Graded forward and backward walking at a matched intensity on cardiorespiratory responses and postural control

While several studies compare backward walking (BW) and forward walking (FW) in terms of heart rate (HR) and rating of perceived exertion (RPE), workload (VO₂) was not matched to control for intensity levels (Hooper et al. [1]). Moreover, acute effects of inclined BW on postural control and ankle musculature has not been investigated. This study was designed to compare cardiovascular, metabolic and perceptual responses, changes in center of pressure (COP) motion, and muscle activation of tibialis anterior (TA) and gastrocnemius (GM) to control quiet stance posture immediately following inclined BW and FW at a matched intensity.

Seventeen healthy young adults completed three lab sessions 7-14 days apart. Session one, maximal oxygen consumption (VO_2max) was measured using open-circuit spirometry for each participant. Session two, participants performed BW for 15-min. Session three, participants performed FW for 15-min at matched intensity of BW. Surface electromyography (SEMG) measured the muscular activity of the TA and GM during bilateral stance on a force plate for 30 s prior to and immediately following BW and FW under both eyes open (EO), and eyes closed (EC) conditions.

HR, VCO₂, RER and RPE were significantly greater during BW compared to FW. Increased muscle activation and COP motion was elicited immediately following BW compared to FW under EO and EC.

Results of this study indicate BW requires greater cardiovascular, metabolic, perceptual and neuromuscular demands than FW, which may cause postural instability particularly to those with compromised balance. While there are benefits to BW in rehabilitation settings, these factors should be considered when prescribing BW for training and/or rehabilitation exercise program (Duffell et al. [2], Warnica et al. [3]).