention | Hamstring tightness was measured with the Active Knee Extension (AKE) test using a universal goniometer. Participants lay supine with the hip flexed to 90° and the knee initially flexed to 90°. They were instructed to actively extend the knee until a stretch or mild pain was felt, and the angle was recorded. An angle \>20° was classified as hamstring tightness. This test provides an active, participant-driven measure of flexibility, complementing the passive Popliteal Angle test. |
Countries
Pakistan
Outcome results
None listed