Hip Angle

Hip angle is a general term given describe a critical aspect of bike fit. Hip angle can be measured, although I've yet to see a perfect method of doing so. I measure hip angle as the angle between the flat section of the lower back and the femur. Your hip angle varies throughout the pedal stroke, when your foot is at top dead center (tdc), your hip angle is at its smallest. When your leg is fully extended at bottom dead center (bdc), your hip angle is at it's most obtuse. When considering hip angle, the critical point is at the top of the pedal stroke, this is called the minumum hip angle.

A riders hip angle has a direct influence on the recruitment of the hip flexors and the glutues muscles. Muscles act a lot like rubber bands, they are extended by an outside force and they generate force in tension. Your hip flexors are on the front of your thigh, right around the waist line. They connect to the front of the thigh and to the lower torso. The hip flexors work to lift your leg and to bring your thigh forward. I hope you know where your glutes are, they work to lower your thigh, as during the downward stroke.

As a rider takes on a more acute minimum hip angle, the glute muscles are further lengthened at the top of the pedal stroke and therefore able to do more work during the downward stroke. The trade off here is that in the process of lengthening your glutes, your hip flexors have become short and now they are at a disadvantage from a work standpoint. The hip flexors might not be able to fire at all, giving you a choppy pedal stroke.

Finding the minimum hip angle that gives the right balance of power from the glutes and the hip flexors is a key parameter in a good bike fit. Fortunately for road bikers, the road handlebar has a variety of hand positions which allows the rider to vary their minimum hip angle. On time trial and triathlon bikes, there is only one position a rider should be riding in, so getting the hip angle right here is critical.

How do you know if your minimum hip angle is too acute? There are a few things to consider:

-If you have a hard time digesting foods or liquids on the bike, your hip angle could be too acute and you might physically be squishing your stomach when your foot is at TDC.

-If you experience cramping or spasms of your hip flexors.

-If you experience low or mid back pain when on the bike (although lots of factors can contribute to this)

-If you can't climb any hills in your drops (road bike) or you can't stay in your aero bars (TT or Triathlon bike)

-If your thighs splay outward at the top of the pedal stroke (this can be helped by loosening up your glutes through DYNAMIC stretch or massage techniques).