In Part 1 we looked at the function and physiology of tight muscles and how progressive lengthening and strengthening can improve your rehabilitation and performance. Part two of this series looks at the bio-mechanical implications of tight hamstrings.
The mighty Hip Hinge
This action is arguably the most important movement for a healthy low back but also for force production through your hips. To simplify: hinging at the hip is what should happen when you bend forward at the waist. In an ideal movement your torso maintains a neutral (picture 2) posture while almost all of the forward bend occurs around your hip axes. A poorly performed forward bent shows limited change in the hip angle with excessive bending through the low back.
Poor movement or posture in this forward bend excessively loads your spine and intervertebral discs. It also destroys any mechanical advantage meaning our muscles have to fire harder when we bend forward and return to standing. Think through how many times in the run of a day would you bend forward and return to standing. Imagine you work in a plant or factory where you spend the majority of your day leaning forward over an assembly line or work table. How long before this excessive loading starts to wear on the joints and tissues of your back.
Back to hamstrings. They are one of the strongest limiters for this hip hinge. In a proper hip hinge you take your hamstrings through considerable lengthening. If you lack flexbility in your hamstrings you will quick stop pivoting about your hips because your hamstrings have pulled tight. If your haven’t reached the end of your required movement then you will likely bend through your spine to make up the difference.