Effects Of Cadence Changes During Uphill And Downhill Walking On Metabolic Responses In Women

PURPOSE: This study examined the effects of cadence changes during a leveled and slope walking on metabolic responses. METHODS: Ten healthy young women (23.7 ± 1.3 yrs, 160.8 ± 3.5 cm, 58.1 ± 8.9 kg) participated in a total of 25 randomly ordered testing sessions. In all sessions, they walked on a treadmill at a speed of 3.5 kph for 5 min. The condition of each session was one of the combinations of 5 slopes [20% downhill (20D), 10% downhill (10D), leveled (LV), 10% uphill (10 U), and 20% uphill (20 U)] by 5 cadences [preferred cadence (PC) and 80% (80PC), 90% (90PC), 110% (110PC), and 120% (120PC) of PC]. At first, their PC was determined at each of 5 slopes, then their target cadences were calculated. Except for PC conditions, their walking cadence during testing was maintained by a metronome. In all sessions, their heart rate (HR) and oxygen uptake (VO2) were measured. RESULTS: PC at 20D, 10D, LV, 10 U, and 20 U was 116.8 ± 7.1, 113.6 ± 6.5, 105.0 ± 3.7, 98.7 ± 4.4, and 98.4 ± 6.4 step/min, respectively. PC at LV was lower than 10D and 20D (p < 0.05). HR and VO2 in PC at 20D, 10D, LV, 10 U, and 20 U was 102.0 ± 2.8, 95.6 ± 2.0, 94.8 ± 2.2, 129.0 ± 2.5, and 165.9 ± 2.1 beat/min, and 13.0 ± 2.0, 11.0 ± 1.8, 14.6 ± 2.1, 26.3 ± 2.7, and 36.3 ± 2.9 ml/kg/min, respectively. HR and VO2 in PC at LV was lower than 10 U and 20 U (p < 0.001). Cadence changes from PC within each slope showed a increased HR (p < 0.05) except during 20D-90PC and 10D-90PC, and a increased VO2 during LV-80PC, LV-120PC, and 10D-120PC (p < 0.05). Compared to LV-PC, all other conditions elevated HR (p < 0.05) except 10D-PC. Compared to LV-PC, VO2 increased in all slopes of 10 U and 20 U conditions (p < 0.001), and decreased in all slopes of 10D and 20D (p < 0.05) except 20D-120PC. Compared to LV-PC, VO2 increased during LV-80PC and LV-120PC (p < 0.05), but not changed in LV-90PC and LV-110PC. CONCLUSIONS: Beyond 10% free uphill walking at 3.5 kph, HR and VO2 increased without changing the cadence from the leveled walking. During downhill walking at 3.5 kph, the preferred cadence reduced than the leveled, but HR and VO2 did not change. During uphill walking with or without changing cadence, in general, HR increased and VO2 decreased.