Kettle Bell Windmills
By Brent Brookbush MS, PES, CES, CSCS, ACSM H/FS
This exercise requires more than optimal flexibility from several joint structures – lumbar spine, hip, and potentially the shoulder. The spine (lumbar and thoracic) allows roughly 18° - 38° of lateral flexion, and the hip only allows an additional 20° - 30°. At most the capacity of the human body to side bend with the back leg fixed is 68°. This is far from the 90° + that would be required to side bend and touch one’s toe with a kettle bell. This forces compensatory movement patterns at both the spine and the hip.
The spine is forced to maximally laterally flex with the addition of rotation and flexion while under considerable load. This is a potentially dangerous position that taxes all supporting musculature at end range, and as explained in the intro likely passes much of the force to passive tissues supporting the spine (posterior longitudinal ligament, ligamentum flavum, interspinous ligament, supraspinous ligament, intervertebral disks, and facet joint capsules respectively).
Further this may reinforce compensatory patterns synonymous with an anterior pelvic tilt by increasing strength of the quadratus lumborum, erector spinae, and latissimus dorsi.
The hip (outside hip, opposite to the foot that is reached for) is forced to adduct maximally before adopting compensatory rotation and flexion, with considerable strain to the sacroiliac joint. In order to assume a maximally adducted position most individuals will “sit back into their hip”. This is synonymous with a Positive Trendelenburg’s Sign (inhibition or weakness of the gluteus medius – “hip drop”), and inhibition of the gluteus maximus. This at minimum increases force on the superior labrum of the hip, and the superior and posterior joint capsule.
Far more disturbing is the reliance on the deep longitudinal sub-system (sacrotuberous ligament, biceps femoris, peroneals). Reliance on this subsystem as a prime-mover, specifically the biceps femoris as a hip extensor reinforces common compensation patterns, and is potentially hazardous to sacroiliac joint mechanics. When the biceps femoris is forced to act as a prime mover during eccentric control of hip flexion it increases tension on the sacrotuberous ligament and causes the sacrum to posterior tilt relative to the illium. If continued, this could lead to dyskinesis of the SI joint, leading to arthrokinetic inhibition of the glute complex, increased reliance on the deep longitudinal sub-system during extension mechanics – reinforcing a pattern that increases the likely-hood of low-back and SI joint pain.
The shoulder may also be compromised (the arm overhead). If an individual does rotate and flex at the spine, the shoulder must horizontally abduct beyond optimal range to keep the weight perpendicular to the floor and maintain force through the center of the arm. Generally this leads to anterior tipping - inhibiting scapular stabilizers (traps and serratus anterior), and the position of the humerus relative to the scapula compromises shoulder joint stability and increases strain on rotator cuff musculature.
My last point is once again, why? What functional movement pattern, or sport related activity does this exercise prepare you for? I understand it’s hard, but hard does not necessarily equate to an increase in performance. The risks associated with an exercise that seems to have little, if any, benefit to common training goals places this exercise at the top of my questionable exercise list.
© 2011 Brent Brookbush
Questions, comments, and criticisms are welcomed and encouraged –