Mechanics In Exercise: Torque

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Qualitative Torque Analysis

A simplified qualitative method can be used to determine relative torque forces. As an example we can compare the relative torque forces through the hip, knee, and ankle joints. First, take a photograph of barbell squat in a full descent with a perspective perpendicular to joints plane. Draw a line of force through resistance on its center of gravity, straight up and down, parallel to force of gravity. Gravity acting on both body mass and added mass (barbell) contribute to resistance. Incidentally, compression forces act upon joints during squat stance. On the barbell squat, center of gravity is over instep (between forefoot and heel). If it is not, individual will fall over, toward the center of gravity.

Now, draw three separate horizontal lines, perpendicular to line of force from each joint articulation (ankle, knee, and hip) to line force. If image is not exactly viewed from the side, "horizontal" lines can be drawn in perspective to picture as shown. Once diagram is complete, a relative comparison can be made on the torque forces of the hip, knee, and ankle.

Olympic-style Front Squat Qualitative Torque AnalysisBodybuilding-style Squat Qualitative Torque Analysis

  • Line of gravity positioned over instep
  • Feet push down into floor
    • creates a vertical reactive force moving body and weight upward
  • Examples
    • Olympic-style front squat (diagram 1 above)
      • Barbell positioned infront of body
      • Torso more upright
      • Relatively high knee torque (at bottom position)
    • Bodybuilding-style squat (diagram 2 above)
      • Barbell positioned high on shoulders
      • Torso moderately sloped
      • Torques more moderately distributed between knee and hip
    • Powerlifting-style squat
      • Barbell positioned low behind shoulders
      • Torso highly sloped
      • Relatively high hip torque
    • Box Squat
      • Participant sits back on box
      • Very low knee torque
  • Also see Squat Analysis

Other Compound Exercises

  • Torque forces equally distributed through multiple joints
    • Synergistic mechanics
    • Greatest gross force production through true compound mechanics
    • Exposes kinetics chain to particular forces necessary for adaptation
  • Torque forces shifted toward target joints
    • Emphasizes target muscle group or joint movement
    • Decrease torque forces through venerable joint
    • Too great a "torque shift"
    • Subtle torque shifts (if any) may be more beneficial than more drastic torque shifts
      • since greater weights can be used, thereby increasing overall strength performance.

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