Water depth effects on impact loading, kinematic and physiological variables during water treadmill running

Area of Science:

• Biomechanics
• Exercise Physiology
• Sports Science

Background:

• Water-based treadmill running offers a low-impact alternative for exercise.
• Understanding the effects of immersion depth on running biomechanics is crucial for optimizing training and rehabilitation.

Purpose of the Study:

• To compare impact loading, kinematic, and physiological responses during treadmill running at different water immersion depths.
• Investigate the effects of mid-shin, mid-thigh, and xiphoid process immersion levels on running parameters.

Main Methods:

• Eight participants ran on a water treadmill for 3 minutes at each of three immersion depths.
• Tri-axial accelerometers measured running dynamics and impact loading rates.
• Heart rate data were collected to assess physiological demand.

Main Results:

• Running at mid-shin and mid-thigh immersion depths resulted in significantly higher peak impact accelerations and impact loading rates compared to xiphoid process immersion.
• Stride frequency increased, while stride length decreased with lower immersion depths.
• Physiological effort, indicated by heart rate, was significantly lower when running immersed to the xiphoid process.

Conclusions:

• Water immersion running above the waistline (xiphoid process depth) alters gait kinematics.
• Higher immersion depths significantly reduce impact loading variables during running.
• Running immersed to the xiphoid process decreases physiological demand compared to lower immersion depths.