The anawer to your question depends on how the hamstrings length are being measured. I am assuming you are using popliteal angles to do this?? If so, and if you are measuring the popliteal angles with the contralateral leg extended the pelvis will be anteriorly tilted, stretching the hamstrings resulting in a large measurement ie apparent hamstring tightness. Alternatively if you can have someone else helping you to flex the contralateral hip and knee up to a point where the pelvis is neutral ie ASIS and PSIS aligned vertically the popliteal angle measured should be less ie hamsteings less tight. Usually the difference between both measurements is 10 degrees if this is more then it is likely that the cause for higher popliteal angles is the pelvic tilt stretching the hamstrings thus limiting knee extension I hope I understood the question and this helps

Thank you so much sir,yes ,i am using the popliteal angle as the measurement,just i will try this way out and surely come back with the results.

With hyperextension of the trunk or an anterior pelvic tilt, hamstrings will appear short with testing. What we usually see though is tight hamstrings and the pelvis adoping a more posterior tilted position as a compensation, especially when the subject is asked to perform a hamstring stretch. Best to monitor pelvis with stretching of the hamstrings to insure accuracy. Another compensation seen in standing with tight hamstrings is knee flexion in addition to either an anterior or posterior tilted pelvis.

In the theoretical lower crossed syndrome you are describing the gluteal muscles are week, and they are prime hip extensors. The hamstrings are primary knee flexors, and secondary hip extensors. Hamstrings are often short simply because we sit too much.

On a neurological level as with Cerebral Palsy for example as well as with the orthopaedic population you will get compensatory postural hamstring tightness to increase stability.

The long head of the biceps femoris, as part of the hamstrings, attaches to the sacrotuberous ligament. When control of the SI joint diminishes, the most likely joint position is counter nutation (=anterior pelvic tilt). In this position the body attempts to increase joint compression in order to achieve stability. This can be done by increasing hamstring tension. Therefore anterior pevic tilt is often combined with increased hamstring tension.

Article A functional-anatomical approach to the spine-pelvis mechani...

A different kind of explanation,the article you had recommended is quite interesting,well this clears up my doubt,thank you

Welcome...

That's exactly the reason why positioning the pelvis neutrally when measuring popliteal angles gives a better indication of hamstrings length.

Sorry Jose,

Measuring hamstring length in the living is useless. Hamstring 'length' is mainly determined by tension, not actual length. Since it is tension (neurological driven) theoretically it can change within seconds. So why measure? Also hamstring stretching with the aim of lengthening is not very usefull. When hamstrings are 'short' they usiually are compensating some other problem (pelvis or knee joint). So it is better to look for (and solve) the underlying cause instead of stretching the hams.

Hello Jan-Paul,

Whilst I understand the reasoning behind your argument, it does not apply to all patient populations. In our gait analysis laboratory we see patients with cerebral palsy, some of them walk in crouch and are referred to us for consideration of surgical hamstring lengthening. We measure popliteal angles in two positions, with the contralateral hip extended and flexed (neutral pelvic position) in order to estimate hamstring lengths. We also assess muscle strength and muscle tone, and although every measurement, (particularly tone) has limitations and is prone to error, both from the measurement device and patient variability, when added to the 3D gait analysis outcomes they help towards the decision making process and they are particularly useful when comparing before and after surgery/treatment. The following article exemplifies the importance of these measurements.

http://www.ncbi.nlm.nih.gov/pubmed/19034182

Dear Jose,

Indeed there are exceptions. If for some reason a joint is kept in a flexed position over a longer period, the muscular structure will adopt. In these cases there is a change in actual length. But this primarily happens in situations that lead to these prolongued states as a cerebral palsy. On the other hand however, many patients with cerebral palsy tend to hypertone muscles. When they try to achieve something their muscle tone increases, leading to apparent short muscles. Sometimes this can be influenced by trying actions 'without effort', from a relaxed state (of mind). This can be compared with the chinese T'ai chi exercise. So yes, sometimes muscles can be short, but don't take it for granted untill you are sure. Maybe your equipment can measure that.

We used to add kinematic and kinetic data for decission making. If you are familiar with Dynamic Muscle Length graphs psoas or rectors femoris spasticity or contracture could be in relation with "false hamstrings thigthness". Try with Modified Popliteal Angle test. (Keenan,WN et al. J Ped Othop, 2004).

In other populations neural tissue tension mut be taken in consideration (SLR test).