Influence of Posture 101
Wednesday, August 21, 2013 at 09:25PM
Aaron in anterior pelvic tilt, assessment, corrective exercise, hamstrings flexibility, lumbar spine, mobility, posture

Read time: 5-7 min

“Tight” hamstrings afflict many people and can have significant effects on how they perform a number of movements. Today’s post will demonstrate why stretching the hamstrings may not be the solution if you experience tight hamstrings. We’ll focus on the influence of posture and position on the state of our muscles.

Mobility limitations often present themselves as a sensation of “tightness” in certain areas of the body when performing certain exercises. The go-to approach for many is to stretch the area that feels tight. However, this approach does not address other factors that may contribute to tight muscles. As a result, after weeks, months, or even years of stretching, many individuals experience little, if any, relief from their tight muscles.

Factors such as posture or position of the body, tissue (muscle and/or connective tissue) quality, and motor control can influence our perception of how our muscles feel on a tight/loose spectrum. Other things like stress and fatigue can also play a big role in how we perceive our muscles to feel on that spectrum.

Aside from annoyance and discomfort in our daily lives, tight hamstrings can translate in the gym into the all-too-common butt-tuck during squat movements. During hip hinge patterns, like the RDL or kettlebell swing, tight hamstrings can limit range of motion or cause the lower back to round.

These compensations limit the effectiveness of a given exercise, thereby limiting performance. They also increase stress on the low back and increase the potential for injury. Improper stretching of a muscle that is already of sufficient length can lead to (sometimes permanent) changes that reduce force production and increase the likelihood of a tear.

Figure 1. Excessive lumbar extension and anterior pelvic tilt.

Figure 1 shows a posture of excessive lumbar extension (arching the low back) and anterior pelvic tilt, which is a common posture when standing. It is also a common (though ineffective) setup when performing any squat variation.

This posture stretches the hamstrings! When you stretch a muscle, you increase its tension (i.e. it feels tighter than when it is not being stretched!). Many people experiencing tight hamstrings are stuck in this posture without realizing it. These individuals’ hamstrings are already stretched beyond normal, resting length in their everyday posture. It should come as no surprise that stretching protocols provide little relief for these individuals.

It is crucial to be able to differentiate the possible causes of any mobility limitation or movement dysfunction. A proper, thorough assessment will provide valuable information necessary for choosing appropriate corrective strategies needed to target specific issues.

Figure 2. Demonstration of the passive straight-leg raise to assess hamstrings length.

For hamstrings tightness, the passive straight-leg raise (Figure 2) helps us assess whether hamstrings length is an issue. The test demonstrated in Figure 2 confirms that this individual has normal hamstrings length. Thus, any perceived “tightness” is not due to the muscle being too short, so stretching would not be an effective mean to alleviate the tightness!

Figure 3. Comparison of hip flexion with two different postures.

In Figure 3, notice the effects of posture and position on hip flexion, which is involved in many exercises. Figure 3A simulates the bottom position of a squat with excessive lumbar extension and anterior pelvic tilt. Figure 3B replicates the bottom position of a squat with neutral spine and pelvic position. Observe where the knee is in relation to the hip crease at the end range of hip flexion during each position.

At Five Rings Athletics, tests like these are just part of our diagnostic assessment. In conjunction with joint range of motion tests, we utilize specific dynamic and isolated movement tests to assess local and global movement capacity and limitations. We strive to identify the influence of posture/position, physiologic factors, musculoskeletal factors, and motor control on how someone moves and how they should be able to move.

Our diagnostic assessment gives us the information we need to create performance-oriented programs that simultaneously work within an individual’s current movement capacity and make strides toward improving that capacity. If you’re interested in unlocking your movement and taking your performance to the next level, check out our Services and see which option best fits your needs.

Article originally appeared on Five Rings Athletics - Excellence through Sport (
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