RESULTS: Angular Kinematics

Segment angle.

The angle between the upper and lower arm during the standard push-up was greater than the corresponding angle during the diamond push-up. The maximum counter-clockwise angle when performing a standard push-up was -97 degrees. This was much larger than the maximum counter-clockwise angle for a diamond push-up, which was -53 degrees. The maximum clockwise angle for the standard push-up was -23 degrees. The maximum clockwise angle for the diamond push-up, measured at -1 degree, was much smaller than the standard push-up. The range of motion for a standard push-up was 74 degrees, which was significantly higher than the range of motion for a diamond push-up, which was 52 degrees.

Figure 3. Upper arm angle during the standard push-up (left) and the diamond push-up (right). The upper arm angle was calculated from the vertical axis about the elbow joint. Anatomical position corresponds to zero degrees. Increasing values represent clockwise rotation.

Joint angle 1.

The motion of the elbow joint was similar when performing both styles of push-ups. However, the maximum flexion and extension angles as well as the range of motion varied between the different styles. For the standard push-up, the maximum flexion angle was 288 degrees and the maximum extension angle was 188 degrees. The range of motion for the standard push-up was 100 degrees. As for the diamond push-up, the maximum flexion angle corresponded to 277 degrees and the maximum extension angle was 187 degrees, making the total range of motion 90 degrees. The standard style of push-up provided a greater range of motion for the elbow joint than the diamond style of push-up because there was a larger angular displacement between elbow flexion and elbow extension.

Figure 4. Elbow joint angle during the standard push-up (left) and the diamond push-up (right). The elbow joint angle was calculated as the angle between the upper arm and the forearm. Anatomical position corresponds to 180 degrees. Increasing values represent flexion.

Joint angle 2.

The shoulder angle motion was similar when performing both styles of push-ups, however, the maximum and minimum angles of the motion varied between the two styles as well as the range of motion. The maximum adduction angle was 247 degrees for the standard push-up, while the maximum adduction angle of the diamond push-up was smaller, corresponding to 225 degrees. Likewise, the maximum abduction angle when performing the diamond push-up was also smaller, calculated at 165 degrees compared with the 213 degrees for the standard push-up. These observed differences in angle measurement indicate that there was a much larger range of motion executed when performing the diamond push-up; the range of motion for the standard push-up was 34 degrees compared to the range of motion for the diamond push-up, which was 60 degrees. Therefore, the difference in the range of motion between the two styles was 26 degrees.

Figure 5. Shoulder joint angle during the standard push-up (left) and the diamond push-up (right). The shoulder joint angle was calculated as the angle between the upper arm and the clavicular segment. Anatomical position corresponds to 270 degrees. Increasing values represent abduction.

Joint velocity.

The angular velocity of the elbow joint was similar when executing both styles of push-ups. The maximum flexor velocity for the standard push-up was 187 deg/s, while the maximum flexor velocity was not much different for the diamond push-up, calculated at 155 deg/s. The maximum extensor velocity values were even closer in number; the standard push-up's speed was (-)187 deg/s and the diamond push-up extensor velocity was clocked at (-) 173 deg/s. The reason why the two styles of push-up have similar velocities was because the same subject executed both forms and was instructed to perform them at a relative constant speed so joint angle, not speed, could be analyzed.

Figure 6. Elbow joint angular velocity in the standard push-up (left) and the diamond push-up (right). Positive values represent flexor velocity.

Angle-Angle Plot.

The shoulder and elbow angle plots shown below were changing at a constant ratio. From this, we concluded that the shoulder and elbow joints were coupled. There was a greater degree of coupled shoulder and elbow movement in the standard push-up because the graph shows a steeper slope. In the standard push-up, the arms stay relatively close to the body throughout the movement, therefore decreasing shoulder abduction while increasing elbow flexion during downward movement. In the diamond push-up, the arms are positioned further from the body, which creates more shoulder abduction relative to the standard push-up. Elbow flexion increased as the movement progresses during the downward movement.

Figure 7. Coordination of elbow angle and shoulder angle in the standard push-up (left) and diamond push-up (right).