Ankle biomechanics demonstrates excessive and prolonged time to peak rearfoot eversion (see Foot Complex graph). We would not necessarily expect

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1 Case Study #1 The first case study is a runner presenting with bilateral shin splints with pain and tenderness along the medial aspect of the tibia. The symptoms have increased significantly over the last month as a result of increased mileage in preparation for an upcoming half marathon. For the past six months, there has been some pain and discomfort at the beginning of most runs, with a reduction in pain as the run progresses. There is pain following the run continuing until the next day. Over the past three months, the runner has switched to motion control shoes with gel inserts and has had direct treatment to the medial aspect of the tibia including ultrasound, intra- muscular stimulation and stretching to minimize the pain. All foot and arch anatomical alignment measures are within normal limits or slightly less than typically measured (see Alignment graph above). The runner exhibits a slight rearfoot varus standing posture and a low arch height index suggesting that we would expect to measure typical or reduced rearfoot eversion during gait. The slightly high but still within normal limits Q- angle may result in excessive hip and /or knee frontal plane mechanics if sufficient muscle strength is not present. Inspection of the Strength graph indicates that the runner may exhibit reduced frontal plane muscle stabilization in terms of weakness of the tibialis posterior and gluteus medius.

2 Ankle biomechanics demonstrates excessive and prolonged time to peak rearfoot eversion (see Foot Complex graph). We would not necessarily expect excessive rearfoot eversion considering the standing rearfoot varus posture and therefore assume that proximal factors such as excessive knee abduction will play a role. This hypothesis is reinforced considering that excessive tibial internal rotation is not measured. Tibial internal rotation and rearfoot eversion (pronation) are coupled motions. If excessive rearfoot eversion is not coupled with excessive tibial internal rotation, one must assume that the rearfoot is being induced into an excessive eversion position as a result of increased knee abduction and/ or hip adduction. The prolonged time to peak rearfoot eversion and high eversion velocity is the direct result of reduced tibialis posterior muscle strength and its inability to control rearfoot eversion during the first half of stance and bring the rearfoot into an inverted position during the last half of stance.

3 The hip and knee biomechanics graphs show excessive knee abduction, hip adduction and contralateral pelvic drop gait mechanics that are a direct result of reduced gluteus medius strength and the slightly high Q- angle. Since there is not an excessive amount of knee or hip rotation, the heel whip measure is within normal limits and sufficient range of motion is measured within the hip rotators, we can conclude that torsional forces are not playing a significant role in the medial tibial stress syndrome pain and symptoms. Inspection of the hip and knee biomechanics graphs show that we can visually observe an excessive knee abduction position with contralateral pelvic drop and an induced rearfoot eversion position at midstance.

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5 Treatment for this runner should include strengthening of the tibialis posterior and gluteus medius to resolve the excessive and prolonged time to peak rearfoot eversion and high rearfoot eversion velocity. Greater strength will also reduce the knee and hip rotation velocity. However, even if sufficient gluteus medius strength is achieved, one may continue to see slightly high amounts of knee abduction and hip adduction occurring considering the higher Q- angle measure. Also, one may still see a slightly high peak rearfoot eversion position as a result of the proximal influence in this mechanical pattern. Based on this information, a stability shoe would be the ideal shoe to minimize excessive peak rearfoot eversion and control excessive frontal plane forces from a distal aspect. Discontinuing the use of the motion control shoe and orthoses is necessary considering the typical foot anatomical alignment measures and the relatively rigid arch and standing rearfoot varus posture.