Hansen, EA and Smith, G. Energy expenditure and comfort during Nordic walking with different pole lengths. J Strength Cond Res 23(4): 1187-1194, 2009-Energy expenditure and comfort for Nordic walking with self-selected and 7.5-cm shorter poles and ordinary walking were measured during uphill (12°), downhill (12°), and horizontally. Twelve (11 women and 1 man) Nordic walking practitioners participated (mean ± SEM: 171.5 ± 1.5 cm, 67.0 ± 2.7 kg, 50.6 ± 2.4 years, and maximal oxygen uptake of 43.4 ± 2.8 mL·kg−1·min−1). Energy expenditure was calculated from oxygen uptake and comfort was self-rated. Differences in physiological responses between the 3 locomotion types at each slope were first analyzed by a 1-way analysis of variance. In case of significance, Student's paired samples 2-tailed t-test was applied twice to test for differences between the 2 pole lengths and between Nordic walking (with self-selected pole length) and ordinary walking. The corresponding differences in comfort were evaluated by a Wilcoxon matched pairs test. The relative exercise intensity during Nordic walking with self-selected pole length ranged between ∼44 and 87% of the maximal oxygen uptake across the different slopes. For comparison, it ranged between ∼29 and 80% during ordinary walking. Uphill Nordic walking with short poles compared with poles of self-selected length caused 3% greater energy expenditure. Notwithstanding, comfort was similar. Horizontally and downhill energy expenditure and comfort were similar between pole lengths. Compared with ordinary walking, Nordic walking required as much as 67% greater energy expenditure. Comfort was similar for ordinary and Nordic walking for each slope. In conclusion, shorter poles caused greater energy expenditure during uphill Nordic walking, whereas comfort was similar to poles of self-selected length. The substantially enhanced energy expenditure of Nordic walking compared with previous studies reflects the vigorous technique used here.