Last time we identified the importance of hip internal rotation (IR), particularly for movements requiring deep hip flexion or whole body rotation. So how do we go about determining whether or not a lack of IR could be limiting either your performances or those of your athletes?
How to Assess Internal Rotation
Here’s one for you. When is an external rotator not an external rotator? When it’s an internal rotator! As the hip becomes flexed it causes a natural pull into IR and this changes the main action of many of the individual hip muscles (Table 1). For this reason it is important to assess IR with the hip in both flexion and extension; it can help determine where the limitation lies.
It is also important that we assess range of motion (ROM) both actively and passively. This means testing ROM with the athlete performing the movement themselves (active) and then performing the movement with assistance (passive). If passive ROM is greater than active ROM then it’s a good indicator that weakness in the IR’s is driving the problem. Conversely, if there’s no improvement in passive ROM, then it’s likely that tightness is the key issue.
This is the most widely used screening for IR; here we’re assessing it with the hip in flexion. For this assessment the athlete is seated on a table, or high bench, with their legs dangling above the floor and the knee bent to 90o. Whilst keeping the knee stationary the athlete attempts to abduct the foot, moving it as far away from the body as possible. If using a goniometer, the fulcrum should be on the patella, the stationary arm perpendicular to the floor and the movement arm along the midline of the tibia.
This time we’re assessing IR with hip in extension. The athlete lies face down and flexes their knee to 90o. From here it’s the same deal again, the athlete keeps the knee stationary and attempts to adduct the foot. Be aware that many athletes don’t naturally get into a position with the hips extended so don’t take the start position as a given. Goniometer set-up is as above but do expect ROM, particularly active ROM, to be slightly improved from the seated 90/90 as gravity provides a little bit of assistance.
Supine Straight Leg
Personally I find that this one is a bit less sensitive to changes in ROM but I’m sure that in the right hands this isn’t an issue. This is probably the best assessment for rotational athletes from a functional standpoint as the both hip and knee are extended. For this one the athlete begins lying flat on their back. Imagine the foot resembles a clock face; keep the heel as the fixed, central point and then get them to move their toes either clockwise (for the left foot) or anti-clockwise (for the right foot). I’m not sure about the textbook goniometer set up for this but I go with the fulcrum at the base of the heel, stationary arm perpendicular to the floor and the movement arm along the line of the second toe.
Remember, you’re looking for about 35o for general athletes and 45o for those with deep hip flexion or rotational needs. Very, very few people actually come anywhere near to this!
Right, now you know why we need it and now you know how to assess it. Tomorrow we go through the action plan for dealing with a deficit in hip IR!