Muscle activity during backward and forward running with body weight support

Area of Science:

• Biomechanics
• Human Movement Science
• Exercise Physiology

Background:

• Understanding the biomechanical differences between forward (FR) and backward running (BR) is crucial for optimizing training and rehabilitation.
• Body weight support (BWS) is a tool used to alter loading conditions during locomotion, potentially influencing muscle activation and perceived exertion.

Purpose of the Study:

• To investigate the effects of varying levels of body weight support (BWS) on muscle activity, preferred speed (PS), preferred stride frequency (PSF), and rating of perceived exertion (RPE) during both backward running (BR) and forward running (FR).

Main Methods:

• Ten participants performed BR and FR on a treadmill with 0% to 80% BWS.
• Muscle activity of rectus femoris (RF), biceps femoris (BF), tibialis anterior (TA), and gastrocnemius (GA) was recorded.
• PS, PSF, and RPE were measured across different BWS conditions and running directions.

Main Results:

• Increasing BWS reduced muscle activity (BF, TA, GA) and RPE, regardless of running direction.
• Rectus femoris (RF) activity showed an interaction between direction and BWS, being higher during BR than FR.
• While overall muscle activity (BF, TA, GA) and RPE were not direction-dependent at a given BWS, PS and PSF differed between BR and FR, with BR exhibiting lower PS and higher PSF.

Conclusions:

• BWS significantly influences muscle activity, PS, PSF, and RPE in both BR and FR.
• Running direction may not alter muscle activity magnitude or RPE for a specific BWS level, but it does affect the muscle activity pattern, PS, and PSF.