The relationship of body weight and clinical foot and ankle measurements to the heel forces of forward and backward walking.

OBJECTIVE

To compare and contrast the relationships of selected static clinical measurements with the heel forces of forward and backward walking among healthy high school athletes.

DESIGN AND SETTING

Single-group, cross-order-controlled, repeated-measures design. All data were collected in a high school athletic training room.

SUBJECTS

Seventeen healthy high school student-athlete volunteers.

MEASUREMENTS

We performed static clinical measurements of the foot, ankle, and knee using handheld goniometers. We used a metric ruler to assess navicular drop and a beam balance platform scale to measure body weight. Mean peak heel forces were measured using F-scan insole force sensors. Data were sampled for 3 5-second trials (50-Hz sampling rate). Mean peak heel forces were determined from 3 to 5 consecutive right foot contacts during forward and backward walking at approximately 4.02 to 4.83 km/h (2.5 to 3.0 mph). Subjects wore their own athletic shoes and alternated their initial walking direction.

RESULTS

Forward stepwise multiple regression analyses revealed that body weight, navicular drop, and standing foot angle predicted mean peak heel forces during forward and backward walking.

CONCLUSIONS

Heel forces during forward and backward walking increase as body weight and navicular drop magnitude increase, and they decrease as standing foot angle increases. Subtle differences in foot, ankle, and knee joint postures and kinematics can affect heel forces even among normal subjects. Injury and protective bracing or taping may further affect these heel forces.