Physiological responses that account for the increased power output in speed skating using klapskates

The present study investigates which physiological sources support the increase in mechanical power output ((W) over dot(out)) that can be obtained using klapskates in speed skating. It was hypothesized that the increase in W-out could be achieved through an increase in gross efficiency or an increase in aerobic power ((W) over dot(aer)). Six speed skaters performed a submaximal and maximal 1600-m skating test with both klapskates and conventional skates, to measure gross efficiency and maximal (W) over dot(aer) during speed skating. The rate of oxygen uptake ((V) over dot O-2) and post-exercise blood lactate concentrations ([La]) were measured and video recordings were made. (W) over dot(aer) was calculated from (V) over dot O-2. (W) over dot(out) was derived from the power needed to overcome air and ice friction. Gross efficiency was calculated as the ratio of (W) over dot(out) and (W) over dot(aer). In the maximal tests, the subjects skated faster with klapskates compared to conventional skates (10.0 vs 9.6 m . s(-1)). They sustained the resulting higher (W) over dot(out) with klapskates with an equal (V) over dot O-2. [La] was, however, 1.7 mmol . l(-1) higher when klapskates were used, which might reflect an increase in anaerobic power. During the submaximal tests the skaters generated equal (W) over dot(out) with both types of skate. Although not statistically significant, (V) over dot O-2 and (W) over dot(aer) were, on average, lower when klapskates were used compared to conventional skates [mean (SD) 0.3 (0.43) 1 . min(-1), 105 (143) W]. Despite the lack of a statistically significant difference in (W) over dot(aer), gross efficiency was shown to be significantly higher with klapskates compared to conventional skates (16.3% vs 14.8%, P = 0.02). We conclude that the increase in (W) over dot(out) when the subjects were using klapskates could be explained by an increase in gross efficiency rather than an increase in (W) over dot(aer).