The hamstring (muscles of the posterior compartment of the thigh) is one of the most common muscles in our body that tends to get tight and even undergo shortening. This affects the normal biomechanics and can cause musculoskeletal problems. The hamstring muscle is a multi-joint muscle that is most frequently injured in the human body. Prolonged sitting is a contributing factor to decreased hamstring flexibility. The ability of muscles to lengthen is called flexibility, which allows one or more joints in a series to move through the range of motion.
The sedentary lifestyle is a most common reason for postural abnormalities evident in modern society. The prolonged sitting hours can affect soft tissues flexibility, especially two joint muscles. Prolonged sitting can cause tightness of the hamstrings in young students who have to sit for long hours of teaching [1]. Tightness of posterior thigh muscles results in decreased ability to extend the knee completely with hip flexion accompanied by pain along the posterior side of thigh or knee. Hamstring tightness may be found in both symptomatic and asymptomatic subjects. Hamstring tightness is a most obvious cause of back pain and it may lead to the patellofemoral syndrome. The tight hamstring is also a risk factor for the development of patellar tendinopathy and patellofemoral pain.
Tight hamstrings can limit anterior pelvic tilt during forward trunk bending, and this limitation can result in increased tension in muscular and ligamentous structures in the lower back. Tight hamstrings are also responsible for severe restriction in straight leg raising. Tightness cause changes in the length-tension relationship of muscle and also affects the shock- absorbing capacity of a limb. Thus, it can cause a vicious cycle of restriction in range of motion during functional activities and aggravates abnormal posture. Mobility of soft tissues and joints is very important in maintaining static and dynamic postures and in preventing injury and re- injury of soft tissues.
The favorite recreational physical activities cherished by humans are walking and running. They play an important role in improving physical and mental health. Retrowalking or backward moving is a new concept in the field of physical therapy and rehabilitation to improve the flexibility of hamstring muscles. Retro walking is a backward method of locomotion. Backward walking is a mirror picture of forward walking i-e the joint patterns are similar to FW but with a simple temporal reversal. However, the biomechanics of BW as compared to FW differs greatly. Forward walking initiates with heel contact and ends with toe-off while in backward walking toes contact the ground first and the heel is lifted off the ground at the end of the stance. Backward walking is associated with increased cadence and decreased stride length as compared to forward walking.
Retrowalking is beneficial as compared to forward walking alone because it produces more muscle activation in proportion to effort than forward walking. It improves oxygen uptake, cardiopulmonary fitness, and muscle activity while simultaneously decreasing joint stress. Retro walking is also used in specific sports to practice and train athletic skills and to reduce the potential for injury, such as, in basketball, American football and soccer players incorporate backward running during competition to improve performance and to decrease the risk of injury. Stretching exercises are used to improve the flexibility of muscles. An increase in muscle flexibility as a result of stretching exercises may reduce the risk of musculoskeletal injuries, decrease and relieve muscle soreness, and increase muscle performance. Three types of stretching exercises are used to enhance muscle flexibility: static stretching, ballistic stretching, and PNF techniques [2].
A slump test is an assessment tool used to detect altered neuro-dynamics or neural tissue sensitivity. During the slump test, the neural structures within the vertebral canal and foramen are slowly and progressively put on maximum stretch. Slump stretch is also a neuro-dynamic treatment. According to recent research, it can be used as an intervention in patients with hamstring tightness. It is also found to be effective in low back pain as hamstring tightness may cause low back pain thus slump stretch can be effective in patients having low back pain. This stretch can be used to unwind the sciatic nerve from fascia and muscle tissue. Thus, effective in sciatic pain and piriformis syndrome. Neurodynamics increases the activity of muscles more significantly than that observed at rest [3,4]. When applying neurodynamics, tension occurs in the nervous system, and pressure within the nerve increases due to the decrease of the cross- sectional area, and the axonal transport system lengthens the sciatic nerve after shortening because of the influence of the surrounding related structures and hamstring flexibility.
STUDY GAP
Several pieces of research have been conducted on slump stretch and retro walking that show positive effects of both interventions but there is a lack of clinical research to compare the effects of slump stretch and retro walking on hamstring flexibility. But until now there is no comparative study in the literature to compare the effects of retro walking and slump stretch on hamstring flexibility.
RATIONALE
This study is conducted to find which technique (slump stretch and retro walking) is most significant for the flexibility of hamstrings, so it can be used to improve the flexibility among the female population.
Material & Methods
- Study Design
Pre-test Post-test study design (Quasi experimental study)
Study Settings: Gujranwala Institute of Rehabilitation Sciences
Study Duration: 6 weeks (5 days / week)
Participant Selection
- Sampling Technique
Convenient sampling technique
- Inclusion criteria
- Females only
- Age between 18-30 years
- Active Knee Extension < 160 degree
- Exclusion criteria
- Individuals with a hamstring injury in the past year
- Any past traumatic or surgical history of lower extremity
- Subject with a history of arthroplasty
- Individuals with musculoskeletal problems
- Individuals with underlying systemic pathology
- Pregnancy
- A patient who had a severe spinal deformity, spondylosis, spondylolisthesis, lumbar canal stenosis, and disc herniation
1- Sample Size
The calculated sample size using ROM as an outcome measure is 30 in each group after adding 20% dropout the sample size will be 30+6=36 in each group [4].
Z1-α/2 Level of significance=95%
µ1 Expected mean change in ROM in Group A= 141.20 µ2 Expected mean change in ROM in Group B= 7.8740
δ1 Expected standard deviation in group A=135.96 δ2 Expected standard deviation in group B=6.4451 Z1-β power of the study= 80%
n Expected sample size in a group= 30
After adding 20% drop out 30+6=36 in each group
Data Collection Procedure
Prior to the procedure, the following two tests were performed:
- AKE Test
ROM of both sides was checked by using a goniometer. The subject is in a supine lying position and his hip (of testing side) is 90-degree flexed while the other side (non- testing hip) is in a neutral position. Then the subject actively extended the respective knee as far as possible. The lateral epicondyle of the femur and lateral malleolus of the ankle were used as landmarks for the measurement [5].
Reliability of AKE test is 0.87 to 0.94.
Sit & Reach Test
The participant was sitting with her feet approximately hip-wide against the testing box. She kept her knees extended and placed the right hand over the left, and slowly reached forward as far as she could by sliding her hands along the measuring board.
Following baseline measurements, the subjects (n=60) were randomized into one of the 2 groups: Group A (N=30): retrowalking and Group B (N=30): Slump stretch.
Consort Diagram
Both groups followed protocol 5 days / week for 6 weeks and subjects in both the groups were instructed that no other exercise is to be followed at home.
Group A
The participants in group A completed 15 min of retro walking training with a 5-min forward walking warm-up session, at their comfortable walking speed [6].
Group B
Group B performed slump stretch actively by sitting erect with the right foot supported on the floor ang pointing straight ahead (no hip internal or external rotation). The right leg is supported on the elevated surface (high enough to cause a significant stretch in the posterior compartment of the thigh) in front of the participant with the knee fully extended and toes pointed towards the ceiling (with no hip internal or external rotation). The participant then flexed forward from the hip, maintaining the spine in a neutral position, while reaching the arms and fingers towards the toes until a significant stretch was felt in the posterior compartment of the thigh. Once this position was achieved, the stretch was sustained for 30 seconds. Then the same procedure is applied to the contralateral limb.
