Y. Wu, M. Shaff, T. Heath, T. McKissick, T. Farnsworth, J. Higgins, J. Hebdon, J. Sirrine, D.E. Lankford FACSM

Brigham Young University-Idaho, Rexburg, ID.

Previous studies have demonstrated that backward walking may be implemented in training programs due to its lower impact on the joints of the lower extremity and benefit on cardiopulmonary system. However, little research has studied the impact of backward walking (BW) on ventilatory threshold (VT) and subsequent training responses. PURPOSE: To compare cardiovascular responses between forward and backwardwalking. METHODS: Participants (n=22, m=15, f=7) completed two graded treadmill walking tests to exhaustion in a repeated randomized crossover design. The first test was completed with the participants walking forward (FW), and the second test with the participants walking backward. Tests were performed at least 72 hours apart. Both tests were started at a self-selected speed at 3% grade, with grade increasing 1% every minute until an RER of 1.0 or greater was achieved for three consecutive readings, at which point speed increased 0.2 mph and grade 1% every 30s until exhaustion. Heart rate (HR), oxygen uptake, RPE, and expired gases were recorded throughout the tests. VT was determined using a combination of the V-slope method and identifying rise in VE/VO2 with no change in VE/VCO2. Paired t-tests were used to compare difference between tests. RESULTS: There were no difference in VT as a % VO2peak(FW=68.06%±6.1%, BW=69.91%±10.2%, p= 0.52). There were significant differences between tests for VT (FW=38.06±6.4 ml.kg.min, BW=28.6±5.5 ml.kg.min, p2peak (FW=188±8.5 bpm, BW=180±14.2 bpm, p = 0.003). CONCLUSION: Interestingly, these results suggest that mode of exercise alters oxygen uptake at VT, and HR at VT but not VT as %VO2peak. These findings may be applied to threshold training at a lower heart rate with BW resulting in less impact than forward walking.

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