His design pivoted around a bearing under the foot , in order to ensure that torque did not built up to dangerous levels .
French sporting goods manufacturer Jean Beyl made one of the first attempts to solve the twisting fall problem .
Jean Beyl 's design pivoted around a bearing under the foot , in order to ensure that torque did not built up to dangerous levels .
French sporting goods manufacturer Jean Beyl made one of the first attempts to solve the twisting fall problem .